Hello from Canada: I am actually a retored electronic technician, and also hold an intewrp[rovincial electrician's ticket. However, most of my electrical experience was in industry where the environment is quite different. I had long heard of the U.K. rule of thumb that you never plugged more than one item into a socket. I had also heard it said that the distribution did not have the rulke that each reduction in wire size had to be aditionally protected by an appropriately sized breaker or fuse. This latter more or less corresponds to what you described with your description of the ring circuit. so that one item rule makes a lot of saferty sense in the U.K. In other european countries, I believe the usual circuit is 7 A. at 220 V. 60 Hz, and is typically supplied as one phase of a 3 phase Wye, meaning that the neutral is at one electrical end of the 220 to 240 volt line. Large items such as dryers,m stoves etc. would logically have to have spoecial circuits to accommodate their needs. In Canada and the uU.S,., within the scope of residential power, not including apartment complexes etc. the typical sascenario is as follows: From the transformer in the street which may be mounted on a utility pole, there are two secondaries, each for 120 volts 60 Hz. these are then wired in additive series, resulting in 240 volts, and could be sized to render as much current as a KA. Then the point where the two secondaries are joined, otherwise known as the center tap, is attached to a wire headed to the ground (earth). At ground level a hole of about 6" depth is dug and a 6 or more foot rod is driv3en fully into the ground at the bottom of that hole leasving only a few inches inside the hole. the wore from the senter tasp is then thermit welded onto the rod, using a disposable ceramic or steatite cup that holds the powder used to make the thermit flash. Once the flire from the flash has subsiced, the lot is buried. this then is the neutrasl connection, except that the neutral concept has more to do with the neutral wire that goes from that connection at the top , with the two hot wires to the building entrance. there it is formed ina droop, also known as a water loop. which encourages rain and other water to drop down it and away from where those wires are to enter the conduiit gooing down to the entrance. In some cases that conduit may enter the building there and pass through the consumption meter inside, but in mre recent installations the tendency ois to have the meter outside so it can be e=more easily read by passing hydro trucks. still newer is to have a radio transmitter associated with the meter so it can be remotely read without any need to bother the resident. The type of drop cable sued from the pole to the building is often of the type klnown as NSF cable. It has 2 insulated conductors for the live wores and a bare one for the neutral. In the city this may be replaced by underground installations, but ultimately they all end up oin the backplane of the fuse or breaker panel. In some cases there is a separate master breaker/disconnect swithch before supplying the backplane of the panel, in other cases the master breaker is part of the breaker panel and the incoming entrance is connected to that 2 pole master breaker, and thence feeds the backplane to them feed the individual circuiit breakers. (In iolder installations the panel may be designed to use fuses, but gradually this is being phased out.) The typical (and minumum size) circuit is 15 Amperes. this is used for most circuits, with notable exceptions being stoves, clothes dryers, electric water heaters and heat pumps, all of which will be fed by special circuits either direct wired or using special connectors, each being described precisely in the tabbles at the back of the Electrical code book. Each of these has a unique design so that it is physically impossible to insert a wrong male cap (plug) into a given receptacle of a different size or capacity. there are many different approved designs for differnent needs, some of which are intended for 120-240 volt use, and others for three phase use (industrial and commercial only) upto (Canada) 347/600 volt three phase. this differs in the U.S. where the usual commercial voltage is 460 volts delta. While some industrial equipment goes even higher than this, I will stop here as above that it becomes an electrical specialty, due to the added dangers and equipment needed to work on that type of installation. Hence, back to the domestic domain, the 240 volt usage is notably differtent from 220 to 240 volt systems commonly used in pother countries. Not only is the frequency different, but the neutral is not in the same configuration, so ot would be very unsafe to try and harness North american 240 volts to power European 220 to 240 volt equipment directly - with one common exception. Many small electronuic devices use switchmode "electronic transformers" usually sealed in small balck boxes, to convert the incoming pewer to low voltage, class II (inferring 24 volts or less) to supply the small devices. these electronic power blocks (technically known as switching power supplies) use complex electroniuc power conversion techniques to convert just abpout anything to just about anything else. simply READ THE LABELS. Since these are usually designed with the whole world in mind, they are apt to be rated to use anything grom 100 to 240 volts at frequencies ranging from 48 to 62 Hz. so to accommodate from Japanese power (100-200 volts 50 or 60 hx. depending on locale) too240 volt 50 Hz. U.K. amd australia, and possibly New Zealand. they may either have the plu=gs molded intot eh black box or, for the larger sized they use one of a number of international business machine recessed makes in the black box, coupled with a cord set compatible fore the market in wheuch they are to be shipped. Hence, only yesterday, when my new neighbout came to me with a small laptop which he ahd brought from New Delhi India which had "problems" the foirst questuion I had was how long has this computer been sitting dead without having power connected to keep up the lfoat charge on its battery? when I made him think for a bit the answer came otu to be close to two weeks. so immediately I had him bring it out. when I looked at the power block onthat one, Iwas able to go to my parts cupboard and grab a North American power cord to fit the power block, swapped it for the one he had from India, plug it all in and let it recharge as we dealt with other matters. (I also told him not to let go of the cord from India as he could never know if or when he might again need it.) The"electronic transformer" or switchmode supply in the black box would rectify whatever poer it got, then sense the resulting D.C. voltage and adjust the duty cyxckle with which it switched that power at high frequencey into the step down transformer for subsequent re-rectification and flltering. At the same time, the circuitry would sense the outgoing voltage and use that through another high frequency feedback channel to auto-compensate the duty cycle of the powering circuit to result ina regulated output voltage for the use of the computer. the laptop would then further regulate that power according to changes in the activity of the computerm, and added safety device circuits built into the battery caretridge to insure against danger of the battery spontaneuosly catching fire. that dsaid there is an added caution: Never try to fix orreplace a laptop battery with a substitute. that battery cartridge is actually more than just a battery and must communicate with the laptop ongoing to ensure safe operation and prevent dangerous fires. On my own business Laptop, when I plug it into power there is aset of lights that flashes a sequence as that communication operates, so immediately I know it has powered up the charge circuit and stabilized itself for further use. this is obviously more than a mere battery.
R. E. Bruce Martin in europe (at least here in the netherlands) the standard is 16 amps. We get ~ 230 volts but the breaker is 250 volts I believe. So that’s quite a lot of power on one circuit. Most of the times it’s enough for consumer electronics, so a washer or dryer has the same type of circuit as any other one, just one for it’s own.
Not if the cooker has a 13amp plug on it you can just plug it in. And you can get three phase cookers and also three phase supplys in domestic situations. Cheers
Not really it all depends on your cooker what current it's drawing. But yes the only thing on that circuit unless of course you have a cooker supply unit with a socket outlet on it then you need to allow for diversity. take the first 10A then 30% of the remainder plus 5 A if you have a socket on the circuit. I would have a double pole cooker switch with no 13amp socket on it. Cheers
Single ovens can be powered by a 13a plug. Often these would be wired on a separate circuit so you don't trip the fuse by using the oven, kettle, toaster, microwave and dishwasher at the same time. I have never seen 3 phase domestically in the UK, except if someone has a workshop. You would need a different meter and feed into the house. I understand the US does as you need it to have any decent power output from 110v.
The 12 Amp rating is pretty simple. In a nutshell, for a continuous load, the circuit has to be able to carry 125% of that load. And 12/15 = 0.80 = 80%. So a 15 amp circuit can carry 15 amps for a short period of time, but shouldn't carry more than 12 amps continuously.
Not sure if this has been covered before. But the ring final circuit was invented to allow a 3KW heater to be moved room to room. 3KW or 3,000 watts at 240 volts is 12.5 amps. The ring final circuit allowed for electric heating which was going to be the number one heating source in the 40's as gas was old hat. As it happened electric heating turned out to be not that great but other electrical wonders did require an outlet for electricity. Therefore fuses came into being to protect items that didn't need 3KW to operate. The inventors of the ring final circuit never imagined televisions, computers, usb chargers or any of the other modern electrical items that we love so much. The ring final circuit is a throw back to simpler times.
Jason, I'll chime in on the 12-amp thing. It's part of our electrical code, and related to the trip curve of the circuit breakers we use. As you likely know, an electric motor in a stall condition pulls approximately four metric craptons of current, and they are essentially stalled when you first turn them on. This is to say, an electric motor pulls a ton of current trying to start. If a 15-amp breaker tripped immediately at 16 amps, it would be impossible to start most electric motors. There are delays designed into the breakers (and fuse wires where used) to accommodate this. In practice, a fifteen-amp breaker will take several hours to trip when loaded at, say, seventeen amps. That's okay though, because the wiring it's protected would also take a similarly-long time to actually become hot. Our circuits are not designed to be fully loaded to 100% constantly, and in fact a breaker loaded this way will eventually trip. We define "continuous" loads as those devices that are likely to be operated for three hours or more at a time. These loads, in order to not trip the breakers they are attached to, are limited to 80% of the circuit rating. 80% of 20A is 16A, and 80% of 15A is... guess it... 12A. Hair dryers, operated only for a few minutes at a time, are often rated to the full fifteen amps. I don't know about vacuum cleaners. I've definitely seen some higher than 12 amps, and, really, if it takes three hours to vacuum your floor, you just need a smaller house. Devices like electric space heaters with 15-amp plugs will most certainly be limited to 12 amps, legally.
A minor point - most UK houses don't have a 3-phase supply so, while many modern cookers can be configured for a 3-phase supply if one is available (there are link options in the terminal box of the cooker for this) they are usually supplied pre-configured for single phase operation. It's interesting how the system is evolving - new installations now using RCBOs that give individual earth leakage as well as overload protection for each circuit off the consumer unit and consumer units now have to be metal (too many fires in plastic consumer unit apparently)
Hi Jason - I wonder if you are old enough to remember the early versions of the 13A plug that did not have the insulated skirts on the L and N pins? (I still keep coming across them on some of my ancient electrical stuff). I think I only made the mistake of wrapping my fingers under a plug far enough to get a zap once but that was enough. I'm glad earth leakage trips are becoming commonplace. As a follower of the OSTAR races I was moved by the tragic death of Lizzie McMullen during preparations for the '76 race - something that an RCD, a common enough item even back then and costing only £5 today, would have prevented.
I remember them, and was electrocuted by one as a 3 or 4 year old when I pulled the plug out the wall and put my little fingers in ... People like me (or the less lucky ones who didn't survive it ...) are the reason we have that insulation on the pins. Apparently I was unharmed ;) I obviously have some aptitude with things electrical since my next trick at the age of 6 or so was teaching my mother how to wire a fuse when one of the fuses blew because "I saw how Dad did it". Described how you screw it out, wrap the wire round, screw it in ... Later, when we got a new cooker and I was about 12 or 13, I wired that in. Delivery guy said they couldn't wire it in, so I just started at it, went and pulled the fuse and began unwiring the old one. Delivery guy says, wide-eyed "Are you really going to let him do that?" and my mum said "Well, he seems to know what he's doing". Explained to the guy how it's just a plug except bigger, and pointed out where the live, neutral and earth go ... My dad checked it later and said it was fine. Of course, when I bought a new cooker a few years ago, it said I needed a qualified electrician to install it. I did it :P Guess what? I work in IT :D
Very interesting video, however I don't think you have hit on the real reason why the fuse is needed in the plug. I scrolled through the comments and maybe I missed it if someone else has made the same comment, if so sorry! But the reason I believe there is a fuse in the UK plugs is not to prevent the entire ring from going down. The reason is that, as you stated, the wire for the small appliances is rated at only say 3-5 amps, so an overload to say 10 or even 20 amps would not cause the 32A breaker to trip and the small wire would burn up and cause a fire. To protect the wire, the appliance, and everyone around there has to be a fuse. Basically, the breaker is for 32Amps, the wires to the sockets can presumably carry 2x26 amps (both sides of the ring), so the 32A protection is fine for the ring, but will not protect the appliance, you need the fuse at each plug. You are correct that it is the ring that creates this need for the fuse and nowhere else in the world do they use rings and thus don't need fuses in plugs, but the reason is not quite as you stated. Definitely would be interested if someone has a different perspective.
It's clear that the answer to the question in the title is that having a fuse in the plug allows different gauges of flex between the plug and the appliance to be used and always have a fuse which will blow before the flex overheats and causes a fire. This has nothing to do with the use of ring or radial circuits. The question that hasn't been answered is why isn't it also necessary on other systems which have 15A to 20A radial circuits? What's to stop anyone in the US or Germany plugging in a lamp with a 3A rated flex which will catch fire and burn down the house if a fault in the lamp draws 10A? Theoretically the answer to that last question is that the appliance should contain a fuse matched to its cord but when did you last see a table lamp or a radio with its own internal fuse?
In Australia we use the radial system also but our usual household power outlets are rated at 10 amp the wiring in the walls is rated at 15 amp and the circuit breaker/fuse is typically rated at 8 amp. The reason for these ratings are simply that is an item plugged in to the wall shorts out the first thing that SHOULD drop is the breaker/fuse however before circuit breakers some people were lazy and would use heavier fuse wire to repair blown fuses to stop it blowing if it was just the overall load on the radial being greater than the fuse rating. so then as a secondary safety point the wall sockets were only rated at 10 amp so they would over heat and hopefully stop working before they caught fire. The wiring in the walls was the highest rating simply because that is the last place you want fire inside the walls themselves and because on a radial system it needs to carry all the current for the entire leg not just to a few sockets. The down side to this is that when houses are being built cheaply often they will try to use as few circuit breakers as possible so you have one for lights one for power until they reach a possible radial draw of well in excess of 8 amp before they will put in a second breaker. In many cases you will end up with a house with 2 power breakers one that may have all wall sockets but for one or two rooms on it and the last room or two on the second breaker and if the draw on the first breaker reaches the limit it will drop out but the one room or two wont drop power at all. This would be easily solved by balancing the likely power draw over both breakers (say by putting the laundry and kitchen on different breakers and maybe then only putting half the sockets in each room on one breaker and rest on the second), but this is considered wasted time as they only put in second breaker if they have to. Interesting video though as I had known you had fused plugs and used ring system but didnt know what the difference was and thought the fuse was simply a first point of failure point for ease of repair.
I didn't see an answer to your question in the comments, so here it is. NEC (national electric code) specifies that a circuit should not pull more than 80% of its rated load continuously. Which means the max continuous load on a 15 amp breaker is 12.5 amps. I am not an electrician so I don't claim anything I say is right. So a google search for "NEC 80% rule" is a good starting point to do your own research. I believe NEC 210.19 is the correct article.
I once attended a callout out to a farm that had a 3 phase supply. The neutral broke on the powerpole of a delta wired system which resulted in 415 flowing down the live of the phase that the house had been wired to. The fuses didn't protecting the circuits from that and every piece of electrical equiptment in the house and every wire in the wall was destroyed. Thankfully thankfully the 100A incoming network fuse blew protecting the house from burning down !
Now that we live in rural France we can only dream of a 100A supply. The standard these days is 30 to 60A with more available and the inevitable three phase which can be foisted on you if for example you have a ground source heat pump or need too much amperage for the local transformer to cope with (think very rural). We only use radial circuits but the number of outlets per circuits and RCD's required make for a pretty good solution. I personally can't stand ring mains and think they should be phased out. However I do miss the British socket with a switch to isolate prior to unplugging... I just don't like the French earth pin sticking out of the socket...
The US National Electrical Code limits devices with a plug to 80% of the circuit's rated amperage. If a device needs to draw 15 amps on a 15-amp circuit, it needs to be hardwired. At a guess, this is because the plug introduces extra resistance to the circuit.
Eric Lloyd I'm not an electrician, but am familiar with electricity through my decades of hobbies involving electronics. My guess is that the 80% standard is there to account for the fact that people don't like using appliances in the dark. 12A for appliances and 3A for the lights. (This is really going to sound stupid) If an electrical circuit is in the form of a ring, would not the whole circuit open if any of the sockets were to have no plug in them, and would not the appliance with the highest resistance receive the greatest share of that 230V line voltage?
Installing an electrical supply is an involved and technical task which is why for roughly 10 years now you have had to be qualified by law, even to work on your own house. There are distinct advantages to a ring main, one of which is that every outlet is connected to the Consumer Unit via 2 cables, and therefore 2 earths! This part of the regulation has recently been upgraded so that each earth cable now has it's own terminal behind the outlet, making it safer still. Some houses were wired with radial circuits but this is discouraged even if it's not banned, I don't know if or when that might have happened.
The 12A appliance limitation may be part of *derating*. This is where the amp rating of a wire is reduced because of how many conductors are in a conduit, or because the wire passed through an area of very high temperature (attic). The theory of derating is that if there's some external factor which might stress the wiring in such a way as to reduce its ability to conduct its rated current safely, we reduce its current rating by a fixed percentage (and thereby reduce the load it can handle). Only problem with the UK system is that if the whole house is on a "ring" circuit (with spurs), the segments of wire closest to the consumer unit will conduct a great deal more current than those in the middle of the ring. It should also be noted that, because the UK voltage is roughly 230V, where the U.S. voltage is roughly 115V, the amperage draw for devices of comparable construction should be half of the US appliance rating. That is, a toaster in the US rated at 10 amps in the US should run at 5 amps in the UK. (Relates to the power equation: power = voltage times amperage.) I used to be an electrician here in the States.
great vid that finally explains what a ring circuit is, i live in us and have been watching a ton of uk electrician videos its interesting how differently things are done i have to say the consumer units you guys have over there are way nicer than what we have
What you tend to get nowadays with RCDs and overcurrent breakers you tend to drop the entire circuit if there is a fault regardless. Unless there's a serious overcurrent situation, a 32A breaker tends to trip somewhat quicker than a 13A fuse blows and if there's ANY earth leakage at all, the RCD (which may precede the entire system, or just a set of breakers) trips and turns off anything it's connected to. It's fairly common to have one RCD for a set of 3 to 5 breakers (for example all socket circuits).
I’m not an electrician, but did study mains power fundamentals at college as a part of an electronics course. An overview of how power is distributed and how voltage is stepped down to safe levels. There are rather a lot of omissions in this video and some inaccuracies. I do know someone who is very highly qualified on the subject and would be more than happy to comprehensively let you know where you’ve gone wrong! I won’t tell him as it’ll be tortuous though! 😂
Nice description as I have always wondered about the fused plugs in the UK. I live in NZ and we use the star configuration, known as Multi Earth Neutral. No fuses on our plugs. (Our plugs are the same as Australia.) Houses are usually single phase 230/240V @ 50Hz and standard plugs/sockets are rated at 10A. High current appliances, like electric stoves, are wired using thicker cable (15Amp) direct to the appliance from the houses fuse box. (There can be a high current plug and socket used to make the appliance easily removeable.)
Can a 3 amp appliance draw 15 or 16 amps on a *radial* circuit without tripping the breaker? If the circuit breaker fails (even on a radial circuit), the fuse in the plug is still better than nothing.
It's not entirely accurate that a fuse is required just because of the ring circuit. The purpose of the fuse is to protect the flexible cable from the plug to the appliance. In the case of a low-power device, like a table lamp, the flexible wire might only be rated at 3 or 5amps, and if it's damaged or the insulation is degraded it might carry sufficient current to overheat the cable under a fault condition yet not enough to trip the circuit breaker. That is an issue for outlets rated at anything significantly above the flexible wire rating - so it also applies to outlets on circuits rated at 10A, 15A or even higher in some areas. Radial circuits in the UK aren't even limited to the 16A that is commonly seen. A 32A radial circuit to a kitchen is very common (and sometime 40A), and what's also common is for their to be a standard outlet on such a circuit. There is also nothing in the UK regulations that stops multiple sockets on a 32A radial. Indeed, many electricians prefer those to rings as they are simpler to test (and they make particular sense for a dedicated socket circuit for kitchens). The simple fact is that it makes a lot of sense to have fuses in plugs with ratings suited to the flexible cabling, whatever the regime,
Just need to point out most houses are single phase in the UK. Also strange to see so many people get worked up by the fact that the UK does things differently from the rest of Europe. It's legal to use radial circuits for sockets but electricians prefer ring circuits because they are superior and safer in several ways. If we introduced regulations that forced us to use radial circuits we would be forcing ourselves to adopt a lower standard. Regulations are there to provide a minimum standard not to lower them. I imagine that other countries regard the the extra safety features as not worthwhile for the extra effort. Especially as components and appliances are of higher standards theses days. But honestly most electricians in the UK are very comfortable with ring circuits and don't regard them as complicated or troublesome. As for the fuse in the plug. We could eliminate it but why would we want to go the effort to remove a safety feature? We already have lots of regulations and if we start introducing regulations that force us to adopt lower standards it defeats the purpose of having regulations. Live and let live, don't get upset that people in different countries do things differently.
+David Lee 'It's legal to use radial circuits for sockets but electricians prefer ring circuits because they are superior and safer in several ways.'...why are ring circuits safer?
Mark William Mandigers It is safer in a number of ways. Multiple routes to Earth is one for instance. It can also be more cost effective requiring less copper per house. The UK plug has numerous safety features, something the plugs in some countries lack, as long as we buy decent quality plugs and not cheapo ones on fleabay that do not meet our strict standards. Do some research and you can easily see the strengths and weaknesses of the UK system, and you will soon also see the inherent problems in some of the other systems around the world. On the education front, tell that to a child who has been electrocuted by some of the really iffy systems out in the world. Just go to a hotel in Egypt that have an open element heated shower and you will see unsafe.
I think the reason for limiting power to 12 amp for each device is because if what you have plugged in draws 15 amps on a 15 amp breaker then there is a greater chance of it tripping. Plus that breaker may still have to be able to provide power to lighter loads like a lamp for example.
VioletDragon Projects Modern all electric dual oven/hob units typically require more than 32A and require larger cross section cable and a 45A MCB. Such cookers should NOT be connected to a 32A feed!
+Jason Coulls @ 2:00, those are transmission voltages, and in the UK they extend from 400 kv to 33 kv. The primary distribution network there extends from 33kv to 11kv, and secondary distribution begins at 415v. But I don't know why you got involved with that to explain why UK plug-tops are fused. The reason plug-tops are fused is the same reason any circuit or subcircuit is fused, to protect the circuit downstream of that fuse...irrespective of whether a ring or radial circuit is feeding into the fuse. Both ring and radials in the UK use a minimum of 2.5 mm sq cable, which is rated up to 27 amps...therefore if you're reducing the cable size to say 1.5mm sq (rated to 16 amps) when you plug an extension cord into the circuit, you need to protect that cord by introducing a fuse into its plug-top. That's the simple answer. Your explanation is overcomplicated, and quite frankly you're a good example of a little knowledge being a dangerous thing.
I enjoyed watching your video I like how the uk is wired vs the us it seems the uk 🇬🇧 is wired the way that if you overload a circuit only the one outlet will trip before anything else. I appreciate it 😎😎👍 I’m from the USA 🇺🇸 and have overloaded circuits before and the entire room loses power. Good information ℹ️
Still none the wiser. That malfunctioning US lamp could still draw many times its rating without tripping the breaker. A fused plug would seem a sensible idea whatever the system, enabling a direct match with the rating of the appliance.
15A is the maximum current, but regulations say you shouldn't run it continuously at that current. I suspect that's why you see 12A on many appliances. For instance, 15A X 120V = 1800W. However, most appliances are rated between 1400-1500W because that power level is considered safe for continuous use.
We have both single and three phase available to residential consumers here in Greece. For single family homes they tend to push one for three phase power but that mainly benefits the electric company which charges more for 3 phase service. Most kitchen ranges can be wired for 3phase to help balance the load better instead of piling up heavy draw appliances on a single phase. Another issue being enforced now in Greece is the testing of the wiring and breakers in residential units every 14 years and commercial and retail locations every year. The latter not enforced if electric service has not changed due to new renters or new businesses. That is bound to change as the government finds new ways of draining the pockets of the people here.
I suspect the 12.0 amp limit on consumer items is simply because the manufacturer doesn't want to have to add a very strong notice saying this device must have an individual circuit breaker, consumers want to plug their vacuums into any Outlet that's convenient to them so one with an extra 3 amps wiggle room is perfect
most sensible electricians tend NOT to use ring mains, as radial circuits are much easier to test, and fault find and if the circuit fails at one point after that point the circuit will be dead .Not so in a ring main.. so in a kitchen instead of a ring main. 2 or 3 25 amp radial circuits should be installed giving a system capacity of 50- 75 amps in the kitchen , and also if ,due to a fault you lose one circuit you still have power in that area. A ring main is the ONLY circuit that still works when it is faulty.and are easily overloaded if damaged.... and you wont know....
In the US, you can only draw 80% of the rated breaker current continuously. Therefore, 12 amps is 80% of 15 amps. One can pull 15 amps for some duration before the breaker heats up and will trip. At 80% continuous amp draw, the circuit is good indefinitely.
In the USA most homes have 4 to a maximum of 6 outlets (120V 15A) per room. Kitchens have dedicated circuits for the refrigerator (120V 20A) and stove (240V 30A). The breaker panel "consumer unit" in a typical home is rated 100A feeding the home with 15, 20 and 30 amp breakers with the majority being 15A breakers. if for any reason there is a short in say that lamp, the breaker trips shutting down a maximum of 6 devices. There is logic to shut down the area as to not cause damage to another device like a TV or computer located in or near said outlet. Also this idea is easier to add or change circuits without disrupting the rest of the home something not possible in a ring circuit. Now on to answer you question about appliances under to 15A rating . My vacuum cleaner is rated at 8A and a tea kettle rated at 12A. Manufactures are creating more efficient appliances so that we can use more at the same time. For instance in the kitchen, I can use a tea kettle toaster and microwave all at the same time because the circuit is rated at 20A while other parts of the home (bedroom, living room, dining room......) are at a 15A circuit. My entertainment center is dedicated to one 20A circuit. As far as fuse in a plug, yes we have them available as well as plug strips with breaker and fuse protection built in. Along with GFCI (Ground Fault Circuit Interrupter) and child safe outlets have been in the USA for more than 25 years. Maybe now you can get an understanding why we do it this way.
The idea of the ring circuit is that the load is equal across the whole circuit but much more difficult to add or rework. On our system the load equalization is done in the main panel by distributing breaker amperage evenly or as close to equal on the two main legs. The neutral is constant across the entire home as is the earth but that is fed directly to the earth. My home was built early 1930's and used our relic "knob and tube wiring" (look it up) method with only feed and neutral wires and no earth. Many homes still exist that used this wiring but I upgraded my home many years ago.
By the way your videos are a helpful explanation as well as entertaining. I'm also an IT guy but on the infrastructure side and electric is also part of my job.
The ring circuit is a wartime relic, but it’s pretty easy to add to it - you can just take a spur off a socket on the ring. Each ring main, which requires surprisingly little copper, and is run like a radial but with a return, can supply about 7.5kW. That’s pretty good.
Oh I know Knob & Tube.... Each time I've bought a new house or moved, it's been top of my list to look for. Even the house I'm in now has a few dead circuits from when it was first built that was the next thing after the knob & tube...
12 amp devices because the wire's actually technically good for 25 amps and a 15amp breaker won't pop when the device pulls a surge at start-up since the system is ground/common based at 115/125/105/130v... it makes it a universal standard for use across much of north america. You can actually wire 20 amp circuits using special outlets and such legally (or just put a 20A on the breaker panel) but for the most part the outlets themselves are the limiting factor since 12Ax125v=1500w and THAT is the standard used. Gets a little weird and there's tons of variances but if you're dumb enough to buy a power supply or device in the US that uses more than 1500w it's either going to be 240v or require the special outlet. There used to be quite a few standards including a 20a three blade rotating plug for kitchen appliances like oil fryers and I remember a 2ph 240v my dad showed me which had five blades and had to be bolted into the outlet AFTER it was turned 18° but I never found out what it was used for - probably shop equipment or something. But the standard here is 12A continuous draw and 15a peak load and the breakers toss at about 17a@125v unless they're made by Federal Pacific Electric in which case they fuse on and you die.
I recall in the early 70s we had Round three pin plugs/sockets and the plugs were rated at 15amp and did not have fuses, UK. I believe they are still in use today.
No, the round pin plugs would have been only in old houses in the 1970s. The square pin fused plugs came in in 1947, but it took many years before all old houses were updated.
An excellent video. But here in the UK it is very rare to have a three phase supply within a domestic property. Household cookers do not need that sort of connection. In my house a large and a small oven run to a (correction) 20 amp breaker on single phase.
That bit about three phase residential power struck me as strange. I'm betting he's using the term to mean something other than three separate sine waves each leading the other by 120 degrees. Three-phase power is only used in commercial and industrial installations here in the USA, and it would strike me as odd for the UK to be different; there's just not much need for big three phase motors in the home. Maybe he's using it to mean a power supply from a center-tapped transformer. In the USA most homes get three-wire power feeds, two hots and one neutral (a center tap bonded to earth). The voltage between the two hot lines is 240; the voltage between either hot and neutral is 120. The 240 volt circuits are used for high-current appliances like clothes dryers and kitchen ranges. The two hot lines are effectively two phase power, 180 degrees phase difference. Do some UK homes get something analogous with both 220 and 440 volts available for circuits?
Yeah Domestic properties in the UK usually only have single phase 230V supply, although the cables in the street have all three phases, so it is likely your next-door neighbour will be on a different phase to you, which, I am told, is why you shouldn't share extension cables over a garden fence. I believe in the US you have two 120V phases domestically, so you can have 240V for larger appliances?
That is correct. The lower voltage used in North America is yet another historical relic. A voltage around 220-240 is actually pretty close to optimal for a mains voltage with current technology. It's a good compromise between safety (lower voltages are safer), the need for insulation (lower voltage = less need to worry about insulation and arcing = lower costs), and metal costs for wires (higher voltage = lower current for a given power = less money spent on copper). With electrical technology circa 1885, however, a voltage around 110 was optimal, because electricity then was used almost exclusively for lighting, and with the technology at the time, it was cheapest to manufacture carbon-filament incandescent bulbs at wattages commonly needed for interior illumination at that voltage. That cost advantage for incandescent bulb manufacture hasn't existed in over a century (and incandescent bulbs themselves are now mostly historical relics), but North America is thoroughly locked into 120 volts. The three-wire electrical feeds became common in the post-WWII years as a way to allow houses to have high-current appliances without using expensive super-thick wires or requiring an extremely disruptive doubling of the standard mains voltage.
We did have a uk house that had 3 phase, we had to get it installed because my partner is Italian and wanted a huge cooking hob. Admittedly it could be wired to run on single phase but in that instance it would reduce the number of rings that could be used together automatically. 3 phase meant there was less delay for the pasta, a top quality investment :-). It also proved to be awesome when we sold the house as the guy who bought it in only came to look at it because 3 phase was listed in the property details and he wanted to run a kick ass milling machine in the garage.
I suspect the answer to the 12A question is that the wire from the plug to the applience is probably something like 18gauge wire which has a lower ampacity (rating).
18 gauge is not used in any wiring in the USA. The minimum gauge is solid copper 14awg wire that can carry 20 amps safely but our laws limit to only carry 15 amps.
Harry Lanza if that is 120v then that would explain your need for more amps we have just 240 more volts less amps we can run 3kw off any standard plug in the house were as having 120 for some products and 240 for others seams silly to me
It's 1.5mm cable which is rated at 18amps it's overated on purpose there is a British standard maximum sized cable to be used in a British plus top is 1.5mm BS1363...
I can see some advantages to the UK system; your radio blows a fuse but your lamp stays on. However, most North American appliances have their fuses internal to the unit itself instead of in the plug, so effectively we have the same thing, just a little further along the line. Advantage to the UK fused plug method, you MUST unplug it in order to change the fuse; it offers that layer of safety. While most NA appliances have their fuses in special access sockets, it is still possible to encounter current if the unit has not been unplugged. As for the vacuum cleaners etc. that are hyped as 12 amps even though the circuits are 15, this is more a selling point as to the power and torque (the sucking power, if you will) of the unit's motor. And you wouldn't want unit too close to the circuit limit of 15 amps since the couple extra amps drawn at startup would blow the circuit every time and you'd never get your work done! Not to mention the small fortune in fuses. Of course circuit breakers save money. LOL. So 12A is the logical upper limit for vacuum cleaner motors.
most manufacturers 'embellish' the marketing speak of their products power by quoting the peak load that the appliance draws... this is often an instantaneous load at start up (especially for electrical motors). So its not the continuous draw load. You can see this quite easily if you look at the advertising for the Wattage (or Horse power) quoted for a product and then work back from 230v (uk) or (110v (USA) to calculate the current draw, and you'll find its simply not possible. In soe areas such as power tools and machinery this has become a Top Trumps type marketing war which is plainly nonsense but shifts units off shelves when the consumer has a mind set of "bigger is better"
Don, Most appliances here also have an internal fuse. However ring circuits go back to 1948. At that time, appliances were not the low power electronic devices we have now. Lamps were an exception (although to be fair incandescent lamps have a fuse - the bulb). The idea of a 3kW electric fire being able to draw 9 kW through its appliance flex due to a fault is rather frightening as it wouldn't be able to take 3 times overload. Also bear in mind that originally consumer units used fuses (and indeed many houses in the UK still have rewireable fuses to this day). Fuses can take a fairly large overload before they blow, so a 30A fuse probably won't blow at 35A. Having a 13A fuse, that definitely would blow at 20A therefore solves this issue. A 32A breaker also probably won't blow immediately at 35A, as it would take a while for the bi-metallic strip to heat (although a 0A to 35A surge would almost certainly trip the breaker immediately as the other form of overcurrent protection - the solenoid would activate). In its own way, we could go back to radial circuits now and use lower amp breakers, however we would still be using BS1363 plugs and socket outlets. Because of that they would all be fused. Not only that, but even if the regs changed tomorrow, there are installations that will be running with rings for decades. The design of BS1363 only has the one flaw. They bloody hurt when you step on them in the dark.
I remember my relatively small studio unit in England had something like 7 circuits? Though literally everything was electric. So we had a circuit for the oven, and one for hot water, both of which were something like 40 amps. Then there were at least two lighting and 3 power circuits. And then a master breaker off something like 70 amps. I do in fact believe that there was evidence the unit had two-phase power running into it as well. (given there was a commercial property downstairs and 4 residential units in the two upper floors, I suspect maybe the commercial unit had access to full 3 phase power, even though the shop in it probably wouldn't need that, while the residential units were all using different sets of 2 out of 3 phases. Who really knows, honestly. XD) Point is there were a lot of power points, and a lot of circuit breakers for what was actually quite a small space. By comparison the larger one bedroom ground floor unit I have now in Australia seems to have just 3 circuits in total, though in this case the oven, hot water and a heater are all gas, rather than electric like in the UK unit...
the reason for the limit is because of surge amps. allow me to explain, in a North American house we generally use 15 amp breakers but often times in a condition of particularly high load an appliance rated for 15 amps will throw the circuit for no other reason than it has exceeded the maximum capacity of the breaker and home wiring so by rating devices at 12 amps even under excessive load the breaker will not be tripped unnecessarily. Also unfortunately our appliances do not run on true three phase because each line is not out of phase in frequency in true 3 phase there are 3 distinct pulses of electricity 120 degrees out of phase of each other from separate generator windings. Our 240 volt appliances run on 2 separate 120 volt breakers coming from the same central breaker and mains line wired in series to double voltage.
In Australia we run on uk power but our power system is based on the usa otherwise we would have uk wall sockets . looking at my fuse box this is what i found - 2 power circuits = 1 rcd on each power circuit rated at 10 amp - lighting circuit = 1 rcd at rated at 8 amp . when it comes to business i believe all thats done is the 10amp power power circuit are rcds/breakers are changed to 15amp.
The 12A issue: most consumer grade vacuums in Canada use SJ / SJW type wire of the 2 conductor 17ga or 2 conductor 18ga variety. Based on Underwriters Labs current-carrying ratings, the 17ga hits roughly around the 12A limit for runs of 0 to 50 feet. The 18ga technically shouldn't be used at all, since it tops out at about 10A max capacity and if you're unlucky enough to have a vacuum that draws more than that, you WILL find the cord getting quite warm during constant service (yes, even with a 12A vacuum). Anything over 5-10 minutes runtime should be viewed with caution. (This is also why your detachable black PC 110/120v cords all have that 10A max rating stamped on them, they're 18ga albeit a much shorter run, and are actually correctly labeled for their application.) With respect to vacuums, however, I've seen firsthand the danger this poses, as in the past I've witnessed 12-foot and 20-foot 2/18 cords ignite when they had 12A running through them. Don't believe the sticker if those piddly little things claim to be able to handle 13A or 15A. Oh yeah, and DON'T let prongs get dirty or corroded, you'll have an even bigger fire hazard on your hands. :P
There’s a slight confusion here - a UK consumer unit is usually rated to 100A, while the ring circuit MCB/breaker is 32A. A fuse can also break the circuit in the event of an earth fault, but this is not its primary function. An RCD and/or MCB is much quicker.
Thanks. There's a number of points where my wording was a bit wrong. I realized after uploading, that the fiery lamp wire comment mentioned that the lamp was on a 3amp fuse, when I meant to say low rated wire, then say the problem can be avoided by putting in the fuse. Doh!
You need a serious earth fault to trip a fuse or MCB, which mostly never occur unless you have a short to earth. Also a fast blow fuse can be as fast as 10ms, I don't think a MCB can be much faster.
Nice tutorial,. I'm in Canada. It's a safety margin. Dont want the breaker tripping all the time. For example a vacuum. When the vacuum is started there is a power spike. At 12 amps the breaker can tolerate it because it's quick. If the vacuum pulled 15 the margin is not there and would pop the breaker.
Just for fun, that immediate high current drain on motor loads is called "locked rotor amps" (LRA). On large equipment where this is important, there is a panel which specifies the running and LRA, along with voltage and such. It is called locked rotor amps because if you started such a motor but locked it down so the rotor couldn't turn, this is the load you'd get. But, free to spin, a motor only draws that for a short duration on start-up.
So I guess to restate: circuits in the UK are commonly 240v*32a=7.68kw max at the breaker, which if something shorts is easily enough to start a fire without tripping the breaker, made practical in terms of wire gauge by connecting the run at both ends (and reduced transmission loss from lower current for the same wattage because of the voltage). While non-appliance circuits in the US are 120v*15A=1800kw max at the breaker and so having less less ability to start a fire if there's a short, and reduced ability to arc because of the lower voltage.
If something shorts then the breaker will trip in a fraction of a second before there is any danger of the wire overheating.this is because a short will allow a much larger current to flow, exceeding the 32A the breaker is designed to allow through
Maybe you should also talk about the distribution voltages within the building? USA = 110V UK = 240V, Australia = 240V with yet another type of plug and socket?
Some homes in the UK have radial circuits. For some reason my flat has a ring final circuit, but both sockets in my bedroom have their own 16 amp breaker because they are on their own radial circuits, for some reason.
depends on the need and ease of wiring at the time, if your flat was converted from a house at some point, or has been rewired in the last 10 years or so, its likely that the landlord/agency didnt want the hassle of setting up a full ring-main for 2 plugs, for example, its just easier to set up a radial for each room and really has no effect on the operation of appliances
I live in a block of flats that was built around the very late 1960's/early 70's. The hallway socket, the two in the lounge and the one's in the kitchen appear to be on a ring, but the two in the bedroom both have their very own breaker.
I'm not sure about some of the stuff you said e.g. 32A consumer units - there's several 32A circuits in a CU, along with other amperage circuits for lights etc & 3 phase to cookers (which I wish was the case as I could run my tools on it!). I *think* (IT engineer here also ;) that the main reason for the fuse is for when you get a short that DOESN'T draw the full 32A. In this case the circuit breaker (RCB) in the CU won't trip but the fuse in the plug WILL blow. With 15A circuits, this difference between operating amperage and consumer unit breaker amperage is much less, so there's less need for a fuse (although it will always help, having an extra layer of safety). I think this is what you were getting at whilst worrying more about your drawing skills, yes? :) Keep up the good work expanding the empire over there and send back some maple syrup for HM the Queen. :)
A little knowledge is a dangerous thing. UK and Ireland are almost identical regulations. Consumer units are normally minimum 63 amp to 100 amp depending on size of house. Cookers are not supplied with 3 phase 400volt as standard. Cookers. Immersion units and showers are supplied on a separate Single phase dedicated ring normally with 32 amp mcb as protection. The fuses in plugs are to prevent fire in appliance by short circuit on ring main, although mcb and even older elcb will most likely trip first.
You kept saying the consumer unit is rated at 32 amps. The circuit breaker protecting the ring final circuit is rated at 32A not the consumer unit. there may be several 32A circuits (say an upstairs, a downstairs and a kitchen ring, then several 6A lighting circuits, maybe another 6A circuit for smoke alarms and intruder alarm, A cooker circuit which may be 40A, a shower circuit, etc etc. the 32A ring you mention is just one of many in the consumer unit (sometimes referred to as the fusebox)
a fused plus is safer, and easier to fix.... but in the UK how does one household run on a 32Amp service when you have an all electric kitchen? in the US our ranges can pull up to 50 Amps at 240Volts.... and the clothes dryers about 25 amps.... you combine those with the rest of the house and you'd be blowing your main fuse in the UK.... how do the newer homes in the UK handle this? here in the US, our "CU" is rated at 200 amps...
He got a bit muddled as a normal socket rings on the CU will be rated 32A, but the CU will be higher depending on the size of the house. Someone else in the comments said 100A is the most common for regular sized houses now days, but I honestly have no idea. Most ovens don't have plugs. You wire them into a junction box that is on its own ring (possibly along with a seperate hob, and a single socket) conected to an easily accesible, bright red switch nearby, that sits in for the socket switch we would normally have. Small houses / appartments may have a plug in oven, but then the kitchen will have its own ring. There wont be space for more than one other large aplience in the kitchen, but in my wifes old flat she could blow the main fuse by running the oven, the washing machine, the kettle, the microwave and the hoover, all at the same time.
Sometimes, the wiring itself can go wrong, so you need to cut electricity to an entire spur. I had an electrical outlet short out and melt without having anything plugged into it.
The 12/15A question in the US is due to breakers only being rated for 80% continous load. Not like in Europe where fuses are rated for 100% continous load. 15A x 0.8 = 12A. You have the same issue with charging EVs. You have to have a 50A breaker to set up 40A charging, since 50 x 0.8 = 40. Rather odd for a European. :-)
Nice one Jason. I did NOT know that my heater/electric hob and oven (I use all gas, but still) ... were on a three-phase circuit. In fact, I'm fairly certain they're not. Is it not the case that the CU is fed with three-phase? Then two 32A phases get split to power the two separate ring mains (for upstairs and downstairs) ... and the third phase goes to the kitchen to give the big appliances their own 32A circuit? This would appear to make more sense, as I have no 5-pin triple-phase connections anywhere in my home, nor have I ever seen any in domestic situations. While I'm at it (and I know you're not an electrician, but still, it's nice to ponder) I'm sure you'd agree that Live and Neutral are both Hot, yes? And the Earth is NOT a return line ... so L&N (being AC) must serve as each others return, each serving half of the cycle? ... and, if that's the case they're necessarily 180 degrees out of phase. So, surely that's a kind of 2-phase system ... and surely both phases would need to be 115-120v, so that out-of-phase they provide 230v-240v peak-to-peak ? So, are we on a US system, just terminated differently ? >scratches head< Furthermore, can the US system provide 220v with alternative termination? I hear that machine shops over there use 220-240v ... so that would be a neat way to provide it - and would make us a lot closer, electrically, with our cousins over the pond. Especially since I just learned that many building sites in the UK use 110v tools and equipment, to minimise risk of death in those situations where electricity is used outdoors and in high risk environments... I never knew that : ) ... but it would make sense if our domestic supply was really a split phase 115v acting against each other to provide 230v Ain't mains electricity f'ing confusing : )))) Best left to the experts, always : ) Don't feel you need to struggle for an answer, I'm just unloading my curiosity.
North American outlets are regulated by the NEMA standard which calls for a 20% safety margin. So a 15A receptacle should never have an appliance plugged in that draws more than 12A.
The ring circuit is old and outdated. Yes, it had it's place in history but in the present it is just easier for electricians to just run one wire through the house as opposed to running one wire to each room. With the advent of RCD breakers it's a safe enough system. I have lived in the UK for 20 years total and I've rarely known anyone to blow a fuse in their plugs but many people losing the entire ring because the RCD breaker has popped.
I dislike the video because you did not say the CB will trip in case of the lamp fault in the ring circuit. Instead you said that the wire will be on fire, what the CB does if it let the short circuit happen and does not trip?
in US they limit a lot electronics to 12 or 13 amps just to protect the old outdated house wiring that is in aluminum instead of copper. plus we have 99% of outlets in pair outputs so people tend to plug multiple things in same outlet location, on top of that the outlet might have a neighbor outlet on same breaker/wire so there might be something there too. in new construction in 95% of the time I put 20 am barkers with 12 gauge wire and not more than 2 outlet locations in same wire/breaker, but knowing how American people dont know electricity, I like to put 1 outlet location per breaker
Ivan Kishov Jeezuz!! One MCB per outlet!!?? I would have needed an industrial consumer unit/ fuse box for the kitchen alone in a house I used to own ... 27 outlets ... Just in the kitchen. THAT'S why a ring main with fused plugs is so much better. ONE breaker covered ALL those sockets ... Last lived there 28 years ago ... The house is still standing
It depends. USA consumers dont want fuses, more then that, in some areas of USA if you come to a house that have fuse system, you must not touch it or overhaul it to new standart.
15 amp circuits huh. That's a lot less power at 110 volts than it is at 230 I'd have to draw 3 kilowatts to overload a 15 amp circuit, but at half the voltage that's only 1.5 kilowatts. I think the worst part of 110 volt systems is that you very quickly run into needing a 240 volt or higher circuit anyway for various appliances... Then again in Europe I was being electrocuted repeatedly by the metal casing of my friend's computer. Why? Because while the computer should technically have been earthed, many household wiring circuits, especially in older properties have no ground wire. Similarly, the socket design is such that there's usually not much stopping you putting an earthed plug into a socket with no earth. (you can tell the socket doesn't have ground/earth because the pins for it are missing.) That really was pretty dubious, I have to say...
I don't know about that "very quickly." We simply don't have a need for many appliances over 1500W. Our "cookers" (stoves/ovens), electric dryers, electric water heaters, and permanent electric space heating does usually require 240V, and whole-house air conditioning systems. For everything you'd normally plug/unplug and come in frequent direct contact with, 120V and its associated 1800W (1500W continuous) limit is quite sufficient.
Nice try in explaining but not completely accurate. There is no 3 phases to domestic property in the UK. It is all single phase and neutral so your electric cooker is also single phase 240vac and protected by a 40A breaker and usually a 100A or 63A ELCB (Earth Leakage Circuit Breaker) or properly referred to as an RCD (Residual Current Device) or RCCB (Residual Current Circuit Breaker) which services the ring main circuuts as well as cooker and electric showers and boilers. The ring main ensures that there is very little voltage drop when you plug in a heavy load like a kettle or toaster as well as distributing the load more evenly. The 2.5mm sq wires they use is rated at 26A but is more than capable of carrying 32A even for long periods but might get slightly warm. Some larger houses that are built nowadays will use 4.0mm sq which is rated at 32A. All appliances come with a cable or flexible cord that is rated at 13A. This is the current limit of the plug and appliances that can be plugged in. The appliance however will have smaller current carrying capacities and so are best protected from short circuit with a fuse that is rated for the size of conductkrs in the appliance. This will prevent the appliance from overheating and catching on fire rather than the flexible cable. Domestic fuse sizes are rated at 1A, 3A, 5A, 10A and 13A si it is important to fit the correct size fuse for maximum protection.
I'm really sorry, but this. Idea simply confuses what is quite a simple subject. Electricity can be distributed by rings or spurs, whichever is the most convenient. The entire point is that each home has a maximum amount of electricity available, and you need to get it to where it is needed. In UK homes we have spurs to fixed heavy loads -cookers, permanent heaters, washing machines, and then we provide rings where lower power devices can be connected randomly where it's convenient. The ring is an efficient way of providing up to 32 Amps of current. One for the ground floor maybe, one for upstairs? Before we used rings, where each plug is protected, we used a system very similar to the US system where each socket outlet went back to the fuse box, and of course we had one fuse per circuit. Rings are convenient, and electricity distribution companies use them to connect their substations. They're simply an efficient way of doing it. Forget the daft numbers. 13a mains has proven to be safe and fits in well with our building system. It's not better or worse, just different. As for all this stuff about cable sizes, it's all down to what's called diversity. A 13A double outlet has two routes back to the consumer unit and shares the load. Fuses in plugs prevent more than 13A being drawn, which is the socket rating, only 32A is available from the breaker in the consumer unit. All these features allow trip free living. If your system trips under everyday use, you need an extra ring. It's so simple there is no need for confusion. We also need to not talk about multiple phases. Only a very, very few homes have 3 phase power, so adding that confuses, and the reason is safety. Three phase goes past your house, but each home just picks up one of them for 240V supply. 415V from our 3 Phase is simply unnecessary, and we don't do it. Older homes had a maximum load at the fuse box of only 45A, then it went up to 60A,a and now 100A is common at the consumer unit BUT few homes will every attempt to come close to using this amount of electricity because there's no need and we couldn't afford it! In my humble view, the is no need to make rings mains as complicated as this. They are exactly the same as the ring we use to supply our hot water to radiators all over the house. We don't return each radiator to the boiler, unless we use microbore, when it becomes like the radial systems US and Europe prefer.
Minor clarification here. In the US, *each* plug doesn't run all the way back to the panel ("consumer unit"). Each plug is on a "branch circuit", and there are a certain number of receptacles allowed per circuit based on the wiring (size) in use and the size of the circuit breaker at the panel. Typical branch circuits are rated at 15 amps (#14 wire) or 20 amps (#12 wire). For heavier load devices (like cooking stoves and air conditioners), larger wiring and breakers are used, but all breakers are housed in the panel. There is a main breaker in the panel, usually rated at 100 or 200 amps. Houses are almost exclusively single phase 115-125 volts. Commercial installations usually are served with 3 phase power and panels ranging from 200 amps and up (though anything above 200 amp typically involves a "cabinet" rather than a "panel"). I like the UK idea of putting fuses in plugs. It would increase the safety of electrical installations, and prevent whole circuits being blown when a single device is overloaded. But alas, if it's not in the National Electrical Code (NEC), it will not happen. (See my earlier comments on a different thread about the NEC.)
Cookers 3 phase? That's a new one on me. As far as I'm aware, only a single phase is delivered to the CU from the street transformer. The next phase goes to the next house, and so on. So how can a cooker be 3 phase?
Tim Long well it's true that people are using the word phase in the wrong way, a cooker, or I think you mean stove or oven, could easily be three phase. The elements are just a resistor and I don't think I can explain what phases look like when joined together if you don't know what LOL. 60 or 50 cycle, when the first phase is in between directions and at neutral, the second phase is just starting in the opposite direction so you have twice the power, in three phase they are 90 degrees out of phase so you never reach a neutral electrical charge and the net result is greatly increased! If you never seen a waveform and you can't picture in your head, don't worry about it.
Lots of kit gets plugged into 13A outlets with the adaptors that come with shavers (which are usually fused internally at 2A) or with the Chinese 'deathdapters' - which allow US flat two pin and EU round 2 pin plugs to be connected. They're truly dodgy devices and should really be banned - but they're a fact of life. An appliance fault would indeed have access to 32A of current - but the weak link on lower current demand small items is the cable - and the usual result is the cheap ones fail at some point where the conductor is weak, and they burn out - sometimes spectacularly - but luckily often this happens with no outwards sign - as lots of imported equipment has very underrated conductors - with hardly any copper - kind of like having a 3 foot long fuse!
Never thought about it like that, done it for almost 20 years, especially the slim Euro plugs worked well (well, I used UK plugs more, of course). check it out: www.digitpress.com/room-of-doom/cm/displayimage.php?pid=4151&fullsize=1
Uhhhh... The voltage ranges for distribution here don't really make a lot of sense. Low-voltage distribution that you might expect at your house for instance(right before the transformer that gives you your 120/240V power in the U.S.), can range from about 2.77kV to 14.4kV (open wye voltages, for delta configuration that range would be 4.8kV to 24.9kV) Then there's high voltage distribution at around 23kV, 46kV, and 138kV (open wye configuration here), and then you have transmission where you would see the high voltages over 200kV as you mentioned. Some of these ranges may be specific to companies in my area, but generally speaking those are the ranges you will see.
Thank you! I'm still amazed that having been making and practicing vlog videos for a year, things are suddenly blowing up now. I did my "100th vlog" just in November, and only had 32 subscribers! This is insane how fast things are going suddenly!
I just watched your recent vlog explaining that, I'm an IT tech but always had an interest in how apps are made on various devices. Hope the boom continues!
Jason, Some of the junk splooged out from communist China to the U.S. have these damn dumb fuses. Yesterday I bought a new fan, and yes it has a plug fuse and no supply of extra fuses.I'm cheap and run alot of old fans and other 40 to 60 yr. old appliances which have no plug fuse. What is your opinion if I snipped off the plug with a fuse and put on conventional plug without a fuse? Asking for your opinion as one nonelectrician to another.
correction(from an educaited electrician in Denmark): its not Kvolt, its just Volt, else in your exampel you'll have 270 000Volt, wich is not the case, cant say much about the U.S other than they have 120V between a fase an Neutral. The U.K(and almost all of EU) how ever has 230-245V between a fase and neutral, and 400V between a fase and a different fase. U.K is also 50Hz, U.S is 60Hz
Jason Coulls link dosn't work. But look jason, if it was that high voltage then you would be fryed just by standing 5m away. I think you're mixing something together that you've read about the grid power, connecting cities together. I work as an electrician every day. Not knowing what you talk about is one thing, but being stubborn when some one is friendly and tryes to correct you, is a completely diffrent thing and in this field, informing ppl wrong about this is really bad, because they might then end up with a bad accident.
1) just remove the right paren that RUclips made part of the link. 2) Its the transmission voltage. You understand that right? You're talking about the socket in the house?
Jason Coulls yes im talking about the voltage going into your fuse box in your house and there for also the sockets, wich is what you where showing and talking about in this video, it makes no sense to talk about the transmission voltage, when your point is to explain why U.K plugs are the way they are, if you think the transmission voltage matters when talking about the house instalation, then i would politely advice you to stick to your softwhere programming.
OK. This is the last I'm saying on the matter. In the same way people might talk about the sun before talking about the earth, I talked about the transmission before talking about the residential situation.
Jason, thanks for the interesting plugs/electricity supply videos. You said that UK cookers are supplied with a radial 3-phase circuit - this is (generally) not true, almost all UK domestic supplies are single phase, unless you have a very big house! You are correct that electric cookers (and electric showers) are connected on a separate radial circuit as these are rated for much higher current.
Water heaters is another one often with their own radial circuit at least when the electricity is actually supplying the heating element as opposed to just supplying pumps and similar as in gas boilers.
His information is just out of date. That was the standard back when the retangular pin plugs came in, and remained the most common setup till when the number of houses with single phase cookers out numbered 3phase, probably at some point in the 80's. EEven then it was probably quite comon till the Home improvment boom of thee 90's when a lot of older houses were rewired and/or had their fuseboxes replaced with circuit breakers
You can't draw 15 amps through a breaker or a fuse rated at 15 amps. Also there is a current surge when power is applied to equipment. Fuses are always rated higher than what the equipment uses or they would keep blowing.
Actually, you can draw MORE than 15A, for a short time, until the breaker gets hot enough to trip. This feature is actually exploited by things like refrigerators, which have high starting surge currents. Going over the rated current for a brief time is not a fire hazard because the wires don't have enough time to get hot.
John D II actually a good bit of time an hour or more for a 15 amp. It'll hold a lot longer than a few minutes, that's why continuous (3hr or more) load is 80% of rated capacity. There's all different types of fuses with tons of different blow curves.
Hi Jason, I've noticed that the US (and probably Canada) quote 110v domestic supply with a 220v option and they go on to claim a 440v three-phase system. How can this be? OK, it's easy to double voltage from 110 to 220 but that doesn't explain the spurious claim of 440v three-phase. Is someone seriously missing out on RMS (Root Mean Squared)maths? In the UK, running 240v mains, this would equate to 480 volts three-phase, which is complete nonsense and we both know that this is seriously wrong. The phases are set out at 120 degrees to each other and the voltage between phases works out as: RMS V = the square root of 240 (squared) x 240 (squared) + 240 (squared), so: RMS V = 240 x cube root of 3 RMS V = 240 x 1.7321 RMS V = 415 V RMS (between phases), and 415 V is specified in the UK as 415 V. By the same token, the RMS three-phase voltage in the USA and Canada must only be 381 V. Quod Erat Demonstrandum.
I can't speak to RMS versus measured. Typically, residential power is supplied as single-phase 115-120V/230-240V. Inside the "panel", there are two live busses, and the voltage to ground for each is 120V. Measured bus to bus, the voltage is more or less 240V. This is considered (and referred to as "single phase"). The two power busses are 180 degrees out of phase with each other, and each rated at 120V. Thus, the bus to bus voltage is 240V. There are home devices (like cooking stoves) which take advantage of the 240V supply, but most consumer devices (TV, computer, lamp) use 120V. For commercial installations (with potentially larger equipment needs), the panels have three live busses instead of two. In this case, the voltages are more complicated depending on how they are generated (delta or wye). I won't go into commercial voltages, except to say that 120V is supplied to commercial installations along with the higher voltages through the same distribution system. (I used to be an electrician in Los Angeles some years ago.)
In America we call it a fuse box or circuit breaker box and I think the circuit you describe is called series for the UK and America uses parallel circuits. At least you have a drawing like a series circuit and that doesn't make any sense because voltage is not constant in a series. From the way you have a drawn I can't figure out what it means LOL. I have a degree in electronics and the comment that you have pinned doesn't make a whole lot of sense at all, much less the fact that the person can't spell. I guess I'm going to have to Google it and see what the heck you're doing over in the UK LOL. Okay, I finally found a circuit diagram on Google a ring is definitely the wrong word for it! The word implies a series circuit and that's not what it is. I don't know why they draw it going back into the fuse box? Electrically speaking, it's not a ring at all! It is however, the most contrary and bass ackwards thing I've ever seen. One thing to note for the so-called electricians here LOL give me a break. ( at least the ones I've read so far, I'm sure there are some real ones here) Watts divided by volts equals amps so at 240 volts you're only going to draw half the amperage for a 120 watt light bulb as you would in the US. This allows you to use a thinner wire in the UK. What you call radial or ring are both circuits that are series parallel. It's just that in the UK it seems to be one big series parallel and in the US we have different circuits for each part of the house and major appliances. something goes wrong in one room and only the outlets and lights for that room are going to blow a breaker. In the UK it blows the whole darn house LOL
It's not really more complicated. It's just that in America, we might have two circuits for the living room Outlets and one circuit for the dining room. It looks like in the UK they put the whole Darn House on one circuit LOL! They shouldn't draw it going back into the circuit breaker box like a ring because he electrically, it's the same thing; At least from the diagrams that I found on Google.
WIFIGHOST CRUISER Sorry but you're wrong. It IS a full ring. If you need to check it out properly you should search for UK consumer unit images and research the ring main more thoroughly. Inside the consumer unit EACH 32A ring main circuit has 6 wires: 2 brown (line), 2 blue (neutral), 2 bare copper earth wires that SHOULD be covered with green/yellow sleeving. Each neutral and earth wire is connected to the respective earth and neutral blocks and the PAIR of line wires are connected to the 32A breaker outlet. For any individual socket there are TWO parallel cable paths which means that the ring CABLE capacity is 52A @ 230v (typically, and definitely in ALL the houses I have seen is actually 250v) that's a total power capacity of 12.5 kW PER ring. We usually have at least two rings (upstairs and downstairs) and depending on the size and/layout of the house may have one or even several more. Power diversity comes into play also. Some of that can be effected by manual config at the consumer unit (fuse box) by for example, having a separate ring main for the kitchen/utility room. But that enables us to have a 3kW electric kettle, a four slice toaster, a microwave, a dishwasher, a fridge, a tumble drier, and a washing machine all connected to the ring main quite safely and without issue using a universal power plug (providing not all are switched on at the same time). If the ACTUAL working conditions are likely to exceed the 32A max load then a separate radial circuit or circuits can be provided or more likely these days, an extra ring main can be installed. The main reason a ring main is more efficient is that for the sake of a few EXTRA feet of cable over a radial 16A or 20A circuit (i.e. JUST returning the end of the radial back to the consumer unit, we can have as many sockets as we like on a ring main (under a certain square footage) and can plug in ANY moveable domestic electric appliance into ANY socket at ANY time. We can move that electric kettle anywhere in the house. Once a ring main has been PROPERLY and ACCURATELY installed and tested, the likelihood of a break in the ring occurring without some form of deliberate interference is miniscule. Current UK regs require that the installing is safety checked after ANY new installation work and checking a ring main for continuity (as compared to a multi socket radial) is simplicity itself and can be done from the consumer unit alone. Any faults are obvious albeit the location of the fault is slightly longer than a radial. Once a suspect fault is located and fixed however, it is MUCH quicker to verify correct operation than with a radial ... You just check at the consumer unit. Extending a ring main in essence is also extremely simple using single socket spurs (not the best way but legal) single or multiple fused spurs (i.e using a fused wall plate to protect the cabling from excess load) or by breaking into the ring and connecting a new socket with additional cabling. One other thing, unlike the US and Canada, the UK does not use (to my knowledge) aluminium cored wire in domestic environments and certainly not under 16mm^2 that I have ever come across in 45 years as a graduate electrical and electronic engineer.
Hello from Canada:
I am actually a retored electronic technician, and also hold an intewrp[rovincial electrician's ticket.
However, most of my electrical experience was in industry where the environment is quite different.
I had long heard of the U.K. rule of thumb that you never plugged more than one item into a socket. I had also heard it said that the distribution did not have the rulke that each reduction in wire size had to be aditionally protected by an appropriately sized breaker or fuse.
This latter more or less corresponds to what you described with your description of the ring circuit. so that one item rule makes a lot of saferty sense in the U.K.
In other european countries, I believe the usual circuit is 7 A. at 220 V. 60 Hz, and is typically supplied as one phase of a 3 phase Wye, meaning that the neutral is at one electrical end of the 220 to 240 volt line.
Large items such as dryers,m stoves etc. would logically have to have spoecial circuits to accommodate their needs.
In Canada and the uU.S,., within the scope of residential power, not including apartment complexes etc. the typical sascenario is as follows:
From the transformer in the street which may be mounted on a utility pole, there are two secondaries, each for 120 volts 60 Hz. these are then wired in additive series, resulting in 240 volts, and could be sized to render as much current as a KA.
Then the point where the two secondaries are joined, otherwise known as the center tap, is attached to a wire headed to the ground (earth). At ground level a hole of about 6" depth is dug and a 6 or more foot rod is driv3en fully into the ground at the bottom of that hole leasving only a few inches inside the hole. the wore from the senter tasp is then thermit welded onto the rod, using a disposable ceramic or steatite cup that holds the powder used to make the thermit flash. Once the flire from the flash has subsiced, the lot is buried. this then is the neutrasl connection, except that the neutral concept has more to do with the neutral wire that goes from that connection at the top , with the two hot wires to the building entrance.
there it is formed ina droop, also known as a water loop. which encourages rain and other water to drop down it and away from where those wires are to enter the conduiit gooing down to the entrance. In some cases that conduit may enter the building there and pass through the consumption meter inside, but in mre recent installations the tendency ois to have the meter outside so it can be e=more easily read by passing hydro trucks. still newer is to have a radio transmitter associated with the meter so it can be remotely read without any need to bother the resident.
The type of drop cable sued from the pole to the building is often of the type klnown as NSF cable. It has 2 insulated conductors for the live wores and a bare one for the neutral.
In the city this may be replaced by underground installations, but ultimately they all end up oin the backplane of the fuse or breaker panel. In some cases there is a separate master breaker/disconnect swithch before supplying the backplane of the panel, in other cases the master breaker is part of the breaker panel and the incoming entrance is connected to that 2 pole master breaker, and thence feeds the backplane to them feed the individual circuiit breakers. (In iolder installations the panel may be designed to use fuses, but gradually this is being phased out.)
The typical (and minumum size) circuit is 15 Amperes. this is used for most circuits, with notable exceptions being stoves, clothes dryers, electric water heaters and heat pumps, all of which will be fed by special circuits either direct wired or using special connectors, each being described precisely in the tabbles at the back of the Electrical code book. Each of these has a unique design so that it is physically impossible to insert a wrong male cap (plug) into a given receptacle of a different size or capacity. there are many different approved designs for differnent needs, some of which are intended for 120-240 volt use, and others for three phase use (industrial and commercial only) upto (Canada) 347/600 volt three phase. this differs in the U.S. where the usual commercial voltage is 460 volts delta.
While some industrial equipment goes even higher than this, I will stop here as above that it becomes an electrical specialty, due to the added dangers and equipment needed to work on that type of installation.
Hence, back to the domestic domain, the 240 volt usage is notably differtent from 220 to 240 volt systems commonly used in pother countries. Not only is the frequency different, but the neutral is not in the same configuration, so ot would be very unsafe to try and harness North american 240 volts to power European 220 to 240 volt equipment directly - with one common exception.
Many small electronuic devices use switchmode "electronic transformers" usually sealed in small balck boxes, to convert the incoming pewer to low voltage, class II (inferring 24 volts or less) to supply the small devices.
these electronic power blocks (technically known as switching power supplies) use complex electroniuc power conversion techniques to convert just abpout anything to just about anything else. simply READ THE LABELS. Since these are usually designed with the whole world in mind, they are apt to be rated to use anything grom 100 to 240 volts at frequencies ranging from 48 to 62 Hz. so to accommodate from Japanese power (100-200 volts 50 or 60 hx. depending on locale) too240 volt 50 Hz. U.K. amd australia, and possibly New Zealand.
they may either have the plu=gs molded intot eh black box or, for the larger sized they use one of a number of international business machine recessed makes in the black box, coupled with a cord set compatible fore the market in wheuch they are to be shipped.
Hence, only yesterday, when my new neighbout came to me with a small laptop which he ahd brought from New Delhi India which had "problems" the foirst questuion I had was how long has this computer been sitting dead without having power connected to keep up the lfoat charge on its battery? when I made him think for a bit the answer came otu to be close to two weeks. so immediately I had him bring it out. when I looked at the power block onthat one, Iwas able to go to my parts cupboard and grab a North American power cord to fit the power block, swapped it for the one he had from India, plug it all in and let it recharge as we dealt with other matters. (I also told him not to let go of the cord from India as he could never know if or when he might again need it.)
The"electronic transformer" or switchmode supply in the black box would rectify whatever poer it got, then sense the resulting D.C. voltage and adjust the duty cyxckle with which it switched that power at high frequencey into the step down transformer for subsequent re-rectification and flltering. At the same time, the circuitry would sense the outgoing voltage and use that through another high frequency feedback channel to auto-compensate the duty cycle of the powering circuit to result ina regulated output voltage for the use of the computer.
the laptop would then further regulate that power according to changes in the activity of the computerm, and added safety device circuits built into the battery caretridge to insure against danger of the battery spontaneuosly catching fire.
that dsaid there is an added caution: Never try to fix orreplace a laptop battery with a substitute. that battery cartridge is actually more than just a battery and must communicate with the laptop ongoing to ensure safe operation and prevent dangerous fires.
On my own business Laptop, when I plug it into power there is aset of lights that flashes a sequence as that communication operates, so immediately I know it has powered up the charge circuit and stabilized itself for further use. this is obviously more than a mere battery.
Wow. Thanks for the comprehensive reply. I'm going to pin this as the top comment on this video.
Were you heavily under the influence of drugs or alcohol when you typed this?
R. E. Bruce Martin I
It's all to do with the transformer wiring pattern and the waveform of the AC supply.
R. E. Bruce Martin in europe (at least here in the netherlands) the standard is 16 amps. We get ~ 230 volts but the breaker is 250 volts I believe. So that’s quite a lot of power on one circuit. Most of the times it’s enough for consumer electronics, so a washer or dryer has the same type of circuit as any other one, just one for it’s own.
Cookers and showers below 8kW are on a 32amp breaker and a 40amp breaker above 8kW and are single phase in the UK.
Not if the cooker has a 13amp plug on it you can just plug it in. And you can get three phase cookers and also three phase supplys in domestic situations. Cheers
Yes, most are on a single phase 32 Amp or 40Amp circuit though, however it should be noted that will be the only thing on that breaker.
Not really it all depends on your cooker what current it's drawing. But yes the only thing on that circuit unless of course you have a cooker supply unit with a socket outlet on it then you need to allow for diversity. take the first 10A then 30% of the remainder plus 5 A if you have a socket on the circuit.
I would have a double pole cooker switch with no 13amp socket on it. Cheers
our shower is on a 40a breaker with 2 isolation switches, one outside the shower room and a pull cord inside the shower room
Single ovens can be powered by a 13a plug. Often these would be wired on a separate circuit so you don't trip the fuse by using the oven, kettle, toaster, microwave and dishwasher at the same time. I have never seen 3 phase domestically in the UK, except if someone has a workshop. You would need a different meter and feed into the house. I understand the US does as you need it to have any decent power output from 110v.
Love that you used "spur" when you were explaining the US "branch" circuits :)
The 12 Amp rating is pretty simple. In a nutshell, for a continuous load, the circuit has to be able to carry 125% of that load. And 12/15 = 0.80 = 80%. So a 15 amp circuit can carry 15 amps for a short period of time, but shouldn't carry more than 12 amps continuously.
I can rember my Mother pluging in her iron into the light socket with an adaptor!
Not sure if this has been covered before. But the ring final circuit was invented to allow a 3KW heater to be moved room to room. 3KW or 3,000 watts at 240 volts is 12.5 amps. The ring final circuit allowed for electric heating which was going to be the number one heating source in the 40's as gas was old hat. As it happened electric heating turned out to be not that great but other electrical wonders did require an outlet for electricity. Therefore fuses came into being to protect items that didn't need 3KW to operate. The inventors of the ring final circuit never imagined televisions, computers, usb chargers or any of the other modern electrical items that we love so much. The ring final circuit is a throw back to simpler times.
Jason, I'll chime in on the 12-amp thing. It's part of our electrical code, and related to the trip curve of the circuit breakers we use.
As you likely know, an electric motor in a stall condition pulls approximately four metric craptons of current, and they are essentially stalled when you first turn them on. This is to say, an electric motor pulls a ton of current trying to start. If a 15-amp breaker tripped immediately at 16 amps, it would be impossible to start most electric motors. There are delays designed into the breakers (and fuse wires where used) to accommodate this.
In practice, a fifteen-amp breaker will take several hours to trip when loaded at, say, seventeen amps. That's okay though, because the wiring it's protected would also take a similarly-long time to actually become hot.
Our circuits are not designed to be fully loaded to 100% constantly, and in fact a breaker loaded this way will eventually trip. We define "continuous" loads as those devices that are likely to be operated for three hours or more at a time. These loads, in order to not trip the breakers they are attached to, are limited to 80% of the circuit rating. 80% of 20A is 16A, and 80% of 15A is... guess it... 12A.
Hair dryers, operated only for a few minutes at a time, are often rated to the full fifteen amps.
I don't know about vacuum cleaners. I've definitely seen some higher than 12 amps, and, really, if it takes three hours to vacuum your floor, you just need a smaller house.
Devices like electric space heaters with 15-amp plugs will most certainly be limited to 12 amps, legally.
At 5:20 Just checking: are there any older houses that _weren't_ built a long time ago?
In Japan they have really old temples they knock down and rebuild every 20 years.
Yes. Any house built before the most recently built house, is older than the most recently built house. Even if it was only finished yesturday :-)
A minor point - most UK houses don't have a 3-phase supply so, while many modern cookers can be configured for a 3-phase supply if one is available (there are link options in the terminal box of the cooker for this) they are usually supplied pre-configured for single phase operation.
It's interesting how the system is evolving - new installations now using RCBOs that give individual earth leakage as well as overload protection for each circuit off the consumer unit and consumer units now have to be metal (too many fires in plastic consumer unit apparently)
Hmm. Things have evolved again, beyond where I knew. Thanks for adding your two cents. It all adds up.
Hi Jason - I wonder if you are old enough to remember the early versions of the 13A plug that did not have the insulated skirts on the L and N pins? (I still keep coming across them on some of my ancient electrical stuff). I think I only made the mistake of wrapping my fingers under a plug far enough to get a zap once but that was enough.
I'm glad earth leakage trips are becoming commonplace. As a follower of the OSTAR races I was moved by the tragic death of Lizzie McMullen during preparations for the '76 race - something that an RCD, a common enough item even back then and costing only £5 today, would have prevented.
I don't remember them (I was born in 72). They may have existed around me, but they've been erased from my memory if that's the case. ha ha!
I love sailing - I used to follow the Volvo Ocean Race, but don't have the time for it these days.
I remember them, and was electrocuted by one as a 3 or 4 year old when I pulled the plug out the wall and put my little fingers in ... People like me (or the less lucky ones who didn't survive it ...) are the reason we have that insulation on the pins.
Apparently I was unharmed ;)
I obviously have some aptitude with things electrical since my next trick at the age of 6 or so was teaching my mother how to wire a fuse when one of the fuses blew because "I saw how Dad did it". Described how you screw it out, wrap the wire round, screw it in ...
Later, when we got a new cooker and I was about 12 or 13, I wired that in. Delivery guy said they couldn't wire it in, so I just started at it, went and pulled the fuse and began unwiring the old one. Delivery guy says, wide-eyed "Are you really going to let him do that?" and my mum said "Well, he seems to know what he's doing". Explained to the guy how it's just a plug except bigger, and pointed out where the live, neutral and earth go ... My dad checked it later and said it was fine.
Of course, when I bought a new cooker a few years ago, it said I needed a qualified electrician to install it. I did it :P
Guess what? I work in IT :D
Very interesting video, however I don't think you have hit on the real reason why the fuse is needed in the plug. I scrolled through the comments and maybe I missed it if someone else has made the same comment, if so sorry! But the reason I believe there is a fuse in the UK plugs is not to prevent the entire ring from going down. The reason is that, as you stated, the wire for the small appliances is rated at only say 3-5 amps, so an overload to say 10 or even 20 amps would not cause the 32A breaker to trip and the small wire would burn up and cause a fire. To protect the wire, the appliance, and everyone around there has to be a fuse. Basically, the breaker is for 32Amps, the wires to the sockets can presumably carry 2x26 amps (both sides of the ring), so the 32A protection is fine for the ring, but will not protect the appliance, you need the fuse at each plug. You are correct that it is the ring that creates this need for the fuse and nowhere else in the world do they use rings and thus don't need fuses in plugs, but the reason is not quite as you stated. Definitely would be interested if someone has a different perspective.
It's clear that the answer to the question in the title is that having a fuse in the plug allows different gauges of flex between the plug and the appliance to be used and always have a fuse which will blow before the flex overheats and causes a fire. This has nothing to do with the use of ring or radial circuits. The question that hasn't been answered is why isn't it also necessary on other systems which have 15A to 20A radial circuits? What's to stop anyone in the US or Germany plugging in a lamp with a 3A rated flex which will catch fire and burn down the house if a fault in the lamp draws 10A?
Theoretically the answer to that last question is that the appliance should contain a fuse matched to its cord but when did you last see a table lamp or a radio with its own internal fuse?
In Australia we use the radial system also but our usual household power outlets are rated at 10 amp the wiring in the walls is rated at 15 amp and the circuit breaker/fuse is typically rated at 8 amp. The reason for these ratings are simply that is an item plugged in to the wall shorts out the first thing that SHOULD drop is the breaker/fuse however before circuit breakers some people were lazy and would use heavier fuse wire to repair blown fuses to stop it blowing if it was just the overall load on the radial being greater than the fuse rating. so then as a secondary safety point the wall sockets were only rated at 10 amp so they would over heat and hopefully stop working before they caught fire. The wiring in the walls was the highest rating simply because that is the last place you want fire inside the walls themselves and because on a radial system it needs to carry all the current for the entire leg not just to a few sockets.
The down side to this is that when houses are being built cheaply often they will try to use as few circuit breakers as possible so you have one for lights one for power until they reach a possible radial draw of well in excess of 8 amp before they will put in a second breaker. In many cases you will end up with a house with 2 power breakers one that may have all wall sockets but for one or two rooms on it and the last room or two on the second breaker and if the draw on the first breaker reaches the limit it will drop out but the one room or two wont drop power at all. This would be easily solved by balancing the likely power draw over both breakers (say by putting the laundry and kitchen on different breakers and maybe then only putting half the sockets in each room on one breaker and rest on the second), but this is considered wasted time as they only put in second breaker if they have to.
Interesting video though as I had known you had fused plugs and used ring system but didnt know what the difference was and thought the fuse was simply a first point of failure point for ease of repair.
I didn't see an answer to your question in the comments, so here it is. NEC (national electric code) specifies that a circuit should not pull more than 80% of its rated load continuously. Which means the max continuous load on a 15 amp breaker is 12.5 amps. I am not an electrician so I don't claim anything I say is right. So a google search for "NEC 80% rule" is a good starting point to do your own research. I believe NEC 210.19 is the correct article.
I once attended a callout out to a farm that had a 3 phase supply.
The neutral broke on the powerpole of a delta wired system which resulted in 415 flowing down the live of the phase that the house had been wired to.
The fuses didn't protecting the circuits from that and every piece of electrical equiptment in the house and every wire in the wall was destroyed.
Thankfully thankfully the 100A incoming network fuse blew protecting the house from burning down !
Now that we live in rural France we can only dream of a 100A supply. The standard these days is 30 to 60A with more available and the inevitable three phase which can be foisted on you if for example you have a ground source heat pump or need too much amperage for the local transformer to cope with (think very rural). We only use radial circuits but the number of outlets per circuits and RCD's required make for a pretty good solution. I personally can't stand ring mains and think they should be phased out. However I do miss the British socket with a switch to isolate prior to unplugging... I just don't like the French earth pin sticking out of the socket...
The earth pin in the socket does mean you can easily clip an ESD strap to it.
The US National Electrical Code limits devices with a plug to 80% of the circuit's rated amperage. If a device needs to draw 15 amps on a 15-amp circuit, it needs to be hardwired. At a guess, this is because the plug introduces extra resistance to the circuit.
Eric Lloyd lol bullshit
Eric Lloyd
I'm not an electrician, but am familiar with electricity through my decades of hobbies involving electronics.
My guess is that the 80% standard is there to account for the fact that people don't like using appliances in the dark. 12A for appliances and 3A for the lights.
(This is really going to sound stupid)
If an electrical circuit is in the form of a ring, would not the whole circuit open if any of the sockets were to have no plug in them, and would not the appliance with the highest resistance receive the greatest share of that 230V line voltage?
Installing an electrical supply is an involved and technical task which is why for roughly 10 years now you have had to be qualified by law, even to work on your own house.
There are distinct advantages to a ring main, one of which is that every outlet is connected to the Consumer Unit via 2 cables, and therefore 2 earths!
This part of the regulation has recently been upgraded so that each earth cable now has it's own terminal behind the outlet, making it safer still.
Some houses were wired with radial circuits but this is discouraged even if it's not banned, I don't know if or when that might have happened.
The 12A appliance limitation may be part of *derating*. This is where the amp rating of a wire is reduced because of how many conductors are in a conduit, or because the wire passed through an area of very high temperature (attic). The theory of derating is that if there's some external factor which might stress the wiring in such a way as to reduce its ability to conduct its rated current safely, we reduce its current rating by a fixed percentage (and thereby reduce the load it can handle).
Only problem with the UK system is that if the whole house is on a "ring" circuit (with spurs), the segments of wire closest to the consumer unit will conduct a great deal more current than those in the middle of the ring.
It should also be noted that, because the UK voltage is roughly 230V, where the U.S. voltage is roughly 115V, the amperage draw for devices of comparable construction should be half of the US appliance rating. That is, a toaster in the US rated at 10 amps in the US should run at 5 amps in the UK. (Relates to the power equation: power = voltage times amperage.)
I used to be an electrician here in the States.
Heres a tip, use smaller tipped markers. Thanks for video
great vid that finally explains what a ring circuit is, i live in us and have been watching a ton of uk electrician videos its interesting how differently things are done i have to say the consumer units you guys have over there are way nicer than what we have
What you tend to get nowadays with RCDs and overcurrent breakers you tend to drop the entire circuit if there is a fault regardless. Unless there's a serious overcurrent situation, a 32A breaker tends to trip somewhat quicker than a 13A fuse blows and if there's ANY earth leakage at all, the RCD (which may precede the entire system, or just a set of breakers) trips and turns off anything it's connected to. It's fairly common to have one RCD for a set of 3 to 5 breakers (for example all socket circuits).
I’m not an electrician, but did study mains power fundamentals at college as a part of an electronics course. An overview of how power is distributed and how voltage is stepped down to safe levels. There are rather a lot of omissions in this video and some inaccuracies. I do know someone who is very highly qualified on the subject and would be more than happy to comprehensively let you know where you’ve gone wrong! I won’t tell him as it’ll be tortuous though! 😂
Nice description as I have always wondered about the fused plugs in the UK.
I live in NZ and we use the star configuration, known as Multi Earth Neutral. No fuses on our plugs. (Our plugs are the same as Australia.) Houses are usually single phase 230/240V @ 50Hz and standard plugs/sockets are rated at 10A.
High current appliances, like electric stoves, are wired using thicker cable (15Amp) direct to the appliance from the houses fuse box. (There can be a high current plug and socket used to make the appliance easily removeable.)
fun fact about the canadian/usa system, if 2 of the radials touch the voltage AND the amperage doubles
Can a 3 amp appliance draw 15 or 16 amps on a *radial* circuit without tripping the breaker?
If the circuit breaker fails (even on a radial circuit), the fuse in the plug is still better than nothing.
It's not entirely accurate that a fuse is required just because of the ring circuit. The purpose of the fuse is to protect the flexible cable from the plug to the appliance. In the case of a low-power device, like a table lamp, the flexible wire might only be rated at 3 or 5amps, and if it's damaged or the insulation is degraded it might carry sufficient current to overheat the cable under a fault condition yet not enough to trip the circuit breaker. That is an issue for outlets rated at anything significantly above the flexible wire rating - so it also applies to outlets on circuits rated at 10A, 15A or even higher in some areas.
Radial circuits in the UK aren't even limited to the 16A that is commonly seen. A 32A radial circuit to a kitchen is very common (and sometime 40A), and what's also common is for their to be a standard outlet on such a circuit. There is also nothing in the UK regulations that stops multiple sockets on a 32A radial. Indeed, many electricians prefer those to rings as they are simpler to test (and they make particular sense for a dedicated socket circuit for kitchens).
The simple fact is that it makes a lot of sense to have fuses in plugs with ratings suited to the flexible cabling, whatever the regime,
I used to work at Bill Switchgear The system absolutely brilliant.Cheers
Just need to point out most houses are single phase in the UK.
Also strange to see so many people get worked up by the fact that the UK does things differently from the rest of Europe.
It's legal to use radial circuits for sockets but electricians prefer ring circuits because they are superior and safer in several ways.
If we introduced regulations that forced us to use radial circuits we would be forcing ourselves to adopt a lower standard.
Regulations are there to provide a minimum standard not to lower them.
I imagine that other countries regard the the extra safety features as not worthwhile for the extra effort. Especially as components and appliances are of higher standards theses days.
But honestly most electricians in the UK are very comfortable with ring circuits and don't regard them as complicated or troublesome.
As for the fuse in the plug. We could eliminate it but why would we want to go the effort to remove a safety feature?
We already have lots of regulations and if we start introducing regulations that force us to adopt lower standards it defeats the purpose of having regulations.
Live and let live, don't get upset that people in different countries do things differently.
+David Lee
'It's legal to use radial circuits for sockets but electricians prefer ring circuits because they are superior and safer in several ways.'...why are ring circuits safer?
not safer, the Brits think they have a superior system, all systems are safe, the users are usually to blame. Something to do with education.
Yes, all systems are safe, but also have their flaws.
Mark William Mandigers It is safer in a number of ways. Multiple routes to Earth is one for instance. It can also be more cost effective requiring less copper per house. The UK plug has numerous safety features, something the plugs in some countries lack, as long as we buy decent quality plugs and not cheapo ones on fleabay that do not meet our strict standards. Do some research and you can easily see the strengths and weaknesses of the UK system, and you will soon also see the inherent problems in some of the other systems around the world. On the education front, tell that to a child who has been electrocuted by some of the really iffy systems out in the world. Just go to a hotel in Egypt that have an open element heated shower and you will see unsafe.
+phill luckhurst
'It is safer in a number of ways. Multiple routes to Earth is one for instance.'...Why?
I think the reason for limiting power to 12 amp for each device is because if what you have plugged in draws 15 amps on a 15 amp breaker then there is a greater chance of it tripping. Plus that breaker may still have to be able to provide power to lighter loads like a lamp for example.
Cookers can be anywhere from 29 to 30 amps but are on a 32amp trip. Here in the UK
VioletDragon Projects Modern all electric dual oven/hob units typically require more than 32A and require larger cross section cable and a 45A MCB. Such cookers should NOT be connected to a 32A feed!
+Jason Coulls
@ 2:00, those are transmission voltages, and in the UK they extend from 400 kv to 33 kv. The primary distribution network there extends from 33kv to 11kv, and secondary distribution begins at 415v. But I don't know why you got involved with that to explain why UK plug-tops are fused. The reason plug-tops are fused is the same reason any circuit or subcircuit is fused, to protect the circuit downstream of that fuse...irrespective of whether a ring or radial circuit is feeding into the fuse. Both ring and radials in the UK use a minimum of 2.5 mm sq cable, which is rated up to 27 amps...therefore if you're reducing the cable size to say 1.5mm sq (rated to 16 amps) when you plug an extension cord into the circuit, you need to protect that cord by introducing a fuse into its plug-top. That's the simple answer. Your explanation is overcomplicated, and quite frankly you're a good example of a little knowledge being a dangerous thing.
I enjoyed watching your video I like how the uk is wired vs the us it seems the uk 🇬🇧 is wired the way that if you overload a circuit only the one outlet will trip before anything else. I appreciate it 😎😎👍 I’m from the USA 🇺🇸 and have overloaded circuits before and the entire room loses power. Good information ℹ️
Still none the wiser. That malfunctioning US lamp could still draw many times its rating without tripping the breaker. A fused plug would seem a sensible idea whatever the system, enabling a direct match with the rating of the appliance.
15A is the maximum current, but regulations say you shouldn't run it continuously at that current. I suspect that's why you see 12A on many appliances. For instance, 15A X 120V = 1800W. However, most appliances are rated between 1400-1500W because that power level is considered safe for continuous use.
We have both single and three phase available to residential consumers here in Greece. For single family homes they tend to push one for three phase power but that mainly benefits the electric company which charges more for 3 phase service. Most kitchen ranges can be wired for 3phase to help balance the load better instead of piling up heavy draw appliances on a single phase. Another issue being enforced now in Greece is the testing of the wiring and breakers in residential units every 14 years and commercial and retail locations every year. The latter not enforced if electric service has not changed due to new renters or new businesses. That is bound to change as the government finds new ways of draining the pockets of the people here.
I suspect the 12.0 amp limit on consumer items is simply because the manufacturer doesn't want to have to add a very strong notice saying this device must have an individual circuit breaker, consumers want to plug their vacuums into any Outlet that's convenient to them so one with an extra 3 amps wiggle room is perfect
most sensible electricians tend NOT to use ring mains, as radial circuits are much easier to test, and fault find and if the circuit fails at one point after that point the circuit will be dead .Not so in a ring main.. so in a kitchen instead of a ring main. 2 or 3 25 amp radial circuits should be installed giving a system capacity of 50- 75 amps in the kitchen , and also if ,due to a fault you lose one circuit you still have power in that area. A ring main is the ONLY circuit that still works when it is faulty.and are easily overloaded if damaged.... and you wont know....
In the US, you can only draw 80% of the rated breaker current continuously. Therefore, 12 amps is 80% of 15 amps. One can pull 15 amps for some duration before the breaker heats up and will trip. At 80% continuous amp draw, the circuit is good indefinitely.
In the USA most homes have 4 to a maximum of 6 outlets (120V 15A) per room. Kitchens have dedicated circuits for the refrigerator (120V 20A) and stove (240V 30A). The breaker panel "consumer unit" in a typical home is rated 100A feeding the home with 15, 20 and 30 amp breakers with the majority being 15A breakers. if for any reason there is a short in say that lamp, the breaker trips shutting down a maximum of 6 devices. There is logic to shut down the area as to not cause damage to another device like a TV or computer located in or near said outlet. Also this idea is easier to add or change circuits without disrupting the rest of the home something not possible in a ring circuit.
Now on to answer you question about appliances under to 15A rating . My vacuum cleaner is rated at 8A and a tea kettle rated at 12A. Manufactures are creating more efficient appliances so that we can use more at the same time. For instance in the kitchen, I can use a tea kettle toaster and microwave all at the same time because the circuit is rated at 20A while other parts of the home (bedroom, living room, dining room......) are at a 15A circuit. My entertainment center is dedicated to one 20A circuit.
As far as fuse in a plug, yes we have them available as well as plug strips with breaker and fuse protection built in. Along with GFCI (Ground Fault Circuit Interrupter) and child safe outlets have been in the USA for more than 25 years.
Maybe now you can get an understanding why we do it this way.
I actually think (personally) that the radial circuit is way better. The ring circuit idea is a daft relic that should be consigned to history.
The idea of the ring circuit is that the load is equal across the whole circuit but much more difficult to add or rework. On our system the load equalization is done in the main panel by distributing breaker amperage evenly or as close to equal on the two main legs. The neutral is constant across the entire home as is the earth but that is fed directly to the earth. My home was built early 1930's and used our relic "knob and tube wiring" (look it up) method with only feed and neutral wires and no earth. Many homes still exist that used this wiring but I upgraded my home many years ago.
By the way your videos are a helpful explanation as well as entertaining. I'm also an IT guy but on the infrastructure side and electric is also part of my job.
The ring circuit is a wartime relic, but it’s pretty easy to add to it - you can just take a spur off a socket on the ring. Each ring main, which requires surprisingly little copper, and is run like a radial but with a return, can supply about 7.5kW. That’s pretty good.
Oh I know Knob & Tube.... Each time I've bought a new house or moved, it's been top of my list to look for. Even the house I'm in now has a few dead circuits from when it was first built that was the next thing after the knob & tube...
I grew up in the UK with Round pin plugs and sockets.
12 amp devices because the wire's actually technically good for 25 amps and a 15amp breaker won't pop when the device pulls a surge at start-up since the system is ground/common based at 115/125/105/130v... it makes it a universal standard for use across much of north america. You can actually wire 20 amp circuits using special outlets and such legally (or just put a 20A on the breaker panel) but for the most part the outlets themselves are the limiting factor since 12Ax125v=1500w and THAT is the standard used. Gets a little weird and there's tons of variances but if you're dumb enough to buy a power supply or device in the US that uses more than 1500w it's either going to be 240v or require the special outlet.
There used to be quite a few standards including a 20a three blade rotating plug for kitchen appliances like oil fryers and I remember a 2ph 240v my dad showed me which had five blades and had to be bolted into the outlet AFTER it was turned 18° but I never found out what it was used for - probably shop equipment or something.
But the standard here is 12A continuous draw and 15a peak load and the breakers toss at about 17a@125v unless they're made by Federal Pacific Electric in which case they fuse on and you die.
"I just made the arrow worse."
Thanks for the laugh though.
I recall in the early 70s we had Round three pin plugs/sockets and the plugs were rated at 15amp and did not have fuses, UK. I believe they are still in use today.
No, the round pin plugs would have been only in old houses in the 1970s. The square pin fused plugs came in in 1947, but it took many years before all old houses were updated.
An excellent video. But here in the UK it is very rare to have a three phase supply within a domestic property. Household cookers do not need that sort of connection. In my house a large and a small oven run to a (correction) 20 amp breaker on single phase.
That bit about three phase residential power struck me as strange. I'm betting he's using the term to mean something other than three separate sine waves each leading the other by 120 degrees. Three-phase power is only used in commercial and industrial installations here in the USA, and it would strike me as odd for the UK to be different; there's just not much need for big three phase motors in the home.
Maybe he's using it to mean a power supply from a center-tapped transformer. In the USA most homes get three-wire power feeds, two hots and one neutral (a center tap bonded to earth). The voltage between the two hot lines is 240; the voltage between either hot and neutral is 120. The 240 volt circuits are used for high-current appliances like clothes dryers and kitchen ranges. The two hot lines are effectively two phase power, 180 degrees phase difference. Do some UK homes get something analogous with both 220 and 440 volts available for circuits?
Yeah Domestic properties in the UK usually only have single phase 230V supply, although the cables in the street have all three phases, so it is likely your next-door neighbour will be on a different phase to you, which, I am told, is why you shouldn't share extension cables over a garden fence. I believe in the US you have two 120V phases domestically, so you can have 240V for larger appliances?
That is correct. The lower voltage used in North America is yet another historical relic. A voltage around 220-240 is actually pretty close to optimal for a mains voltage with current technology. It's a good compromise between safety (lower voltages are safer), the need for insulation (lower voltage = less need to worry about insulation and arcing = lower costs), and metal costs for wires (higher voltage = lower current for a given power = less money spent on copper).
With electrical technology circa 1885, however, a voltage around 110 was optimal, because electricity then was used almost exclusively for lighting, and with the technology at the time, it was cheapest to manufacture carbon-filament incandescent bulbs at wattages commonly needed for interior illumination at that voltage. That cost advantage for incandescent bulb manufacture hasn't existed in over a century (and incandescent bulbs themselves are now mostly historical relics), but North America is thoroughly locked into 120 volts.
The three-wire electrical feeds became common in the post-WWII years as a way to allow houses to have high-current appliances without using expensive super-thick wires or requiring an extremely disruptive doubling of the standard mains voltage.
We did have a uk house that had 3 phase, we had to get it installed because my partner is Italian and wanted a huge cooking hob. Admittedly it could be wired to run on single phase but in that instance it would reduce the number of rings that could be used together automatically. 3 phase meant there was less delay for the pasta, a top quality investment :-). It also proved to be awesome when we sold the house as the guy who bought it in only came to look at it because 3 phase was listed in the property details and he wanted to run a kick ass milling machine in the garage.
I suspect the answer to the 12A question is that the wire from the plug to the applience is probably something like 18gauge wire which has a lower ampacity (rating).
18 gauge is not used in any wiring in the USA. The minimum gauge is solid copper 14awg wire that can carry 20 amps safely but our laws limit to only carry 15 amps.
Harry Lanza if that is 120v then that would explain your need for more amps we have just 240 more volts less amps we can run 3kw off any standard plug in the house were as having 120 for some products and 240 for others seams silly to me
Harry Lanza Right, but I thought he was referring to the cord that one plugs in the receptacle.
He said "wire from the plug to the appliance" which can be less than 14AWG, and always stranded instead of solid.
It's 1.5mm cable which is rated at 18amps it's overated on purpose there is a British standard maximum sized cable to be used in a British plus top is 1.5mm BS1363...
As mentioned, rings go back to the war era and have not been standard practice in the UK for some time.
I can see some advantages to the UK system; your radio blows a fuse but your lamp stays on. However, most North American appliances have their fuses internal to the unit itself instead of in the plug, so effectively we have the same thing, just a little further along the line. Advantage to the UK fused plug method, you MUST unplug it in order to change the fuse; it offers that layer of safety. While most NA appliances have their fuses in special access sockets, it is still possible to encounter current if the unit has not been unplugged.
As for the vacuum cleaners etc. that are hyped as 12 amps even though the circuits are 15, this is more a selling point as to the power and torque (the sucking power, if you will) of the unit's motor. And you wouldn't want unit too close to the circuit limit of 15 amps since the couple extra amps drawn at startup would blow the circuit every time and you'd never get your work done! Not to mention the small fortune in fuses. Of course circuit breakers save money. LOL. So 12A is the logical upper limit for vacuum cleaner motors.
most manufacturers 'embellish' the marketing speak of their products power by quoting the peak load that the appliance draws... this is often an instantaneous load at start up (especially for electrical motors). So its not the continuous draw load. You can see this quite easily if you look at the advertising for the Wattage (or Horse power) quoted for a product and then work back from 230v (uk) or (110v (USA) to calculate the current draw, and you'll find its simply not possible. In soe areas such as power tools and machinery this has become a Top Trumps type marketing war which is plainly nonsense but shifts units off shelves when the consumer has a mind set of "bigger is better"
Don, Most appliances here also have an internal fuse. However ring circuits go back to 1948. At that time, appliances were not the low power electronic devices we have now. Lamps were an exception (although to be fair incandescent lamps have a fuse - the bulb). The idea of a 3kW electric fire being able to draw 9 kW through its appliance flex due to a fault is rather frightening as it wouldn't be able to take 3 times overload. Also bear in mind that originally consumer units used fuses (and indeed many houses in the UK still have rewireable fuses to this day). Fuses can take a fairly large overload before they blow, so a 30A fuse probably won't blow at 35A. Having a 13A fuse, that definitely would blow at 20A therefore solves this issue. A 32A breaker also probably won't blow immediately at 35A, as it would take a while for the bi-metallic strip to heat (although a 0A to 35A surge would almost certainly trip the breaker immediately as the other form of overcurrent protection - the solenoid would activate).
In its own way, we could go back to radial circuits now and use lower amp breakers, however we would still be using BS1363 plugs and socket outlets. Because of that they would all be fused. Not only that, but even if the regs changed tomorrow, there are installations that will be running with rings for decades.
The design of BS1363 only has the one flaw. They bloody hurt when you step on them in the dark.
Some of your wall sockets in the uk also contain fueses. So they are double safe.
I remember my relatively small studio unit in England had something like 7 circuits?
Though literally everything was electric.
So we had a circuit for the oven, and one for hot water, both of which were something like 40 amps.
Then there were at least two lighting and 3 power circuits.
And then a master breaker off something like 70 amps.
I do in fact believe that there was evidence the unit had two-phase power running into it as well.
(given there was a commercial property downstairs and 4 residential units in the two upper floors, I suspect maybe the commercial unit had access to full 3 phase power, even though the shop in it probably wouldn't need that, while the residential units were all using different sets of 2 out of 3 phases. Who really knows, honestly. XD)
Point is there were a lot of power points, and a lot of circuit breakers for what was actually quite a small space.
By comparison the larger one bedroom ground floor unit I have now in Australia seems to have just 3 circuits in total, though in this case the oven, hot water and a heater are all gas, rather than electric like in the UK unit...
the reason for the limit is because of surge amps. allow me to explain, in a North American house we generally use 15 amp breakers but often times in a condition of particularly high load an appliance rated for 15 amps will throw the circuit for no other reason than it has exceeded the maximum capacity of the breaker and home wiring so by rating devices at 12 amps even under excessive load the breaker will not be tripped unnecessarily. Also unfortunately our appliances do not run on true three phase because each line is not out of phase in frequency in true 3 phase there are 3 distinct pulses of electricity 120 degrees out of phase of each other from separate generator windings. Our 240 volt appliances run on 2 separate 120 volt breakers coming from the same central breaker and mains line wired in series to double voltage.
Also, many appliances have fuses inside their power supplies instead of mounted in the cord
Additionally, in my home anyways and every other US house I have been to there are 4+ breakers per level for about 1000 sq ft levels
In Australia we run on uk power but our power system is based on the usa otherwise we would have uk wall sockets . looking at my fuse box this is what i found -
2 power circuits = 1 rcd on each power circuit rated at 10 amp - lighting circuit = 1 rcd at rated at 8 amp . when it comes to business i believe all thats done is the 10amp power power circuit are rcds/breakers are changed to 15amp.
When did the UK change over to flat pin plugs and sockets?
1947
en.wikipedia.org/wiki/AC_power_plugs_and_sockets:_British_and_related_types#BS_1363_three-pin_(rectangular)_plugs_and_sockets
The 12A issue: most consumer grade vacuums in Canada use SJ / SJW type wire of the 2 conductor 17ga or 2 conductor 18ga variety. Based on Underwriters Labs current-carrying ratings, the 17ga hits roughly around the 12A limit for runs of 0 to 50 feet.
The 18ga technically shouldn't be used at all, since it tops out at about 10A max capacity and if you're unlucky enough to have a vacuum that draws more than that, you WILL find the cord getting quite warm during constant service (yes, even with a 12A vacuum). Anything over 5-10 minutes runtime should be viewed with caution. (This is also why your detachable black PC 110/120v cords all have that 10A max rating stamped on them, they're 18ga albeit a much shorter run, and are actually correctly labeled for their application.)
With respect to vacuums, however, I've seen firsthand the danger this poses, as in the past I've witnessed 12-foot and 20-foot 2/18 cords ignite when they had 12A running through them. Don't believe the sticker if those piddly little things claim to be able to handle 13A or 15A.
Oh yeah, and DON'T let prongs get dirty or corroded, you'll have an even bigger fire hazard on your hands. :P
There’s a slight confusion here - a UK consumer unit is usually rated to 100A, while the ring circuit MCB/breaker is 32A.
A fuse can also break the circuit in the event of an earth fault, but this is not its primary function. An RCD and/or MCB is much quicker.
Thanks. There's a number of points where my wording was a bit wrong. I realized after uploading, that the fiery lamp wire comment mentioned that the lamp was on a 3amp fuse, when I meant to say low rated wire, then say the problem can be avoided by putting in the fuse. Doh!
You need a serious earth fault to trip a fuse or MCB, which mostly never occur unless you have a short to earth.
Also a fast blow fuse can be as fast as 10ms, I don't think a MCB can be much faster.
The thought of waiting for a fuse or MCB to protect me from a leak to earth leaves me frazzled...
Nice tutorial,. I'm in Canada. It's a safety margin. Dont want the breaker tripping all the time. For example a vacuum. When the vacuum is started there is a power spike. At 12 amps the breaker can tolerate it because it's quick. If the vacuum pulled 15 the margin is not there and would pop the breaker.
Just for fun, that immediate high current drain on motor loads is called "locked rotor amps" (LRA). On large equipment where this is important, there is a panel which specifies the running and LRA, along with voltage and such. It is called locked rotor amps because if you started such a motor but locked it down so the rotor couldn't turn, this is the load you'd get. But, free to spin, a motor only draws that for a short duration on start-up.
So I guess to restate: circuits in the UK are commonly 240v*32a=7.68kw max at the breaker, which if something shorts is easily enough to start a fire without tripping the breaker, made practical in terms of wire gauge by connecting the run at both ends (and reduced transmission loss from lower current for the same wattage because of the voltage). While non-appliance circuits in the US are 120v*15A=1800kw max at the breaker and so having less less ability to start a fire if there's a short, and reduced ability to arc because of the lower voltage.
If something shorts then the breaker will trip in a fraction of a second before there is any danger of the wire overheating.this is because a short will allow a much larger current to flow, exceeding the 32A the breaker is designed to allow through
Dang, you almost had it right. Your math's off by a few orders of magnitude, though. 120v x 15a is 1800w (or 1.8kw) , not 1800kw.
Maybe you should also talk about the distribution voltages within the building? USA = 110V UK = 240V, Australia = 240V with yet another type of plug and socket?
Some homes in the UK have radial circuits. For some reason my flat has a ring final circuit, but both sockets in my bedroom have their own 16 amp breaker because they are on their own radial circuits, for some reason.
depends on the need and ease of wiring at the time, if your flat was converted from a house at some point, or has been rewired in the last 10 years or so, its likely that the landlord/agency didnt want the hassle of setting up a full ring-main for 2 plugs, for example, its just easier to set up a radial for each room and really has no effect on the operation of appliances
I live in a block of flats that was built around the very late 1960's/early 70's. The hallway socket, the two in the lounge and the one's in the kitchen appear to be on a ring, but the two in the bedroom both have their very own breaker.
I'm not sure about some of the stuff you said e.g. 32A consumer units - there's several 32A circuits in a CU, along with other amperage circuits for lights etc & 3 phase to cookers (which I wish was the case as I could run my tools on it!). I *think* (IT engineer here also ;) that the main reason for the fuse is for when you get a short that DOESN'T draw the full 32A. In this case the circuit breaker (RCB) in the CU won't trip but the fuse in the plug WILL blow. With 15A circuits, this difference between operating amperage and consumer unit breaker amperage is much less, so there's less need for a fuse (although it will always help, having an extra layer of safety). I think this is what you were getting at whilst worrying more about your drawing skills, yes? :)
Keep up the good work expanding the empire over there and send back some maple syrup for HM the Queen. :)
And agreed that UK plugs are the best (except at nights)
A little knowledge is a dangerous thing. UK and Ireland are almost identical regulations. Consumer units are normally minimum 63 amp to 100 amp depending on size of house. Cookers are not supplied with 3 phase 400volt as standard. Cookers. Immersion units and showers are supplied on a separate Single phase dedicated ring normally with 32 amp mcb as protection. The fuses in plugs are to prevent fire in appliance by short circuit on ring main, although mcb and even older elcb will most likely trip first.
You kept saying the consumer unit is rated at 32 amps. The circuit breaker protecting the ring final circuit is rated at 32A not the consumer unit. there may be several 32A circuits (say an upstairs, a downstairs and a kitchen ring, then several 6A lighting circuits, maybe another 6A circuit for smoke alarms and intruder alarm, A cooker circuit which may be 40A, a shower circuit, etc etc. the 32A ring you mention is just one of many in the consumer unit (sometimes referred to as the fusebox)
a fused plus is safer, and easier to fix.... but in the UK how does one household run on a 32Amp service when you have an all electric kitchen? in the US our ranges can pull up to 50 Amps at 240Volts.... and the clothes dryers about 25 amps.... you combine those with the rest of the house and you'd be blowing your main fuse in the UK.... how do the newer homes in the UK handle this? here in the US, our "CU" is rated at 200 amps...
He got a bit muddled as a normal socket rings on the CU will be rated 32A, but the CU will be higher depending on the size of the house. Someone else in the comments said 100A is the most common for regular sized houses now days, but I honestly have no idea.
Most ovens don't have plugs. You wire them into a junction box that is on its own ring (possibly along with a seperate hob, and a single socket) conected to an easily accesible, bright red switch nearby, that sits in for the socket switch we would normally have.
Small houses / appartments may have a plug in oven, but then the kitchen will have its own ring. There wont be space for more than one other large aplience in the kitchen, but in my wifes old flat she could blow the main fuse by running the oven, the washing machine, the kettle, the microwave and the hoover, all at the same time.
I'm building a house in Jamaica. I'm thinking of putting UK plug sockets instead of the US ones so my computer won't explode. Will this work?
Sometimes, the wiring itself can go wrong, so you need to cut electricity to an entire spur. I had an electrical outlet short out and melt without having anything plugged into it.
Cookers are not three phase in the UK. Most UK houses are single phase.
Easiest thing to do is just split those ring circuits into two radials, and put properly rated circuit breakers into the consumer unit for each one.
How is that any easier than simply leaving it as it is which is just fine?
The 12/15A question in the US is due to breakers only being rated for 80% continous load. Not like in Europe where fuses are rated for 100% continous load.
15A x 0.8 = 12A.
You have the same issue with charging EVs. You have to have a 50A breaker to set up 40A charging, since 50 x 0.8 = 40.
Rather odd for a European. :-)
Nice one Jason.
I did NOT know that my heater/electric hob and oven (I use all gas, but still) ... were on a three-phase circuit. In fact, I'm fairly certain they're not.
Is it not the case that the CU is fed with three-phase? Then two 32A phases get split to power the two separate ring mains (for upstairs and downstairs) ... and the third phase goes to the kitchen to give the big appliances their own 32A circuit?
This would appear to make more sense, as I have no 5-pin triple-phase connections anywhere in my home, nor have I ever seen any in domestic situations.
While I'm at it (and I know you're not an electrician, but still, it's nice to ponder)
I'm sure you'd agree that Live and Neutral are both Hot, yes?
And the Earth is NOT a return line ... so L&N (being AC) must serve as each others return, each serving half of the cycle? ... and, if that's the case they're necessarily 180 degrees out of phase.
So, surely that's a kind of 2-phase system ... and surely both phases would need to be 115-120v, so that out-of-phase they provide 230v-240v peak-to-peak ?
So, are we on a US system, just terminated differently ?
>scratches head<
Furthermore, can the US system provide 220v with alternative termination? I hear that machine shops over there use 220-240v ... so that would be a neat way to provide it - and would make us a lot closer, electrically, with our cousins over the pond.
Especially since I just learned that many building sites in the UK use 110v tools and equipment, to minimise risk of death in those situations where electricity is used outdoors and in high risk environments... I never knew that : ) ... but it would make sense if our domestic supply was really a split phase 115v acting against each other to provide 230v
Ain't mains electricity f'ing confusing : )))) Best left to the experts, always : )
Don't feel you need to struggle for an answer, I'm just unloading my curiosity.
North American outlets are regulated by the NEMA standard which calls for a 20% safety margin.
So a 15A receptacle should never have an appliance plugged in that draws more than 12A.
As far as I am aware, the fuses in UK wiring is always to protect the circuit.
Why do we use a higher voltage than America?
The ring circuit is old and outdated. Yes, it had it's place in history but in the present it is just easier for electricians to just run one wire through the house as opposed to running one wire to each room. With the advent of RCD breakers it's a safe enough system. I have lived in the UK for 20 years total and I've rarely known anyone to blow a fuse in their plugs but many people losing the entire ring because the RCD breaker has popped.
I dislike the video because you did not say the CB will trip in case of the lamp fault in the ring circuit. Instead you said that the wire will be on fire, what the CB does if it let the short circuit happen and does not trip?
in US they limit a lot electronics to 12 or 13 amps just to protect the old outdated house wiring that is in aluminum instead of copper. plus we have 99% of outlets in pair outputs so people tend to plug multiple things in same outlet location, on top of that the outlet might have a neighbor outlet on same breaker/wire so there might be something there too. in new construction in 95% of the time I put 20 am barkers with 12 gauge wire and not more than 2 outlet locations in same wire/breaker, but knowing how American people dont know electricity, I like to put 1 outlet location per breaker
Ivan Kishov Jeezuz!! One MCB per outlet!!?? I would have needed an industrial consumer unit/ fuse box for the kitchen alone in a house I used to own ... 27 outlets ... Just in the kitchen. THAT'S why a ring main with fused plugs is so much better. ONE breaker covered ALL those sockets ... Last lived there 28 years ago ... The house is still standing
It depends. USA consumers dont want fuses, more then that, in some areas of USA if you come to a house that have fuse system, you must not touch it or overhaul it to new standart.
15 amp circuits huh.
That's a lot less power at 110 volts than it is at 230
I'd have to draw 3 kilowatts to overload a 15 amp circuit, but at half the voltage that's only 1.5 kilowatts.
I think the worst part of 110 volt systems is that you very quickly run into needing a 240 volt or higher circuit anyway for various appliances...
Then again in Europe I was being electrocuted repeatedly by the metal casing of my friend's computer.
Why? Because while the computer should technically have been earthed, many household wiring circuits, especially in older properties have no ground wire.
Similarly, the socket design is such that there's usually not much stopping you putting an earthed plug into a socket with no earth. (you can tell the socket doesn't have ground/earth because the pins for it are missing.)
That really was pretty dubious, I have to say...
I don't know about that "very quickly." We simply don't have a need for many appliances over 1500W.
Our "cookers" (stoves/ovens), electric dryers, electric water heaters, and permanent electric space heating does usually require 240V, and whole-house air conditioning systems. For everything you'd normally plug/unplug and come in frequent direct contact with, 120V and its associated 1800W (1500W continuous) limit is quite sufficient.
Nice try in explaining but not completely accurate. There is no 3 phases to domestic property in the UK. It is all single phase and neutral so your electric cooker is also single phase 240vac and protected by a 40A breaker and usually a 100A or 63A ELCB (Earth Leakage Circuit Breaker) or properly referred to as an RCD (Residual Current Device) or RCCB (Residual Current Circuit Breaker) which services the ring main circuuts as well as cooker and electric showers and boilers.
The ring main ensures that there is very little voltage drop when you plug in a heavy load like a kettle or toaster as well as distributing the load more evenly. The 2.5mm sq wires they use is rated at 26A but is more than capable of carrying 32A even for long periods but might get slightly warm. Some larger houses that are built nowadays will use 4.0mm sq which is rated at 32A.
All appliances come with a cable or flexible cord that is rated at 13A. This is the current limit of the plug and appliances that can be plugged in. The appliance however will have smaller current carrying capacities and so are best protected from short circuit with a fuse that is rated for the size of conductkrs in the appliance. This will prevent the appliance from overheating and catching on fire rather than the flexible cable. Domestic fuse sizes are rated at 1A, 3A, 5A, 10A and 13A si it is important to fit the correct size fuse for maximum protection.
So the plug has a built-in surge protector if im right?
No, that is not surge protection. It's protection against too much current going through the wire.
I'm really sorry, but this. Idea simply confuses what is quite a simple subject. Electricity can be distributed by rings or spurs, whichever is the most convenient. The entire point is that each home has a maximum amount of electricity available, and you need to get it to where it is needed. In UK homes we have spurs to fixed heavy loads -cookers, permanent heaters, washing machines, and then we provide rings where lower power devices can be connected randomly where it's convenient. The ring is an efficient way of providing up to 32 Amps of current. One for the ground floor maybe, one for upstairs? Before we used rings, where each plug is protected, we used a system very similar to the US system where each socket outlet went back to the fuse box, and of course we had one fuse per circuit. Rings are convenient, and electricity distribution companies use them to connect their substations. They're simply an efficient way of doing it. Forget the daft numbers. 13a mains has proven to be safe and fits in well with our building system. It's not better or worse, just different. As for all this stuff about cable sizes, it's all down to what's called diversity. A 13A double outlet has two routes back to the consumer unit and shares the load. Fuses in plugs prevent more than 13A being drawn, which is the socket rating, only 32A is available from the breaker in the consumer unit. All these features allow trip free living. If your system trips under everyday use, you need an extra ring. It's so simple there is no need for confusion.
We also need to not talk about multiple phases. Only a very, very few homes have 3 phase power, so adding that confuses, and the reason is safety. Three phase goes past your house, but each home just picks up one of them for 240V supply. 415V from our 3 Phase is simply unnecessary, and we don't do it. Older homes had a maximum load at the fuse box of only 45A, then it went up to 60A,a and now 100A is common at the consumer unit BUT few homes will every attempt to come close to using this amount of electricity because there's no need and we couldn't afford it!
In my humble view, the is no need to make rings mains as complicated as this. They are exactly the same as the ring we use to supply our hot water to radiators all over the house. We don't return each radiator to the boiler, unless we use microbore, when it becomes like the radial systems US and Europe prefer.
Minor clarification here. In the US, *each* plug doesn't run all the way back to the panel ("consumer unit"). Each plug is on a "branch circuit", and there are a certain number of receptacles allowed per circuit based on the wiring (size) in use and the size of the circuit breaker at the panel. Typical branch circuits are rated at 15 amps (#14 wire) or 20 amps (#12 wire). For heavier load devices (like cooking stoves and air conditioners), larger wiring and breakers are used, but all breakers are housed in the panel. There is a main breaker in the panel, usually rated at 100 or 200 amps. Houses are almost exclusively single phase 115-125 volts. Commercial installations usually are served with 3 phase power and panels ranging from 200 amps and up (though anything above 200 amp typically involves a "cabinet" rather than a "panel").
I like the UK idea of putting fuses in plugs. It would increase the safety of electrical installations, and prevent whole circuits being blown when a single device is overloaded. But alas, if it's not in the National Electrical Code (NEC), it will not happen. (See my earlier comments on a different thread about the NEC.)
Some Christmas lights in America have fuses that are replaceable.
Cookers 3 phase? That's a new one on me. As far as I'm aware, only a single phase is delivered to the CU from the street transformer. The next phase goes to the next house, and so on. So how can a cooker be 3 phase?
Tim Long well it's true that people are using the word phase in the wrong way, a cooker, or I think you mean stove or oven, could easily be three phase. The elements are just a resistor and I don't think I can explain what phases look like when joined together if you don't know what LOL. 60 or 50 cycle, when the first phase is in between directions and at neutral, the second phase is just starting in the opposite direction so you have twice the power, in three phase they are 90 degrees out of phase so you never reach a neutral electrical charge and the net result is greatly increased! If you never seen a waveform and you can't picture in your head, don't worry about it.
I used to force German plugs into UK power outlets, worked fine
tomtom vicky i
Doing this damages both the plug and socket. Besides pushing a 2.5 amp plug into a 32 amp ring main is not terribly smart
Lots of kit gets plugged into 13A outlets with the adaptors that come with shavers (which are usually fused internally at 2A) or with the Chinese 'deathdapters' - which allow US flat two pin and EU round 2 pin plugs to be connected. They're truly dodgy devices and should really be banned - but they're a fact of life. An appliance fault would indeed have access to 32A of current - but the weak link on lower current demand small items is the cable - and the usual result is the cheap ones fail at some point where the conductor is weak, and they burn out - sometimes spectacularly - but luckily often this happens with no outwards sign - as lots of imported equipment has very underrated conductors - with hardly any copper - kind of like having a 3 foot long fuse!
Never thought about it like that, done it for almost 20 years, especially the slim Euro plugs worked well (well, I used UK plugs more, of course). check it out: www.digitpress.com/room-of-doom/cm/displayimage.php?pid=4151&fullsize=1
In the netherlands We have fuses in most of our sockets.
Uhhhh... The voltage ranges for distribution here don't really make a lot of sense. Low-voltage distribution that you might expect at your house for instance(right before the transformer that gives you your 120/240V power in the U.S.), can range from about 2.77kV to 14.4kV (open wye voltages, for delta configuration that range would be 4.8kV to 24.9kV) Then there's high voltage distribution at around 23kV, 46kV, and 138kV (open wye configuration here), and then you have transmission where you would see the high voltages over 200kV as you mentioned. Some of these ranges may be specific to companies in my area, but generally speaking those are the ranges you will see.
You need to invest in a white board so you can easily correct mistakes lol 😁
That would be an expensive investment for me - ha ha! - I think I've done one video like this... this one!
Yea, i gathered that an old house was built a long time ago!
I love these videos
some interesting vlogs, 250th subscriber :)
Thank you! I'm still amazed that having been making and practicing vlog videos for a year, things are suddenly blowing up now. I did my "100th vlog" just in November, and only had 32 subscribers! This is insane how fast things are going suddenly!
I just watched your recent vlog explaining that, I'm an IT tech but always had an interest in how apps are made on various devices. Hope the boom continues!
Cool. Tomorrow's vlog (filming it shortly) is on some funny code that Apple computers run.
I wonder how many times those small fuses are the cause of a fire themselves.
These fuse are sand filled and can handle huge currents without rupturing the casing.
The fuse housings are often dodgy and can get hot when they don't make good contact.
Only if you buy plugs that are not up to standard, or have been damaged.
32 amps for today's lighting and appliances? You must be talking about homes in Timbuktu.
Jason, Some of the junk splooged out from communist China to the U.S. have these damn dumb fuses. Yesterday I bought a new fan, and yes it has a plug fuse and no supply of extra fuses.I'm cheap and run alot of old fans and other 40 to 60 yr. old appliances which have no plug fuse. What is your opinion if I snipped off the plug with a fuse and put on conventional plug without a fuse? Asking for your opinion as one nonelectrician to another.
correction(from an educaited electrician in Denmark):
its not Kvolt, its just Volt, else in your exampel you'll have 270 000Volt, wich is not the case, cant say much about the U.S other than they have 120V between a fase an Neutral. The U.K(and almost all of EU) how ever has 230-245V between a fase and neutral, and 400V between a fase and a different fase. U.K is also 50Hz, U.S is 60Hz
Here's the UK parlimentary doc (www.parliament.uk/documents/post/pn163.pdf). Note the 400kV and 275kV.
Jason Coulls link dosn't work.
But look jason, if it was that high voltage then you would be fryed just by standing 5m away. I think you're mixing something together that you've read about the grid power, connecting cities together. I work as an electrician every day.
Not knowing what you talk about is one thing, but being stubborn when some one is friendly and tryes to correct you, is a completely diffrent thing and in this field, informing ppl wrong about this is really bad, because they might then end up with a bad accident.
1) just remove the right paren that RUclips made part of the link. 2) Its the transmission voltage. You understand that right? You're talking about the socket in the house?
Jason Coulls yes im talking about the voltage going into your fuse box in your house and there for also the sockets, wich is what you where showing and talking about in this video, it makes no sense to talk about the transmission voltage, when your point is to explain why U.K plugs are the way they are, if you think the transmission voltage matters when talking about the house instalation, then i would politely advice you to stick to your softwhere programming.
OK. This is the last I'm saying on the matter. In the same way people might talk about the sun before talking about the earth, I talked about the transmission before talking about the residential situation.
Jason, thanks for the interesting plugs/electricity supply videos. You said that UK cookers are supplied with a radial 3-phase circuit - this is (generally) not true, almost all UK domestic supplies are single phase, unless you have a very big house! You are correct that electric cookers (and electric showers) are connected on a separate radial circuit as these are rated for much higher current.
Water heaters is another one often with their own radial circuit at least when the electricity is actually supplying the heating element as opposed to just supplying pumps and similar as in gas boilers.
His information is just out of date. That was the standard back when the retangular pin plugs came in, and remained the most common setup till when the number of houses with single phase cookers out numbered 3phase, probably at some point in the 80's. EEven then it was probably quite comon till the Home improvment boom of thee 90's when a lot of older houses were rewired and/or had their fuseboxes replaced with circuit breakers
You can't draw 15 amps through a breaker or a fuse rated at 15 amps. Also there is a current surge when power is applied to equipment. Fuses are always rated higher than what the equipment uses or they would keep blowing.
Actually, you can draw MORE than 15A, for a short time, until the breaker gets hot enough to trip. This feature is actually exploited by things like refrigerators, which have high starting surge currents. Going over the rated current for a brief time is not a fire hazard because the wires don't have enough time to get hot.
You also have what is termed as slow blow fuse designed for high surge they will blow at the rated amps but after a set amount of Time
brief time
David Barts time delay fuse.
John D II actually a good bit of time an hour or more for a 15 amp. It'll hold a lot longer than a few minutes, that's why continuous (3hr or more) load is 80% of rated capacity. There's all different types of fuses with tons of different blow curves.
12 amps is what the wire feeding the device is rated at. 16 gauge wire =12amp 14 gauge wire=15 12 gauge wire=20
13 gauge wire used on 32 breakers in UK. 2.5mm^2
Hi Jason,
I've noticed that the US (and probably Canada) quote 110v domestic supply with a 220v option and they go on to claim a 440v three-phase system. How can this be? OK, it's easy to double voltage from 110 to 220 but that doesn't explain the spurious claim of 440v three-phase. Is someone seriously missing out on RMS (Root Mean Squared)maths?
In the UK, running 240v mains, this would equate to 480 volts three-phase, which is complete nonsense and we both know that this is seriously wrong.
The phases are set out at 120 degrees to each other and the voltage between phases works out as:
RMS V = the square root of 240 (squared) x 240 (squared) + 240 (squared), so:
RMS V = 240 x cube root of 3
RMS V = 240 x 1.7321
RMS V = 415 V RMS (between phases), and 415 V is specified in the UK as 415 V.
By the same token, the RMS three-phase voltage in the USA and Canada must only be 381 V.
Quod Erat Demonstrandum.
I can't speak to RMS versus measured. Typically, residential power is supplied as single-phase 115-120V/230-240V. Inside the "panel", there are two live busses, and the voltage to ground for each is 120V. Measured bus to bus, the voltage is more or less 240V. This is considered (and referred to as "single phase"). The two power busses are 180 degrees out of phase with each other, and each rated at 120V. Thus, the bus to bus voltage is 240V. There are home devices (like cooking stoves) which take advantage of the 240V supply, but most consumer devices (TV, computer, lamp) use 120V.
For commercial installations (with potentially larger equipment needs), the panels have three live busses instead of two. In this case, the voltages are more complicated depending on how they are generated (delta or wye). I won't go into commercial voltages, except to say that 120V is supplied to commercial installations along with the higher voltages through the same distribution system.
(I used to be an electrician in Los Angeles some years ago.)
I have a British plug in Mauritius and european
In America we call it a fuse box or circuit breaker box and I think the circuit you describe is called series for the UK and America uses parallel circuits. At least you have a drawing like a series circuit and that doesn't make any sense because voltage is not constant in a series. From the way you have a drawn I can't figure out what it means LOL. I have a degree in electronics and the comment that you have pinned doesn't make a whole lot of sense at all, much less the fact that the person can't spell. I guess I'm going to have to Google it and see what the heck you're doing over in the UK LOL. Okay, I finally found a circuit diagram on Google a ring is definitely the wrong word for it! The word implies a series circuit and that's not what it is. I don't know why they draw it going back into the fuse box? Electrically speaking, it's not a ring at all! It is however, the most contrary and bass ackwards thing I've ever seen. One thing to note for the so-called electricians here LOL give me a break. ( at least the ones I've read so far, I'm sure there are some real ones here) Watts divided by volts equals amps so at 240 volts you're only going to draw half the amperage for a 120 watt light bulb as you would in the US. This allows you to use a thinner wire in the UK. What you call radial or ring are both circuits that are series parallel. It's just that in the UK it seems to be one big series parallel and in the US we have different circuits for each part of the house and major appliances. something goes wrong in one room and only the outlets and lights for that room are going to blow a breaker. In the UK it blows the whole darn house LOL
Thanks for the “wank-stricity” lesson!
I'm not a pro, but I know how to wire up the outlet socket and plug, but anything more complicated like the mains ring, I will get a pro
It's not really more complicated. It's just that in America, we might have two circuits for the living room Outlets and one circuit for the dining room. It looks like in the UK they put the whole Darn House on one circuit LOL! They shouldn't draw it going back into the circuit breaker box like a ring because he electrically, it's the same thing; At least from the diagrams that I found on Google.
WIFIGHOST CRUISER Sorry but you're wrong. It IS a full ring. If you need to check it out properly you should search for UK consumer unit images and research the ring main more thoroughly. Inside the consumer unit EACH 32A ring main circuit has 6 wires: 2 brown (line), 2 blue (neutral), 2 bare copper earth wires that SHOULD be covered with green/yellow sleeving. Each neutral and earth wire is connected to the respective earth and neutral blocks and the PAIR of line wires are connected to the 32A breaker outlet. For any individual socket there are TWO parallel cable paths which means that the ring CABLE capacity is 52A @ 230v (typically, and definitely in ALL the houses I have seen is actually 250v) that's a total power capacity of 12.5 kW PER ring. We usually have at least two rings (upstairs and downstairs) and depending on the size and/layout of the house may have one or even several more. Power diversity comes into play also. Some of that can be effected by manual config at the consumer unit (fuse box) by for example, having a separate ring main for the kitchen/utility room. But that enables us to have a 3kW electric kettle, a four slice toaster, a microwave, a dishwasher, a fridge, a tumble drier, and a washing machine all connected to the ring main quite safely and without issue using a universal power plug (providing not all are switched on at the same time). If the ACTUAL working conditions are likely to exceed the 32A max load then a separate radial circuit or circuits can be provided or more likely these days, an extra ring main can be installed. The main reason a ring main is more efficient is that for the sake of a few EXTRA feet of cable over a radial 16A or 20A circuit (i.e. JUST returning the end of the radial back to the consumer unit, we can have as many sockets as we like on a ring main (under a certain square footage) and can plug in ANY moveable domestic electric appliance into ANY socket at ANY time. We can move that electric kettle anywhere in the house. Once a ring main has been PROPERLY and ACCURATELY installed and tested, the likelihood of a break in the ring occurring without some form of deliberate interference is miniscule. Current UK regs require that the installing is safety checked after ANY new installation work and checking a ring main for continuity (as compared to a multi socket radial) is simplicity itself and can be done from the consumer unit alone. Any faults are obvious albeit the location of the fault is slightly longer than a radial. Once a suspect fault is located and fixed however, it is MUCH quicker to verify correct operation than with a radial ... You just check at the consumer unit.
Extending a ring main in essence is also extremely simple using single socket spurs (not the best way but legal) single or multiple fused spurs (i.e using a fused wall plate to protect the cabling from excess load) or by breaking into the ring and connecting a new socket with additional cabling.
One other thing, unlike the US and Canada, the UK does not use (to my knowledge) aluminium cored wire in domestic environments and certainly not under 16mm^2 that I have ever come across in 45 years as a graduate electrical and electronic engineer.
THERES TO MANY BRITISH PLUGS OVER HERE ' CAN YOU MAKE A VIDEO ABOUT ENGLISH PLUGS AS THEY ARE THE ONLY ONES MOST OF US WANT IN OUR HOMES .