Radial Circuits
HTML-код
- Опубликовано: 16 июн 2016
- Radial circuits for socket outlets, cookers, shower and many other items.
Ring circuits: • UK Ring Circuits (prev...
Lighting: • Lighting Circuits Part 1
Patreon: / jwflame
Contact info, sending stuff in etc.: xo4.uk/?YTT 
Наука
I'm brand new to the field after a career change, currently studying in college, but these videos have been exceptionally helpful and informative. A basic drawing illustrating these circuits have given me a crystal clear understanding of the basics.....so thank you, your videos are much appreciated.
just started an electrical course, they have given me a text book to learn. That was all they gave me. Very hard to study from just a text book. Your videos simpleminded everything and made everything seem easy. Good video, Easy explanation.
When talking about lighting circuits at the end "Having switches so you can turn them on and off always a handy feature to have!" John I don't think you realise how good your one liners are. Great videos learnt so much from them.
I'm changing careers and I'm doing a crash course in electrical installation at one of these private 4 week collages.
Your explanation is far superior to that of my tutor 😅
Thanks for your video
Popping over here from a link on Ring Circuits. American with electrical background curious about how UK wiring works. Now I know what a Consumer Unit is: Fuse Box or load center as we call them. And where we have black/white/green UK uses brown/blue/green for hot/neutral/ground(earth) in the same way.
Thanks, John Ward, as you are making things very clear in these vids and I understand way more than I ever got from previous Google and RUclips.
Love your videos John, very clearly explained without all the jargon. Superb mate.
Thanks for explaining those circuits. Following from Sydney Australia
Wow thanks John, a man who can ,explain in such a way that the beginners,are able to digest and understand 👏 👍 you have a new fan, cheers mate, .kenny
Excellent series,very informative and well presented!
This is the info I have been searching for. Very helpful. Thanks a lot
Very clear and concise video’s John, making it so easy to understand. Thanks very much for sharing
very informative video ,thanks for taking the time to share your knowledge, I find the way you explain electrics make it so easy to understand.
Thanks, my interest is being cultivated by your videos
John your the best, I am on an intense electric course and they don't have time to 1 to 1 teach me what's going on, after whatching this video and the one about ring circuits I get it, your so clear to understand and u don't use stupid cleaver language and your pictures are Fab :) thank you so so much
Brilliantly explained videos in a calm clear manner
JW you are a legend ! Brilliant stuff
great video, thanks for making things so clear
Great video, simple explanation. Well done
SIMPLICITY PERSONIFIED. Just as a lady DIYer watching these videos, I can now fit my own extractor fans with timer and add additional sockets. I have learnt so much in such a short time and have saved loads of money but esp time and stress from begging electricians to come and do a very small job like those above. They want big jobs to compensate for just coming out - I don't blame them and now I won't be calling or waiting endlessly / finally blaming them for forsaking me. HOORAY!!
Joe adam i love it when you girls get into electrical jobs you have proved that it isn't as complicated as it seems wish my wife would do job's like this (oh and yes I'm a sparky) I do cook and wash the dishes to 🙄😳
So useful man your help is really helping me at college
I have learnt so much watching your videos, thank you!
That's a really helpful video. Thanks so much. I have learn allot. I knew it would be pretty simple and your instruction makes it so
Many thanks cleared alot of confusion up alway got mixed up with Ring and Radial circuits cheers
Thanks for the videos I am learning a lot from them. I am going to wire up my garage in the future.
Just did mine
"Created by lucifer himself" had me chuckling for a while! Thanks for another great upload JW!
Are you saying you *wouldn't* sell your soul to satan to save a minor amount of copper wiring?
Kirchhoff the devil
Only in lighting circuits. Lucifer was the "angel of light" before his fall. ;->
I lol to at that
true @@parko1965
Thanks John great informative videos
At last …someone who who can teach electric engineering Clearly ,thank you!!!!
Good videos. I'm learning a lot.... in a stress free way.
Excellent video JW
Thanks for you videos watched in the past. Excellent the way you explain. Real tutor.
Have you got any video regarding installing a grid control switches in the kitchen. Much appreciated
Thanks John. Very concise videos.
Thank you John.
Thanks JW.
Hi John, very concise explanation. Isn't this adding a spur off a spur....I thought it's not allowed.
There is no concept of spurs on a radial circuit, because the cable is rated appropriately for the circuit breaker or other protective device, such as 26A cable with a 20A circuit breaker.
Spurs only exist on ring circuits because a single cable could be overloaded, as the cable used is rated less than 32A, but the circuit is protected with a 32A device.
Hi JW..just ofund your great channel...and I agree with Robin Jones..your "Lucifer" comment gave me a good laugh
Love your videos John Ward! 1st yr apprentice Australia
I wished videos like this were available back when I was an apprentice. Best wishes for your Electrical career.
Your explanation of the current flow in the CU (around 10:20 onwards) I found especially handy, thank you. The rest of the video was great too. Seeing a bunch of things connected with wires can be confusing until one pictures the current flow.
What you said about flicking the switch on a breaker isolating the line only (and not the neutral) was interesting. If you wanted to isolate a circuit (and just that circuit) properly, would you also disconnect the neutral from neutral bar, or remove the MCB/RCBO from the CU completely? I'm asking for a friend (!) who is remodelling his en-suite.
Nice explanation, thank you.
Hi John, Great videos, helped me loads over time. Any advice/videos on wiring a 32Amp 4 Pole Rotary Isolator switch which I have to install, single phase 230v. It's for a compressor which takes a high surge at start up.
Excellent as usual yes the lucifer pun was brilliant thanks jw
Really helpful video m8,cheers.
Thank you JW
Excellent! Many thanks.
Can we have have loop-in and junction box lighting circuits soon please John, along with your thoughts on these? Thanks!
Already underway, will be available in a few days.
Thanks John! Always enjoy your videos by the way.
It's still a 2.5mm cable as used for a ring main. The MCB in the consumer unit limits the current below its rated value of 26A
John Mathias, that is an important point to make
Your brilliant mate thank you
Clear no nonsense information !
Wonderful man.. Thanks heaps
When we get the video on the ring circuits could there be a section on extending them, rather than adding a fused spur?
The people who dislike ring circuits often talk about the possible wiring overloading if a line or a neutral wire or connection becomes loose and no longer makes contact/good contact or is removed.
In a radial circuit (as in many other systems) if there is a loose connection (say because a thermal screw was not fully tightened) all the downstream socket outlets may work for months or years after the installation was installed. But at some point, the increasing contact resistance of the loose connection will cause overheating of the terminal of the socket outlet if a heavy load is used downstream of the loose terminal. Which potentially could result in a fire.
What you say for the radial circuit is also true for a ring circuit that has broke into 2 radial circuits. All you have done is stack failure modes and ensured that the circuit is underspec, and will continue operating as though all is normal.
Alot thanks Mister
When a radial circuit goes outlet to outlet, the final outlet is often located in a nearby location to the first. I had thought about if it is a good idea to add the connection between the first and final circuit to complete a loop. This way you can prevent arcing if a wire breaks in a similar way to ring mains. Or perhaps create extra redundancy in the system. There is nothing in BS7671 about it though. Would it cause an installation test result failure?
Nice Visio . Could u please wright t the steps for each test
Like removing light , switches off or on in all type of each test to be carried .
Thanks again .
Thank you John
I'm just wondering if you could do a video on campervan installation, of both 220 volts and DC voltage
My son is fixing his van
And I'm a bit confused myself how to do it from an inverter charger .
This machine is producing AC and DC
If you didn't do 1 already
Many thanks
This is great. Can't see why you'd ever have a ring main at all nowadays, even if you're changing one our as long as you either use 4mm for the 30 amp MCB on the existing ring you're removing or swap to a 20amp MCB if you're sticking with 2.5mm.
Hi John only watched a couple of vids but would like to ask if you have covered initial verification such as checking main bonding before starting any electrical works, 30mA RCD protection and correct operation, of any RCD'S ie disconnection times with a compliant and calibrated meter >300mS and >40mS etc. Obviously you would also be advising on installation methods, maximum earth loop values for the protective device/fuse and breaking capacity to ensure circuit/installation complies with tables in BS7671 and guess you also advise how to complete the correct certification as required as detailed now in BS7671 2018 as from 1st Jan 2019 including AFDD arc fault detection devices....
JW
Do you have to earth bond between the metal back box and the socket earth terminal on a 13A radial or ring circuit given that they are wired in T&E 2.5mm cable, in order to be compliant with BS 7671.
I was led to believe that sockets wired this way did not need to be bonded to the back box as they will be bonded through the fixing screws.
And only if wired in conduit they would require to be equipotentially bonded. ?
Can't seem to identify in Regs !
I'm watching from Florida. I'm surprised at the wiring of the disconnect switch for a hi power single load circuit. In the US we run the wires as you've shown but only the power wire is connected to the switch, though a screw was added to the mounting yokes for earthing in case, say the mounting box is plastic and someone's finger contacted the screw that holds the cover plate to the yoke. Is your switch multipole and are the neutral and earth also switched? Or are there just terminals for earth and neutral? Are wire nuts used in England?
Thank you for all your great Videos JW.
Can you / anyone please let me know what the max length of the cable run (2.5mm) can be for a Radial?
Another question, if the cable is going through insulation, what size cable and mcb would be required?
Thanks for sharing 👍
I admire a man who slopes off to a quiet room to proudly display his organ on the Internet
Thank you sir.
great vid
Thanks John, thats the clear plain English answers I was looking for to assist me in my garden summer cabin project as far as 240v sockets go.
Does anyone have any helpful vid links to helping with our plan to have LED lighting and USB charger points running on a separate 12v system via a couple of hefty car batteries fed from solar panels or trickle charge from mains if needed.
Many Thanks
Unless you are determined to have the solar panels for some reasons other than cost, or you can get the parts for free or next to nothing, don't bother. The expense of the panels, batteries and charge controller will far exceed any tiny savings from not using 240V power for lights.
Julian Ilett has many videos on solar power: ruclips.net/user/julius256search?query=solar
Hi John, must of watched this video a dozen times. What connection method would you use in an existing installation and I'm breaking into an existing socket so there'll be 3 2.5mmsq at the one location. A deep backbox and take tails of 3 wago connectors for the line, neutral and cpc? Or do it like your video?
I thought you needed to put in a 13amp switched to protect the cable if you want spur and spur or is that just with ring circuit
In my country radial circuits are done a little differently: instead of looping in and out from sockets all the wires for the various sockets are linked together in junction boxes (one for each room or one for two/three rooms), and then a single wire goes to the consumer unit. In fact looping in and out of sockets is prohibited, the only exception are sockets on the same box in the wall, otherwise you should use a junction box. The reasoning is that this way the sockets is not a part of the circuit and doesn't carry a load. The problem comes when you have a damages socket, where the wires are not secured correctly, and that carries the load of all sockets in the circuit, with the potential to overheat and start a fire. Contact of sockets this way only carry the load of what is plugged in the socket itself. Also troubleshooting is much easier that way, since if there is a fault in a socket is easy to know which one is.
What country are you in?
Hi John. Me being "old school ring mains" I have to question the theory of using that poor old double socket getting used as essentially, a junction box. If those screws are poor, or not tight, it will get hot.
I have always had a rule of never putting more than two wires in the back of a socket, for that reason.
That said, a ring main (I know you don't like them for reasons of testing difficulties) lends itself to the convenience of load distribution.
I understand your concerns over overloading near the distribution board, but this is directly proportional to where the sockets are positioned on the ring, and providing the trip is of the correct rating to protect the cable, that is dealt with.
David (G1ZQC full licenced Radio Amateur)
PS we have been using Surge Protection Devices for the best part of a century.
It might be worth noting that some RCBO's also have an earth tag to connect to the earth bar in the consumer unit.
So is there any reason why star circuits are not used? By a star circuit, I mean a 32A MCB in the consumer unit. 4mm squared T&E cable to a distribution box. The distribution box contains three busbars (one each for line, neutral and earth) each with suitable size terminals, one for the incoming cable and say six other thermals for the outgoing cables (each terminal being intended for just one conductor wire). The socket outlets can be single or double and each is fed via it’s own 2.5mm squared T&E cable from the distribution box.
Really interesting and a great video. What is the purpose for using RCBOs instead of just a circuit breaker in the Line (Live)?
An RCBO provides protection for both overload and where there's a fault to earth. So, if a person accidentally comes into contact with live power, it only takes a few tens of milliamps to get a lethal shock. An RCBO (or and RCD/GFCI) should trip before the current reaches fatal levels. Also, it will trip on certain sorts of appliance faults. For example, if water in a washing machine or kettle leaked into the electrics, either of which might end up being dangerous even though they don't pass enough current to trip the overload.
thank you
Great videos, thanks John. One quick question. I am converting a small outhouse at the back of my house into a utility room. It will house a fridge freezer, dishwasher, washing machine and tumble dryer. I was planning to install a 2.5mm ring main protected by a 32A RCBO, but instead could I use a 4mm radial circuit still protected by a 32A RCBO? Also, could I spur off this radial circuit to supply a 5' LED tube and extractor fan both connected via their own 5A FCU and 1mm cable?
Yes, 4mm² 32A radial is fine. 5A FCU for lighting and extractor is also ok, the only minor disadvantage there is that a fault on the 32A circuit will result in no lighting.
Can't find any videos on the different ways you can wire an fcu ie as a spur or into the ring main. Any help welcome
I've just had the first fix done......... So, if the final leg of a ring back to the CU is disconnected and down rate the MCB to 20A (which is more than adequate for me), I'm left with a radial. If I read it right, the advantages would be more flexibility for expansion in terms of spurs off it (if needed) and a lot easier to test?
Great Video as always JW! quick question, How do you interpret the maximum floor area for Radial Circuits?
Decades ago it was defined as the floor area that the sockets supply, same as for ring circuits.
Floor area hasn't been a requirement for 40+ years. Real limits are the total load that's likely to be connected and the circuit length.
Great vid as always. Thanks a million. Question: Can we add a junction box between two sockets to branch out for more outlets?
Yes. If the junction box is to be concealed, it needs to be a maintenance free type.
@@jwflame Would this be notifiable under Part P?
Great thanks
In my garage I have a cable running from the CU into a 3-way junction box and then out to two double sockets. It was installed by the previous owner but I need to add another socket. Do I need the junction box?
Recently on a site with a more qualified spark telling me I can't just spur of a radial as youd overload the cable as it's a new circuit, so he pursued his ring and struggled to get 2 cables through a place one cable would walk through
I normally run 20amp bed rooms and sitting rooms then 32amp 4mm in the kitchen
Is this the quality of modern day colleges John?
He does voice overs for airline pilots with dodgy middle east accents his delivery of "this is your captain speaking" can't be matched
stevieboy1986 spurs with more than one outlet need to be fused "13A" because the load is no longer shared in a ring main. Remember the 2.5mm cable does not support 32A which is typically the protection on a ring main. On a radial circuit with 2.5mm, circuit is protected by a 20A MCB which is within the cables current rated capacity for method 3 clip direct so no need to protect it with a fuse.
Is the RCBO the same as a GFCI device in the US? Thanks for another great video.
RCD = GFCI, only trips when there is current leakage. RCBO = RCD + Overcurrent Protection Breaker (Think of this like a fuse)
@@OliverONeill wrong way round
@@johnbower nope
Thanks for these really great videos, although I'm still a little confused about one point. In your videos on ring circuits you mentioned that a ring was able then to carry 32amps so I understand having a 27amp breaker would be ok, although the problem is that if there was a break in the ring the cable would be taking more current than it's intended. So in this case how would a radial circuit be able to carry more current? For example, if I had 2.5mm2 cable in a radial circuit with a supply that carries 32amps would that be a problem?
The basic concept of a circuit is that the cable is rated higher than the circuit breaker, so the breaker will trip before the cable is damaged.
A ring is a special case as there are 2 cables, which is why cable rated less than 32A can be used with a 32A circuit breaker. Only valid if the ring is intact and there are 2 paths for the current to flow.
For everything else, the cable must be a higher rating, so for 2.5mm² cable the usual choice is 20A or in some cases 25A. If a 32A radial was required the cable would need to be at least 4mm².
@@jwflame Thank you, that's very helpful.
In France the regs say a radial of 2.5mm cable can supply up to a maximum of *eight* sockets. I have 12 sockets in my living room (two behind the wall hung TV and sound bar alone). In France I would need two radials, each with its own breaker at the CU, for the 12 sockets. Madness. I have one 32A ring circuit serving three rooms and a hall. In France that would be around four or five radial circuits, each with their own breaker at the CU. The CU would be bigger and more expensive as well. All needless expense and hassle, when one ring circuit would do it all.
Rings are not safe? Have an AFDD at the CU as recommended by the regs.
Thanks John - super video. Would you be happy using one radial 2.5mm cable for a kitchen running freezer, fridge, dishwasher, extractor fan, and 7 sockets? (cooker seperate feed of course!)
would probably be OK, best to either use a ring or a radial with 4mm cable both of which you can use a 32amp breaker
Are YOU hoping for a career in the RAF, perhaps as a technician or Officer? Good, then pay close attention to this man's bearing, tone, and dry humour. This will be expected of you during every crisis and in the Officer's Mess afterwards.
it's like having JW in my house as I got nice new 4k tv
But the video is only in 1920x1080p maximum, so your display will be stretching it 2x both horizontally and vertically to fit (3840x2160).
9ff70f96 I was waiting for a comment after I posted. My TV upscaled video. It's quite impressive viewed on 4k. Much better than 1080p on my old tv. Sony sure know how to fill in the blanks
HI John You make some great videos - well explained and understandable. I have been looking for certain info on RUclips but not found a video that supports this. This is if you move into a new house there may be lots of sockets in the rooms. These may all be fed by one feed from the consumer unit in an older house or may have separate ring mains - one for upstairs - one for downstairs and maybe one for the kitchen, in newer build properties. Here is what I would like to find out......What method would you use for tracking the run from the consumer unit to the first socket, and then the second, third and so on. So you could produce a realistic map of the ring main ? Without having to rip up floor boards and being totally confused with the myriad of wires you will find ! Is there a simple way to
do this ?
If you really wanted to do that, then disconnect the wires for the circuit at the consumer unit, temporarily connect L&E together in one of the cables at the consumer unit and then check resistance between L&E at every socket. Resistance will increase as you get further away from the L&E link and be greatest at the other end of the cable.
Same can be used for radials, the highest resistance will be furthest from the consumer unit.
@@jwflame Many thanks John.
Chris Ward - Note that in some properties, the ring circuits may not be one per floor. But instead each circuit may run via the ground floor ceiling/first floor void and run down to sockets on the ground floor and up to sockets on the first floor. For example if you have two circuits, they may be separated into two, one feeding the front rooms with the other feeding the back rooms, or East / West or North / South etc...
If you want a quick way of tracing live circuits, hire a CAT scanner. Power down and isolate (including neutrals) all circuits except the one you are investigating. Then plug in a suitable load (such as a heater) at the furthest point from the consumer unit on that ring circuit. Then by using the CAT scanner, you should be able to get an idea of where the cables run. Confirm by using the method outlined by John, as the CAT scanner method is not always accurate if multiple cables run in parallel. Alternatively, also fully isolate the circuit you are investigating (line and neutral) and separate the wires from each other at the consumer unit. Then connect a ‘tone generator’ between one wire (either line or either neutral) and the main earth in the consumer unit (NOT the circuit’s earth wire). Set the CAT scanner to the appropriate mode to detect the output from the tone generator. You should now be able to trace the cables. Again, if the cables from the same circuit run in parallel, it is not possible to determine which is which, so again, use John’s method to confirm.
I've never seen an RCBO with the neutral tail coming out the side. That would prevent installation in adjacent position on the DIN rail. The RCBOs that's I've seen have the neutral tail (and usually a functional earth) emerging from the underside.
Hi John... Would it be possible...like in a cooker circuit for example...to run a 6mm or 4mm radial circuit from a 20 or 25 amp mcb/rcbo in a radial circuit for sockets...in fact would you recommend that socket radial circuits are run in 4mm minimum...just to be certain of no cable overload?
Dividing a large hose into bedsits...and contemplating running individual 6mm or 10mm to each room for individual consumer units ....20 amp rcbo's for radial sockets and using 6 amp rcbo's for the lighting.
Radial circuits can be any rating you want.
A 20 or 25A circuit can be done in 2.5mm² cable, unless the cable is installed through insulation or is of excessive length.
No point in wasting money on oversized cables, the MCB will prevent any overload - the basic concept being the cable has a higher current rating than the MCB.
A CU with only a 20A and 6A circuit could also be supplied with 2.5mm cable. Perhaps 4mm in some circumstances.
Thank you...
Been enjoying a JW afternoon's education and nearly missed the Lucifer accreditation. Had to take time out for a laugh.
I just need to ask is this exactly the same as a tree radial,Someone has mentioned to me this phrase,or is this something completely different,great video and thanks again,
how is the trip switch valued.For instance in a kitchen where you use more appliences.Do you have to add up all the amps need.
Determine expected load for the circuit -> select appropriately sized cable for that load -> select suitable circuit breaker to protect the cable from overload.
Circuit design. Tables tell us the maximum current cable rating depending on installation. If a cable is open and clipped to the wall the current rating is high, while a cable embedded in plaster is much lower. In a circuit this is generally mixed as it works its way through the fabric of a house. What do you guys do? Take the lowest derated figure of a circuit? If most of the cable of a 2.5mm circuit could take 27 amps max, but a short one foot section is derated to 18 amps, is the lowest figure taken as the maximum current allowed in the radial circuit, 18 amps. That would mean an MCB of 16 amps on a 2.5mm cable. What do most do?
Hi John, if you were wiring a new kitchen would you choose 2 radial circuits over a ring main? Assuming that the cooker is on its own circuit also. Thanks.
While John has not yet answered you, his remarks at 0:30 and 12:50 in this video and his comments in ruclips.net/video/hZN6hiGLtrE/видео.html should give you a fair indication !
What size wires are used for radial as opposed to 2.5mm used for ring circuits?
Any size you want, provided the circuit breaker (MCB) or fuse is an appropriate size for the cable.
Common options are 2.5mm² cable with a 20A MCB, 4mm² with a 32A MCB, or 6mm² with a 40A MCB.
I have a 300/500V cable coming out of my consumer unit running to a single double socket, 2.5mm possibly. Is this ok to extend into a radial circuit for washing machine, and general utility plugs for kettle etc.? Thanks. Excellent video btw.
It can be extended, provided the protective device (fuse, circuit breaker) is suitable for the cable. If it's 2.5mm², usual choices would be a 16A or 20A. Additional sockets also require RCD protection.
John Ward thank you
Can use use a distribution board ( plug on neutrals ) as a consumer unit ( Schneider Acti9 )
Yes. A kit to convert them to single phase is available.
For radial I believe you use 4mm cable ? And what does the RCBO do , I did not really grasp that ? tks
RCBO is a circuit breaker and RCD combined into a single device.
Almost all circuits are radials, cable size required depends on the rating of the circuit breaker or fuse.