Surge Protection Devices - Part 1
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- Опубликовано: 31 май 2024
- A series on surge protection. In part 1, what are surges, where do they come from, and what kind of damage can occur to unprotected installations.
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I'm glad youtube recommended your channel. I get to learn something new each time I watch your videos. You are very well prepared and methodical in your explanations. Great Effort JW
I wish you’d been one of my teachers at school. Clear, engaging, and clearly invested in your subject. Superb.
Another clear explanation showing what these things are, and why they now an important addition, thanks John
After some time watching various sparky channels on RUclips I will honestly say that your channel is most informative or/and pleasant to listen. Thank you.
Negative comments I may write in private some time later on.
Thanks John, this is a great video, really helpful to explain the use of and requirement for surge protection. Very few people really realise the true extent & cost of damage caused by over voltage issues, one reason for that is that the UK insurance industry is very tight lipped about these things. In Germany this is not the case the insurance industry makes information freely available and they suggest that from all claims of "electrical or electronic damage" over voltage / surge issues are responsible for 31% of the claims. That is a huge figure, for anyone reading this and thinking "he's an idiot, I've never seen anything like that level of damage" ....well how do you know? Over voltage damage is not always immediate and spectacular, there may not be a huge bang and plumes of black smoke. You can have several incidents over a few weeks and it would lead to wear and tear, then one day flick a switch on and the equipment doesn't work. Do you immediately think "oh that must be wear and tear fro over voltage events" of course you don't. You think "oh that's broken, more money to replace it /repair it". SPD's offer longer life spans for equipment, increased levels of availability, reduction in down time and less maintenance. They are like "electrical life assurance for equipment".
Loving the big Clive style bridge rectifier symbol :) great video as always
Hi John, . You explain things so interestingly and understandable for the non exspert, plus I love it when you go the hole way and let us see things burn out and set on fire..
Keep em coming John...
Regards Antony
Warrington Cheshire.
Thanks John, a very nice introduction to purpose and limitations of SPD's in general.
Aside transients caused by atmospheric (lightning) you highlight the need for awareness of 'Surge Creating' equipment along with 'Surge Sensitive'.
great stuff. transient change of pitch of the voice always cracks me up
I've known of two instances where lightning strikes have had a noticable effect. Back in the 90's I was watching the TV in a thunderstorm - suddenly all the lights "strobed" once and the tv went to standby. No damage, just had to turn the tv back on. The second, much more recent incident was during a particularly powerful thunderstorm - a friend of mine's Router and computer motherboard got fried (I diagnosed the computer and figured out it was just the motherboard that bought it). I think this is a good example of what John is talking about here.
I knew a bloke called surge, he was French. I don’t believe protection was necessary as he was a great chap!
Your videos are excellent, possibly the best on here.
🕺🏽🍻
Excellent video John as always very informative, fitted a couple of SPD’s on last few jobs now
Two years ago almost all the plugged in devices with circuit boards inside them all died in the same week, I always knew it was a surge but now I finally understand why. Thanks!
Thanks John will share with family and friends!
Thank you for the lesson John
Whenever I need info on any electrical subject i check on RUclips if John Ward has made an info video on it, you are the god on electrical knowledge 😉
Most damage caused by surge I witnessed, was in the one of substations in a factory last summer. Surge (or few of them) busted the SPDs, but also busted electronics of a main circuit breaker and power analyzer. Later on, there was significant voltage drop that caused overcurrent, which resulted in melted 2500A busbars, because 2000A breaker didnt trip.
Perhaps that was to do with undervoltage and current spikes but sounds to me like the equipment was underrated and ubsuitable for the fault level. Did you manage to get to the bottom of this?
Excellent content and presentation , Sir !
the best english electrician on youtube :D
He is the boffin within the trade
Waiting patiently for part 2.
Excellent videos thanks. I rewired a property following a direct lightning strike some years ago. It hit an extension part of the property and more or less demolished it. If there was anybody in at the time it could have been serious. 2.5 mm and 6mm cables had been vaporised in places. Seemed to use everything it could as a path to ground. Open reach or British telecom were there for a few days doing street works.
I can believe a direct lightning strike would be really really nasty in infrastructure terms... if the customer's cables suffered that much damage... then yes the local substation transformer pushing 240 measly volts ,... is not going to stop the lightning seeing a live wire as 'something at earth potential', And as for phone wiring, i bet the openreach guys had 2 pits? [one before the fault and one after].
You're doing an excellent job, thank you :)
You are the best JW
Great 👍video with relentless explanations
I live in a neighborhood with underground power, and also one that seems prone to lightning strikes. I've had a couple (that I know of) strike within a hundred yards of my house in the last few years and I've also lost two electronic devices due to them. I'm in the process of installing a whole house protection system, but I also wonder if adding additional grounding would help. The soil is heavily clay, so water doesn't go very deeply and the conductivity must be poor.. I'm wondering if I should add an additional grounding rod at the electrical service entrance and another to the outside air conditioning compressor at the far end of my house.
In a nutshell, what I am asking is if improving the grounding will add additional surge protection, including that from induction motors starting up.
My kitchen had a mixture of fluorescent and incandescent lighting. I replaced the incandescent lamps with LED types and noticed that the LEDs were failing almost immediately. Finally it dawned on me that the failures were always coincident with switching the lights on or off. The only reason for this I could think of was that the chokes in the fluorescent fittings were causing a surge at switch on/off which was enough to damage the LEDs. I replaced all the fluorescent fittings with LED types and problem solved.
Not particularly surprising I hear you say. However, two things are worthy of note. LEDs elsewhere in the house of exactly the same type/manufacturer were not being damaged although they were on the same lighting circuit. I can only assume that the extra wiring length to these other LEDs had sufficient capacitance to suppress the surges being generated by the fluorescent fittings. The other thing I was surprised by was that the LED manufacturers (a well known brand) had never heard of this kind of issue before and moreover did not seem to be very aware in general of how sensitive their products were to what I imagine are fairly minor surges in the great scheme of things (assuming my theory was correct!).
Has anyone else encountered similar issues?
very interesting, i agree that the chokes might be the problem for the surge
Colin Hursell - if the two different types of lighting were controlled from the same switch, I’m not surprised. Inductors can generate high voltage spikes of 500V upwards when the supply is switched off. If the LED lights are on the same circuit, guess where this energy goes...
@@Mark1024MAK Shouldn't it go through a diode on the same board as the choke? Why would it even make it back to the line? The diode should look like a short and thus the path of least resistance.
Roflcopter4b - for conventional fluorescent lights that use a choke (inductor), there are no diodes needed or used. And the bridge rectifier in a LED lamp will just channel any high voltage spike into the rest of the circuitry...
Now if the designers/manufacturers of the LED lamp included some over voltage protection components, the lamps are likely to survive a lot longer.
@@Mark1024MAK I see. Come to think of it, it wouldn't make sense to have a diode there anyway. I was mistakenly thinking about it as though the inductor were passing DC (as in a filter reactor or a relay for example). In such circuits adding a diode in reverse across the inductor is almost reflexive. Doing this would make no sense at all if the choke is passing AC for obvious reasons. My mistake.
Would it really be so hard for them to just put a little MOV in fluorescent lights?
Also the inductance of the transformer primary in anything with a linear PSU would stop any short duration pulse doing much of anything other than MAYBE breaking down the primary insulation (which would have resulted in a repairer just saying 'nah yer transformer's dud')
Amazing explanation!!!
very informative.. great content.. God bless you..
That was certainly good insomnia protection JW, just a quick correction, “high voltage transients” even those from direct strikes to overhead lines, don’t travel very far before they dissipate either by breaking down the air resistance and finding a path to earth, or the insulation between adjacent conductors and finding a path to neutral.
HV injections (where a cross arm breaks, or a car hits a pole and one of the hv lines falls onto the LV network below it), on the other hand can really do some damage, because the voltage is low enough to travel down the network without flashing over, and it will continue to flow until the protective device upstream operates (current X duration = let through energy), and that little 20Ka MOV arrester you have there will either be a god send if it is properly installed, or, what the fire brigade will later identify as “the seat of the fire”.
I’ve seen what happens when a 11kV line breaks and falls onto some low voltage equipment below. Not only did it destroy the low voltage equipment (a 110V to 20V transformer, an smaller 6V transformer), it also literally blew the associated wires (1.5mm squared) to pieces where they were routed around a 90 degree bend. Lightening on the other hand (but not a direct strike), just takes out the so called lightening protection fuses or the normal fuses as the metal oxide resistor(s), gas discharge tube(s), surge protection diodes or Zener diodes draw a large current. Yes the equipment often survives, put new fuses and new lightening protection components are needed.
Actually the standard talks about transients travelling up to 2km and I have personally witnessed lightning energy travelling for up to 11.5km so it actually depends on the source generating the surge, the wave shape (they differ) and the total level of energy.
Great videos John! Just had an interesting one, a mains sander plugged into and extension lead that also had two led work lights plugged into it , started and then stopped the sander after only a second, and then both led lights blew their internal drivers. Assume due to a switching surge from the sander ac motor?Would a type 1,2 or 3 surge protector saved them, considering they were all on the same extension lead?
Most electronic devices have at least a token amount of surge suppression fitted. At the mains input you will often see a small (normally blue) disc called a metal oxide varistor connected across the supply input. These short out large spikes and have microsecond response times.
Precisely! At 15:05 JW makes a very large error. He says that the first component in any modern device is a "microcontroller". In actual fact, the first component is a fuse, followed immediately by a MOV (Surge Protector). The MOV and Fuse are specifically there to clamp any Surges, and if the current is too high then to blow the fuse and disconnect the device.
In reality, there is almost ZERO need for "surge protectors", be that in a fusebox or in downstream power strip, etc.
John Coops - there is absolutely no protection in cheap badly designed imported electronic crap. In good quality well designed electronic equipment, there is indeed built-in surge protection. Plus surge protection plugs and extension leads are available.
@@Mark1024MAK - That is exactly my point! Nobody cares if cheap badly designed imported crap gets killed by a surge. Good quality well designed (compliant) equipment contains built in surge protection to protect ITSELF. Consider how many of your own high quality devices have been killed by surges! So (generally speaking) the so-called "surge protected" powerboards etc provide no extra protection for good quality compliant devices, which makes them pointless as I said. It's totally idiotic to spend hundreds of dollars on a special power board to "protect" a shitty non-compliant self-imported device that only cost a few bucks and will probably fail from other causes anyway.
John Coops - agreed 👏
But these MOV's are designed to offer the withstand capability required by BS7671, 6kv at the meter, down to 1.5kv for the most sensitive equipment. They are a last line of defence and are not supposed to be subjected to repeated transients. What if your over voltage event is in excess of this 1.5kv as they frequently are?
What about the meter? are they susceptable to transients. Also with the dire need for isolators on the supply, would it not be a neat solution to have the spds and isolator in the same box that could be fitted while the meter wasbeing changed?
Sir exelent explain thanq very much👌👏🙏
Hi John.
Can you give any further insight into why the regs says that if you have a 2nd sub board over 10mtrs away that you would need a 2nd SPD. If there is a type 2 at the origin (ie meter box) on a property with an underground supply and there is a mains board 15mtrs away would you need a 2nd SPD in the consumer unit as well? I assume that if the SPD has done its job at the origin there wouldn’t be any need for it at the consumer unit as well?
So does the protection inside multimeters and the derived cat ratings also have to do with these same surges?
One of my neighbors had a lightning strike come down his chimney (breaking some of the brickwork) and go straight into his television, which basically exploded. The surge protector strip that the TV was plugged into suffered no damage. One of those weird things lightning can do I guess.
The proper is to put rail surge protector centrally
🤨 Were was the tv positioned? In front of the fire place (LCD flat screen) - hit the tv though the opening of the fire, next to the fire place - poor chap got shocked 😱 seeing the bolt come out of the fire, arcing off the grate and hit the side of the tv, or on the chimney breast above the mantlepiece. What type of TV? CRT/LCD flat screen. Were the other things plugged into the surge protected extension lead sockets affected? Was the aerial on the chimney stack? If a stove had replaced the open fire - the initial bolt had hit the top of the flue, conducted down it and arced off the stove and hit the tv?
@@samuelfellows6923 surge protector is protecting power line surges not chimney direct strikes
I'm guessing the aerial was attached to the chimney?
Surge protectors like that can only attenuate surges that happen on the supply lines. If the source of the surge is from an external point, they will do nothing
which spd uc/mcov should we use in home appliances 275v or 385v spd for 220v home use?
Brilliant. !!!
Does a lightening strike on a cable damage the insulation ? Does an underground cable need to be replaced if insulation damaged. Would that be a dangerous situation?
Geez.. this dude is the real sh*t....how did I not discover you before evades me. Such invaluable information broken down to dummy level. Pretty much you can be classed as the information digestive system for the average budding to even intermediate electrician. Break everything down to bite sized chunks. stuff u don't get in the classroom. Simply amazing. Pun intended:). Keep up the stellar job you are doing sir (as in teacher). A credit to the youtube community..
i think we could not use it as a replacement for the snubber circuit, could do you make videos on the snubber circuits?
Indirect lightning is a real problem where i live out in the country - overhead lines for both electricity supply and telephone. First thing we do at the first sound of thunder in the distance is unplug the internet router and telephone from the incoming line, if we don't it often leads to a lengthy tech call to the BT fault center trying to explain to them that a lightning storm just blew up yet another one of their routers! Have lost several that way over the last 10 years i have lived here.
100SteveB why aren’t you using both whole house and individual device surge protection? After the first device was killed and you failed to install basic protection they should be holding you liable... this is why the cost of service keeps increasing, people aren’t using basic protection and the ISP has to replace an expensive electronic device in hundreds of homes every time there’s a storm.
@@mattgayda2840 All my equipment is protected from mains AC surges, and they have always worked well, never suffered any damage from electrical storms. The only things that have been damaged are the BT master socket - that's always failed when my router failed. The BT engineer that comes out told me that there is surge protection built into the master socket, but it's not always totally effective if the surge is big enough. I have asked if i should use a separate protector between the master socket and the router but they advised me strongly against doing that saying i could be held liable for any damage occurring in the future. The biggest problem for me was that i had about 8 miles of copper between me and the exchange, nearly all of it overhead. But, fingers crossed, since we've had fibre to the cabinet, i have not had an issue - i now only have a few hundred meters of copper left.
Great video JW, when can we expect part 2?
Probably next week. It's already done. Currently editing part 3.
Thanks GOD BLESS YOU
That was good..now I know to go round and unplug everything of value or have sockets in the OFF position. ;)
hi john , another great video. quick question. can you get surges in houses that are near the rail lines at all? .Also I noticed a shop near by me one time that was a barber shop underneath a railway bridge and every time the train would pass over their clippers would go completely ballistic and make terrible loud buzzing noises when using them. they would have to stop cutting hair with them until the train had passed. it sounds bizarre but that's what happened. Hope its not a stupid questions I have asked. many thanks.
Yes, definitely. Very high current, either from rails or overhead lines = large magnetic fields. Also possible faults where high current flows to places it wasn't intended to.
John Ward - only if they are electric trains!
Andy chara - Electronic equipment used on the railway where electric trains are used is built to tight specifications to prevent erroneous operation. The pick-up on electric trains is a wide-band radio-transmitter plus the return current flowing back through the rails can also transmit radio waves and magnetic fields. But most problems are due to the electrical network suffering from voltage dips and minor surges at the train intermittently draws current as the train pick-up does not always make good continuous contact...
Good, useful intro 👍
How do I connect two pole surge protector to a distribution board
Sorry if a silly question, but could you connect one of those to a tv aerial coaxial cable to protect against lightning strike?
Similar devices are available for coax cables, phone cables, Ethernet cables and many others. All cables entering the building need to be considered, as surges can enter on any of them.
Does the surge arrestor get installed before the main breaker in the consumer unit or further" down stream". Some books I've read in South Africa says : install between the live and earth terminal. Haha its too vague... Need to visually see it?
After the main breaker, connections to the SPD require an overcurrent device (fuse / breaker) and there should be a method of disconnection for maintenance/ replacement.
In Oz the high voltage is run above the 240 volt lines and if the pole goes over (car Acident) The two come in contact and there"s your surge.
Dear sir, installed two cameras with 12 v adaptor (SMPS) in two flats and electricity went off and on in the two flats at the same time(the same block) , and one device in one flat was malfunctioning , i mean how to check the voltage signal Quality is stable or not is it high than standard , what are the possibilities that could destroy the adaptor in one flat and the other not in the same building , also instead of opinion about the video could the signal that comes out of the APC Power bank could be deformed from scientific point of view
How does voltage go up if neutral disconnected ? Is this something we need to know.. Can u do a video on this.
Thanks for the great video! There's only one thing I'm not sure I fully understood. Regarding the switching off the directly connected motor (without VFD), if it's done by 1p switching and you let the motor freewheel until it stops without applying any force to it, shouldn't the generator effect be avoided? I'm not disputing the transient switching effect here! Just the freewheeling generator effect
Power is generated when freewheeling, it will only slow down with electrical load applied or even a full short
Thanks for this post.please can you share to me cable and their suitable breakers.
Do you have a video on whether it is safe to install a 110v lighting fixture into a UK ceiling fixture? Thank you.
No, and doing that isn't safe - items designed for 110V cannot be used on a 230V supply.
Hi - can you please explain Lutron switches (dimmer switches) that control many zones (4-5). And also the wiring diagram of Lutron switches when arranged in two ways switches and an intermediate. I have not found it if you can can you please make a video or send me a website that can explain. Thanks
With a telephone line, the Linebox where the line from outside is terminated, there is a component in the Linebox to limit surges.
Excellent thanks. Can you explain how to connect SPD to home electric circuit and how to select.
@WhiteShadow2k1 better next video.....
@John Ward Should plugs(connected to an appliance) spark when connected to an unswitched socket outlet?
Yes, it's inevitable when connecting or disconnecting any load. All switches spark internally, you just can't see it most of the time. Same applies to connecting a plug, or disconnecting it.
The spark will be larger if the load is larger.
@@jwflame Thanks for the clarification. I always wondered if that was an issue with the appliance.
Hi John. Great video.
Have you covered any videos on hot water cylinder heating elements and testing? Mainly mims cable or equivalent, I
Would think NZ/UK cylinders are similar.
Kind regards
ruclips.net/video/obWkCGFhuus/видео.html
What annoys me about failures in boiler PCBs is that it's typically the failure of capacitors which can be identified and replaced for pennies.
Can any Line and Neutral connections be interchanged on a 4 pole SPD? Have to replace one which has N in left side but available one has N on left side. Would make wiring easier if I could use one L as Neutral connections and use the Neutral connections as L.
Sorry meant old has Neutral connections on Left side and new has Neutral connections on Right side.
If all 4 cartridges are identical then you can - however most are not, those used for N-E are different from those for L-E
MOV will dissipate energy via heat, so no need for earthing? How does Earthing differs from MOV SPDs?
Good Morning JW, Have you come across integrated Incoming isolator & Surge Protection devices such as Wylex’s REC2SPD?
It is designed to be fitted on the tails between the meter and consumer unit, hence protected by the service fuse.
Will be up to the energy providers I guess re. if they want to fit these instead of a basic REC2 isolator switch for existing installations (when a customer requests an isolator switch).
Would help achieve the short cable lengths required more easily in some domestic installations.
Would be interested in your thoughts.
Thanks Adam
Yes, one is shown briefly in this video: ruclips.net/video/f6PpvrCgyEA/видео.html
Unlikely that energy providers will be installing them as they are £90-£100 more than a standard isolator, however they are a decent solution if an isolator is required, as the cable lengths to the SPD are pretty much zero .
John Ward thanks JW appreciate your response 👍
Great explanation. I cannot understand why SPD's are being disregarded so much for domestic jobs even by the NICEIC, my local supplier says I'm the only contractor fitting them. Why are they so expensive I've just ordered some MOV's from a supplier at 10p each to experiment with. Looking forward to the next installment.
Like many things, it's the attitude of 'the old ways are best' and 'we didn't need these before' - both of which ignore the fact that electrical installations and the equipment in them has changed massively.
@@ruben_balea Looks like I need to delve into the specifications a bit more thanks for you reply. Can you advise why MOV's are used on live to earth and gas discharge tubes are used on neutral to earth.
@@ruben_balea understand a bit more now thanks very much.
Rubén Balea - I’m sorry, but they are still overpriced for what they are. Especially considering that any well designed good quality electronic product should already have some over voltage / surge protection built-in.
And lots of smaller local protection is often considered to be better than one central protection system.
Hi John,
Ze, IR etc testing should be on the main switch or on SPD?
THANKS
SPDs must be removed for insulation resistance tests.
They won't affect other tests.
@@jwflame thanks John
John Static caravans are now being supplied with type 2 SPD's in the consumer unit. The SPD is fitted up stream of the 30mS RCD in the consumer unit, however, the spd is downstream of the 30mA RCD in the external supply pillar.
What is the potential for nusiance tripping of a rcd caused by transient voltages being shunted by an RCD ?
Typos a plenty, that clearly should have read...
What is the potential for nuisance tripping of a RCD caused by transient voltages being shunted by a SPD ?
Basically none - typical transients and the response time of SPDs is in the order of microseconds, RCDs trip in milliseconds so transients are ~1000x faster.
However as MOV type SPDs get old, they do leak some current so there is a possibility of old ones tripping RCDs.
Those with gas discharge tubes instead of MOVs between E and other connections are used with RCDs to prevent that.
@@jwflame Thank you for the reply.
How does this sit with reg 543.4.7 when you have a 30mA RCD on the supply side of the SPD?
This is a bit off-topic, but I live in a fairly rural area in the US. Until a couple of decades ago, it was common for houses and barns around here to have lightning rods installed but I haven't seen one in years. Why did lightning rods go out-of-fashion? Are they not needed anymore?
In my country, often the metal sheath of the roof is connected to the grund, so the whole roof is grounded and u dont have to put any rods, unless the area of roof exceeds some numbers
Lightning hasn't changed so if lightning rods were needed in the past then they are still needed now. Maybe they used to be installed on the basis they they might be useful but now no longer because of cost and have been found not to be statistically useful.
Certainly if I was in an area where my house was the tallest thing around then I'd install a lightning protection system to a dedicated earth rod. I'd probably also look to adding some heavyweight transient protection at my incoming power point because in rural area it is probably coming from overhead cables
my job is designing mains fuse boxes for local installers and i can testify that almost 80% of them have some kind of surge protection.
also in my country i believe it is mandatory for government buildings to have a spd system.
a single type 1 and many type 2's is the norm but if see a upward trend of type 1+2.
also a new (ich) source of surges are PV transformers (solar panel) and car chargers.
they store a huge amount of power and use computers and electronics to turn it on and of very fast.
but if the software fails it can dump all of it by exedent.
it wont hit the 5000V but anything up to a 1000V is to be expected.
it will be way more local but they ar cropping up every ware.
if seen a carpark that had 20 charging poles and one car owner used the wrong card to check out and it cause a emergency power down because of some software bug.
in a instance almost all of the led street lights turned of and did not turn on again.
it was a expensive bug that did not damage the charging infrastructure so it was only a problem in the real world.
interesting, I hadn't considered the internal sources of potential surges...but that makes sense.
It's kind of like the use of a surge protector in UK phone sockets. (in standard line sockets its a 350v gas discharge tube across the line wires).
It was claimed initially to be lightning protection.... ultimately all it was there for was to prevent some idiot destroying a £400* ish line card by chucking his beer over the answering machine
*figure chosen from my ass, but 'expensive'
SoY_FooD Sir, what country are all of these?
the Netherlands for 95% and some for Germany and begum.
thx for the info
TheChipmunk2008 - old style British Telecommunications telephones did not have any semiconductors (apart from normal diodes) and the line equipment was electromechanical. Now if course both the telephone and the equipment line card are electronic. So the gas discharge tube in the line termination unit/socket does provide a limited amount of protection. Similar protection components are used in the exchange. However apparently cost cutting means that these components are not always fitted in new LTU units. Why should the telephone company care about your equipment (in the past you rented the telephone from them).
Why A.C. 230 Peak voltage +325V does not affect SPD? It's because the peak time is very short?
Thanks
SPD voltage ratings (Uc) are for AC voltages, not DC or peak.
We normally use a double pole switch or isolator for Motor right?
Yes for a single phase motor. 3 pole isolator for a 3 phase motor.
i have to three lightening strike jobs spreed over many years number 1 tv destroyed number 2 consumer unit blown from wall supply cable to house destroyed number 3 2weeks ago indirect strike lighting transformer and dimmer blown , so on number 3 an spd would i think have saved the day,all jobs in 0.5 ng flash density area page 102 18th edition. thanks for video john.
Very informative thanks. I worked for 30 years maintaining and installing ,fire alarms , door entry devices, CCTV and public address including 100 volt line on large and small installations. We hardly ever had problems that you have referred to with equipment being destroyed. It was built to withstand such things and worked for years with out problem. So I would question why these things are being fitted, could it be another way of frightening the customer into thinking "that they have got to have these fitted"!!!! Or are these transients and surges a new thing I think not.
Transients are not new, but the amount of electronics connected in a typical installation is far more now than in the past. Older equipment typically had a transformer as the first part of the power supply which is unlikely to be damaged, virtually all new devices have switching supplies which have electronic components at mains voltage, far more likely to be damaged.
Thanks for your reply, I did not want to criticise your consise video but point out that why do we suddenly need these devices and would new equipment be as reliable as the thing's it is replacing. I only retired last year and was still involved with this equipment. I have found that it us mostly still constructed using the time tested and reliable components that always been used.
Martin Winfield - my personal opinion is, “marketing” so that the customer can be charged more. Any good quality well designed product will already have suitable surge protection built-in. Some 1980’s computers that used switch mode power supply units have such protection as standard. And as John says, it’s not new. Industrial systems have had such protection since the 1970s onwards.
An reasonable quality electronic product will have inbuilt surge protection. In fact it's part of the electrical safety compliance testing (of electronics) in all countries. So generally, these SPDs are basically just marketing wank.
The only things damaged for the most part from any kind of surges I've seen so far are very cheap LED lights
Why is it that new build houses have fused spurs for kitchen appliances like fridge, washer and dishwasher instead of a unswitched single gang socket with isolator switch elsewhere? Something to do with regs?
Fashion, or people doing things a particular way because they always have.
No requirement for them now and never was.
At least in my (family’s home) case, Designer Kitchens’s sparky got it right - kitchen was replaced 5 years ago, 2x switched spur fuse’s above washer/dryer, dishwasher to single gang switched sockets. cooker hood, built-in microwave, oven, tower fridge/freezer are plugged into single gang switched sockets. Induction hob connected to 30amp red dip switch.
@@samuelfellows6923 thats good. I like the sockets over having to wite the appliance into a spur as some may not know how to do it. Also easier for maintenance or replacement
I usually have an isolator above the worktop controlling a flex outlet plate with a trailing single socket. Sometimes the appliance won't sit fully back if the plug is behind but a short trailing socket can be repositioned where there's room and the appliance still keeps its original plug.
Ben's pets - there is no requirement for a switch on any 13A socket. If the socket is in a hard to get to location (behind an appliance for example), it’s good practice to supply this socket from a switched fused connection unit that is placed where a user can get to it and where it is obvious what it is for.
Let's see you create a surge to test the S.P.
TVs made pre 1970 used Electronic switched mode power supplies, the number one cause of failure were clumsy customers watering their plants on top of the TV, number two was capacitors drying up as they used to get so hot or the CRT died after 7 or 8 years of use. Surges were not a problem then even though the electronic components were inferior to those available today.
Any mains powered equipment that is supposedly CE marked should include its own surge protection device, the reality is the addition of this 15p component (MOV) is usually left out to save cost by unscrupulous manufacturers.
I have seen MOVs fail spectacularly, I would not recommend using these in a plastic enclosure!
Telephone lines are a special problem. One side of the telephone pair is connected to earth at the exchange (which side changes briefly prior to your phone ringing, to warn CLI there's a call coming). A lightning strike near you, or near the exchange can put a big transient between exchange earth and your mains earth. If you have an ADSL modem (aka ADSL router, aka hub), that transient is likely to kill it (the same applies to old dial-up modems). Yes, the modem's power supply will be isolated, but if the transient is large enough there will be some leakage current through the class Y noise-suppression capacitor (or even breakdown of transformer insulation or even tracking of damned big sparks across the PCB). A direct hit on the phone line or power line puts an even bigger transient on there. If you have a wired connection from the modem to your computer, that just gives a more direct path for the transient to take effect, and may result in death of your computer as well as the modem. Modems/ADSL modems are not designed to cope with large voltages between mains earth and phone earth. Depends on the technology inside, but 10V can be enough to fry a chip.
Bottom line unplug the modem from the telephone line if there's a storm. Unplugging the modem from the mains instead isn't as good, since the mains plug is going to be touching or near objects at earth potential, and even insulators have enough capacitance for there to be leakage current to transients. Unplugging from both phone and mains is better, but if you're only going to unplug at one end then unplug from the phone line.
I've had three modems killed by unanticipated nearby lightning strikes. Two times, the first I knew of the storm was with the nearby lightning strike that killed the modem. One time I was out of the house on a day when no thunder had been forecast but a storm brewed up anyway. One of the times I had a phone on top of my tower computer and there was a damned big spark from phone to computer case.
thats why older BT master sockets had a spark gap and a MOV across the pairs... but unfortunately these interfere with high frequencies, so they took them out
@@jaycee1980 The spark gap and MOV protect against a voltage transient across the lines. They *will* stop a transient damaging an approved phone (which have to be designed to cope with transients too small for the spark gap to stop).
They don't protect against a voltage transient between mains earth and telephone exchange earth. They can't, because mains earth is not part of the master socket. But even if it were, a spark gap couldn't protect something that can be damaged by 10V transient. Not sure an MOV would be up to handling transients that small.
Brilliant. Thank you.
Nice nice sir
Please can you explain how 240v is obtained as the average of a sine wave alternating between +340v and -340v? Common sense would suggest the average voltage would be 0v…
en.wikipedia.org/wiki/Root_mean_square
Hi John what is a different between T1 type SPD & T2 type SPD???... Many thanks. Keep well!..
Covered in future videos. This is part 1 in a whole series.
@@jwflame cheers look forward to it 👍
Sir what is different between over under voltage control device and spd pls help
SPDs deal with transients - high voltage spikes that last for nanoseconds / microseconds. Over voltage devices disconnect if the supply voltage exceeds a certain value, and will disconnect in milliseconds - thousands of times slower than SPDs.
So what you are saying older electronic stuff was made from better stuff and just better made. Computer PSUs always had a filter plug for the inlet there now only on Hi end stuff. Old tech took a beating and it was still ticking.
hello teacher I am an electrician in Thailand. I would like to ask the teacher how many technologies SPD has. What technology is there? thank you teacher If I use the wrong words, I apologize because I'm not good at English. I use a translator app, teacher.
@20:20 "Shart devices??"
thanks where do i find part 2
ruclips.net/p/PLVsHvs2Suqmo0GS6oa9l2kCN-A7QhIQe8
surge protection is important but a t consumer level this is not important as surge protectors can protect the devices, but do not protect the device from FM interference that occurs during the fault... In the Power System transients will always clear over the wavelength distance since the transients occurs form a Line-to-Line fault
In reality, I've yet to measure a UK voltage lower than 240v RMS. I'm always mildly surprised when engineers refer to our '230v' supply! Maybe it's regulated more tightly in Europe, but every meter I ever used gives something along the lines of 243v - 248v. This is in the South-East, but isn't voltage universal across the UK grid? Not sure.
Frequency is the same everywhere in the UK, voltage depends on the local transformers and what loads are connected. 240+ is still common in most places.
@@jwflame Thanks for that, John.
@@Blitterbug If I remember everything right that comes from the harmonisation with most of mainland Europe. Here in my country 220V used to be the norm (old people often still call it that as well) and back in those days I'm pretty sure the norm was 240V over there in the UK. They settled on making 230V RMS with a tolerance of -6% and +10% as the new norm, so effectively 216.2V to 253V is within the specification tolerance.
I guess they went with that so that all participating countries could retain current infrastructure while gradually moving over to the new mains voltage. In my house I can remember usually observing between 230-235V.
Extra stuff - 90% plus of equipment does not care if the mains voltage is slightly low or slightly high, so it does matter...
@@Mark1024MAK I'm aware of that. It was really just a response to the first comment in this thread to clarify that it's within the specification tolerance.
surely now in the 21st century all these sensitive equip has it all built in to say the door entry or fire alarm without it would be a no brainer
Why do sharpies on paper sound like nails on a chalkboard to me now?
1.21 JIGAWATTS!
About 10 years ago my home was affected during a thunder storm. The surge took out my TV, Alarm, Computer. Insurance Co. refused to pay out calling it an act of God. Next door neighbour also affected. I think SPD's are a good idea.
to which you say "Prove God exists. You cant ? Pay up then"
Norman Hartill - the trouble is, just like any other surge protection system, SPDs will only provide protection up to a certain point. Beyond that, they will be ineffective. And if they do absorb any significant power, they have to be replaced. So in your situation, it’s perfectly possible that they may not have helped.
Years ago my parents house was struck by lightning it went down the chimney and blew the aga right across the room and buried it in the wall opposite totally destroying the radio that sat on the sideboard along with the sideboard. I dont think a surge protector would have been any use at all in this case. And when my father got home he was berated by the neighbor who was very angry that our chimney pot was now lodged in his roof.
On it's own, surge protection would not have helped there. However a lightning protection system with SPDs would have.
@@jwflame or just a lightning rod with heavy path to earth I guess... but what are the odds of that on a normal domestic dwelling?
Equiluxe1, your Dad needed a CPD (Chimney Pot Deflector), not an SPD, but seriously, no SPD on earth will help in the event of a direct building strike, only a lightning rod and buried earth mat could have helped there (have a close look at the spire of your local church, you will be able to see the heavy copper straps heading up to a pointed rod at the highest part), the lightning has to be given a suitable low resistance path to earth or the water soaked chimney pot and brickwork will take the hit, I hope everyone was alright and that your Dad his chimney pot back.
@@elonmask50 Don't think many houses had lightning rods in the 1950's not many houses do today either. I have seen places where there was a lightning rod and they are are still damaged from a strike, not here in the UK but in Africa and the US. Well designed equipment will have its own protection built in but all these protection devices are based around MOV's and they wear out over time without any major spikes, so I am not convinced that permanent surge protectors will be anything but trouble a few years after fitting. I have seen MOV's explode causing a lot of damage in doing so on equipment that was not connected to mains and never was and not struck by lightning just broke down and went dead short in heavy current system.
Equiluxe1, you are making my argument for me, that’s exactly my point.
So, modern devices don't have magnetic transformers, to save money, and they don't have surge protectors built in either, to save money. My television recently went bang, and the Freeview box won't work either. But they don't put anything worth watching on TV anyway, presumably to save money too.
Old saying among electrical engineers: Man makes surge/lighting protectors and God laughs.
ruclips.net/video/DWBFHjE5zK0/видео.html Concerning Indirect strikes:
Could one compare it to moisture gathering up on the power-line, and further on into droplets, that eventually drips of the power-line, resulting in the surge travelling along the line?
The example is just in a figuratively meaning.
How much does it costs to get a smart meter peter mc donald
They are provided by your energy supplier, there is no individual cost to having one installed.
Ultimately the cost of them is included in electricity bills, just as older types of meters were.
Very over priced items, for all they are. Im guessing a lightning strike would also damage rcbo,s too