SPURS ON SPURS Extending Circuits
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- Опубликовано: 15 май 2024
- It often happens that a customer, or even yourself, wishes to add just one more socket to a circuit.
Perhaps it is to make it easier to plug in the computer without having to keep using extension leads, or an extra socket on the workbench in the garage.
Which circuits can I extend from?
What do I need to consider?
Can I have three extra sockets?
Can I spur off the water heater?
In this video we will answer many of these questions and there are lots of possibilities and of course, a right and wrong way to do it.
We will hopefully give you the information that you are looking for, the answers to some of your questions and show you how to extend circuits safely and in accordance with the Wiring Regulations.
We have also included reference tables to help you when you extend circuits and add sockets.
Remember that electricity is dangerous. Always safely isolate before starting work and if in doubt, stop, and seek advice from a competent person.
To view all our videos, click on the following link
/ @learnelectrics4402
To view a list of all our LearnElectrics videos, click on the link below.
There are many videos on many electrical topics including Installation, Part P, 18th Edition, Testing, Certification, Lighting, Sockets, Ring Circuits and much more.
ruclips.net/channel/UCYaJQnpO4XAp0yCgqzMkmfA
This is the best explanation I have ever seen before. Well done. IN this one one videos there is more than what people teaches in two years, you have basically cut through the entire regulation in one lecture. Now you are the sort of person who should be teaching 2391 and no one will fail. The reason so many people fail that test because wrong people are teaching it. Many teachers know they subject but how to pass it on is no joke.
I know it's kinda randomly asking but do anybody know of a good place to watch new series online ?
@Jaxx Mateo I would suggest flixportal. Just google for it =)
@Korbin Elliot definitely, I have been using Flixportal for years myself :D
@Korbin Elliot Thank you, signed up and it seems to work :) I really appreciate it!
As usual, very great presentation. Thank you. Looking forward for the next lesson.
Thank you Omar, really appreciated.
Our next video on Thursday is about bathroom zones. We hope you enjoy that too.
Dave
Clear, simple, really, really helpful
Thank you
Thanks Andy, great feedback. Dave.
This is very helpful; just what I needed. Thank you.
Glad we could help. Lots more to come.
Excellent information as always. Thank you. 👍
Thanks Mike. Your positive comments are valuable to us. Dave.
Thank you, answered all my questions plus a couple I hadn't even thought of!
Brilliant, that's what it was made for. Thank you.
These videos are fantastic!. Thank you very much for producing the content!
Thank you Coert, thanks for the great feedback. Appreciated. Dave.
This video is absolutely brillant, thanks so much for producing this!
Glad you enjoyed it and keep watching, lots more to come.
Hi Dave
You are by far the best teacher with excellent teaching skills.
I have always enjoyed listening to your videos as I always learn something new.
Please keep the videos coming and if possible try to make them more.
I really appreciate your help
Cheers
Fantastic feedback, we really do appreciate your comments. We are upping our videos to Monday and Thursday now. Spread the word about LearnElectrics, it all helps us to feel the hard work in making the videos is worthwhile. Thank you so much. Dave.
Excellent balance of theory, regulations and practical scenarios. Very clear.
Glad you enjoyed it. Lots more to come. Dave.
Thank you again for another perfectly executed video
My pleasure and thanks for watching. Dave.
thank you so much! this video is extremely well put together and you teach very well. Keep up the good work ;)
Thanks, will do David. I appreciate your comments and support.
You always been a great help.. Cheers dave
My pleasure. Its all about helping each other. Dave.
As always thank you sir for this educational clip🙏
My pleasure, glad it helped.
Learn more of this channel than I did in uni. So underrated! Thankyou
That's a really nice comment, Thankyou. Dave.
Brilliantly explained thank you so much for creating a clear concise explanation of electrics.
Glad it was helpful, thanks for watching. Dave.
Brilliant lecture, very well given, thanks a lot
Most welcome Fernando, thanks for watching.
Thanks for this. So helpful
Thank you Jim, appreciated. Dave.
Slow and clear presentation thanks
Thanks for the positive comment and thanks for watching. Dave.
Top video again Dave, thanks for sharing mate
Thank you Dan, a very welcome comment. Bathrooms on Thursday this week. Dave.
Thank you, very helpful.
Great feedback, thank you very much. We keep trying our best. Dave.
Really helpful. Thanks a lot
Glad it was helpful, appreciated feedback.
I’m just really learning the English electrical system and your videos are invaluable.
Great to hear that. If you learn the British Regs, you will easily adapt to any other system. Same principles world wide.
This is very useful to someone like me to get ready to do Inspection and Testing soon I really appreciate your effort and time to put this video Thanks again
Mohamed, have you watched our video on inspection and testing assessment tips.
Use the link below. Dave.
ruclips.net/video/nZF0UXh7GT0/видео.html
Thanks, great info.
Glad it helps, thanks for watching. Dave.
Thank you for another sterling vidio. I was always told that you can not run a spur from a spur like you can't run an extention lead from an extention lead. Great video very useful information. Thank you.
Glad the video helped, Sean, its all about limiting the current in normal use.
Lots more to come. Dave.
Great and very informative video! 👌
Brilliant feedback Marcin, appreciated. Dave.
Very informative clearly described.
Glad you liked it, appreciated.
A really great video - subscribed to show my support of this great content
Much appreciated, lots more to come. Dave.
Excellent video
Thank you very much. Appreciated.
Thank you, ans excellent 👌👍
You are welcome, thanks for watching.
Amazing content👌
Thank you, appreciate your comments. Dave.
These vids are amazing.
Thank you so much, so very happy you are finding them useful. Dave.
Love it!!
Great feedback. Thanks for the support. Dave.
Great video. Just one point regarding 3kw water heating radial circuit. 16A breaker in the consumer should be sufficient to provide via a double pole switch rather than an FCU which would have only a 13A fuse. The water heater could be on for hours and may overheat the 13A FCU.
Excellent point Andy. Thanks for your contribution, appreciated.
Thanks for such a brilliant informative video.
I haven't found a video for this as yet but how would I go about extending the ring circuit to add in another 6 sockets
Good question. I will do a video on extending the ring in the next few days.
It's on the list now, watch this space and thanks for watching Dean.
Dave.
Great video, clear a lot of misconception on the Internet by various electricians who have they own personal subjective views
Thanks for the great comments. I try and keep my own views out of the videos and just include the standard information and how to interpret what the Regs are telling us. Thanks for watching. Dave.
Great video, thanks. In the case where you show a 2.5 sqmm cable spur from a consumer unit with a 32 amp MCB, I am surprised that this is allowed. If the cable rating is 21 or 27 Amps depending on fixing method, I am surprised it can be adequately protected by a 32 Amp MCB.
Even if it was a double socket, would you really plug two 13 amp kettles into it, or run two 3 bar room heaters? And if you did that comes to 26 amps and 2.5 cable will take 27 amps Ref method C. More likely you might have a kettle plugged in for three minutes to make a cuppa, and a computer at 5 amps, so only 18 amps at times, often less. Diversity of use. So that covers overload. If their is an earth fault the current will be hundreds of amps and the disconnect time less than half a second so the breaker will trip before the cable is damaged. Hope this helps. Dave.
@@learnelectrics4402 Totally agree that in practice it's not a problem, but just a bit surprised that it's allowed by the regs, which, as we know, can be pretty strict! Would a knowledgeable building control officer accept it, I wonder?
Hi Dave, thanks for the video; I have been studying a few of them to try to educate myself. I wonder if you could advise what would happen on the circuit at 5:00 if each of the sockets was loaded with a)1.25KW and b)2.75KW? if we assume the resistance of the circuit is equal on each leg and measure the current in between the circuit breaker and the first socket?
For a) I would say that we could estimate the current as being:
1.25KW x 1000/ 230 = 5.4A
Then use this figure to calculate the anti-clockwise current coming from each socket loaded with 1.25KW.
So, (4/5) x 5.4 + (3/5) x 5.4 + (2/5) x 5.4 + (1/5) x 5.4 = 10.8A travelling anti-clockwise at that point.
2.75KW x 1000/230 = 12A
Again, this can be used to calculate the anti-clockwise current coming from each socket loaded with 2KW
So, (4/5) x 12 + (3/5) x 12 + (2/5) x 12 + (1/5) x 12 = 24A travelling anti-clockwise at that point.
If we assumed method 101, could we say that the second scenario is not appropriate as the max. carrying capacity for 2.5mm cable is 21A? and here we have 24A flowing through one section of the circuit?
Thanks in advance.
the regulations assume that we would only heavily load one socket in each double socket. So long as the load is more or less evenly distributed and below the tripping current of the mcb then all should be ok. If you are slightly over, it may take a few minutes to trip. And current in a ring circuit can flow both ways.
Thank you for your amazing videos.
I note that this video says no spurs are allowed from a dedicated circuit (cooker etc), does this include FCU's.
I've had mixed advice about the appendix regarding this being 'guidance' rather than 'regulation', i.e. it can be done but isn't best practice.
Thank you.
A spur to a socket for a built in oven is acceptable, its still part of the cooker circuit. A spur to wall socket is not good practice as this is no longer a dedicated cooker circuit, its now a mixed circuit.
Have a look at this video on kitchen electrics. Thanks. Dave.
ruclips.net/video/bOSMYzXY_Uk/видео.html
An excellent explanation as is the spur on ring circuit one.
I've a couple of questions though on getting power into a conservatory for some sockets and a light (at around the 9:30 mark in the video). I'd like to be able to isolate the power in the conservatory from within the house/lounge so; 1) Can the FCU be located in the lounge rather than in the conservatory? 2) Can the FCU be a switched FCU?
Thanks
Yes to both of those. It would help with future maintenance if there was a note at the CU that the FCU was in the lounge, not the conservatory. Great question, thanks. Dave.
I like it 👏👏👏
Thank you for the great comment. Dave.
I’m adding a outdoor double socket and one security light , I’m taking the power from a socket in the living room , would I add a fcu first or can I go straight from the indoor socket to the outdoor socket , then an fcu off that outdoor socket for the light ?
It sounds like you are installing two accessories David. A double socket and a light. You will need to put the 13A FCU first. If you made the FCU a switchable (preferably without a neon) you could turn the power off to the outside when not needed.
@@learnelectrics4402 thanks for the reply yes I did order a fcu switchable with no neon , is the a reason why you prefer no neon ?
I will install the internal fcu in the living room taking the power off the socket , then drill my hole to the outside for the outdoor socket , adding another fcu next to that for the security light I’m installing , and I’m running nyy-j hi tuff 1.5 3 core into a junction box for the light because the light has a flex . Any advice if you think I’m going wrong would be appreciated
Great video as always Dave, one question that has always bugged me regarding ring final circuits. Despite bs7671 stating that it is permissible, how is a single leg of 2.5mm allowed to connect onto the ring (either directly into mcb or off a socket outlet as a spur) if the overload protection is a 32A mcb? It almost seems contradictory or an exception to the rule???
Looking forward to more content👍👍
Even if it was a double socket, would you really plug two 13 amp kettles into it, or run two 3 bar room heaters? And if you did that comes to 26 amps and 2.5 cable will take 27 amps Ref method C. More likely you might have a kettle plugged in for three minutes to make a cuppa, and a computer at 5 amps, so only 18 amps at times, often less. Diversity of use. Hope this helps. Dave.
@@learnelectrics4402 That is a weird thing as the fixed installation should not rely on what is plugged or protection. The installation relies on the fuses on the plugs. Now I et every country has such peculiarities dictated by practicality in their codes.
The answer is that twin socket can onl have two 13A loads, which is 26A, which is below the 28A that a 2.5 mm^2 cable can take. Also, twin sockets aren't even rated to takes 26A continuously. I seem to recall the British Standard only requires that they don't overheat after 30 minutes with a combined 20A load. In practice, the regs appears to assume that there will not be two 3kW loads continually running on a double socket. Other national regulations seems to have the same sort of assumptions. For example, US sockets are only rated for continual use at 80% of their maximum current carrying capacity.
Hi, great video.
My garage has a radial circuit. Currently on a 2.5mm. My question; can I add two double sockets spurs off one double socket.
So I have one double which spurs to an outside plug, I want to add another double socket daisy chained off the original socket. Is this allowable/ possible?
Yes you can Vijay if the MCB protecting the circuit is 20A or less and you have 30mA RCD protection.
Hi Dave, your videos are very knowledgeable, thanks for that 👍 please could you just confirm for me, I want to add 3 more double sockets in a bedroom on a 20a radial, CAN I DO THIS FROM ANY SOCKET???
If its 20A radial and if it is a 2.5mm T/E then the Regs allow this. Have a look at the left hand drawing on page 506 of the Regs. Thanks for watching. Dave.
@@learnelectrics4402 where will I find this??? Thanks Dave
@@leeholgate8343 In your Wiring Regs book. Dave.
in my kitchen i had a double socket which the kettle and toaster are plugged into, i had a spark install an extra socket beside it. ive took the plates off to check what he had done and the newer socket is a spur as it has one set of 2.5mm cable going into it. now i was wanting to drill out the back of the spur to outside to fit a double external socket to power stuff outside, so now see I would want a fcu fitted before the new double socket. i see from your video the fcu would be the first thing , is adding it to the outside before the new double socket allowed?
The first thing off the ring must be a 13A FCU. Then you can have your internal and external sockets AFTER the FCU. Take a look at this video on the link below.
ruclips.net/video/fj9cc1U9Re0/видео.html
Hi, in my home the upstairs sockets are connected via a 32A ring circuit with 2.5mm2 twin and earth cable. In one bedroom there are two single sockets. I am considering changing both of these sockets to double sockets (no change to the number of "accessories").
One socket has a fused switched spur, which powers an outside lamp, I am considering altering this spur to the following: 2.5mm2 cable going from the (newly swapped) double socket on the ring main, to a 13A unswitched fuse box (spur box), then 1.5mm2 cable going from this 13A fuse to multiple double sockets (radially), from the first of these spurred double sockets after the 13A fuse, I will also have a spur going to a switched 3A fuse box (spur box), which will then go to the outside light, also using 1.5mm2 cable. From what I understand, this meets all of the regulations, do you agree? Thank you
Just for reference, all of these sockets mentioned are for accessories at a desk, all low powered (printers, PC speakers, lava lamp, Alexa etc). Of course they will be protected by the 13A fuse in case of overload anyway.
Have a look at this video, it gives more information on spurs and the all important Zs readings. thanks for watching. Dave.
ruclips.net/video/fj9cc1U9Re0/видео.html
@@learnelectrics4402thank you, from watching that video I think it does meet the regulations.
many kitchen now are not using a the cooker point (ie using gas cookers or just air fryers combo microwaves), in this situtation can the cooker radial circirt be converted to a radial circirt with added sockets with a 4mm cable, ie if the cooker point of connection is removed and converted to a double socket also?
Absolutely it can John. Thanks for watching. Dave.
Hi there, I am curious and wanting to learn more on this subject. I have an engineering background but no electrical knowledge. Are there any books you can recommend? Thanks a lot
There are many books but only you will know which ones are right for you. There are nearly 200 videos on the LearnElectrics channel and they can also be accessed from LearnElectrics.com
Watch the videos and see where your interests lie. Ideally, try and work with someone that is already in the trade. If you can afford a training course then that is always a good thing to do. Good luck. Dave.
@@learnelectrics4402 thanks a lot . I have been watching many of your videos.
After changing a single socket point to double socket, can spur (add) a double socket from this point here? Appreciate a reply.
If you follow the rules yes Jimi. If the changed socket is actually ON the ring then you can add one more to that new socket. It doesn't matter if it is a single or double as long as it is just one moulding. Hope this helps. Dave.
@@learnelectrics4402 thank you so much.
You're welcome.
Hi . Would it be possible to run a dishwasher/washing machine. to a socket outlet from a switched fused spur from the ring main .
Can you plug a washing machine into a ring circuit? Yes you can, so no problem taking it off an FCU/socket. As long as the washing machine load and what is already on the spur is less than 13 amps you will be ok.
It is recommended that any appliance rated at 2kW or above, should be supplied by it's own circuit. Main reason for this is to prevent uneven loading on a ring particularly in the kitchen.
When you say no spurs on cooker radial circuit, does that mean 2 separate 6mm cables cannot be run from the 45amp switch to a built in cooker and electric hob??
If it was me Neo, I would run a 10mm cable to the cooker control switch and then taken the 13A feed to the oven in 2.5mm. If the two 6mm cables are already installed, join them in the CU and at the cooker end and take the 2.5mm feed to the oven from that. As long as the let through current of the combined cables is more that the 45A breaker, you are protecting the cables. Hope this helps. Dave.
@@learnelectrics4402 Spot on! Best to run a 10mm so, Cheers Dave!
At the point we direct add a SPUR to 32A breaker what would be the cable size? It should be 4 mm square d isn't it?
It's all explained in the video Kalum, the sizes and the different locations. Thanks. Dave.
I wonder why you can't have two single sockets on a spur, when collectively they can only take the same amount of current as a double socket. Did the Regs on this change at some point, as I've uncovered two spurs off a single junction box in two places in my house, both done by electricians in the 1970/80s.
I believe the logic behind it is that a double socket should not exceed 20A total load. Two singles, especially if separated by some distance might have two 13A heaters plugged in. Some electricians interpret one double as being the same as two singles, but not according to the regs. we were not as regulated 50 years ago as we are today.
@@learnelectrics4402 - Thanks for clarifying the rule, altho' given the 27A current carrying capacity of 2.5 T&E I'd have thought 2 x 13A fires could be plugged in without risk.
What's the max distance of a 2.5 cable you can add to a spur from the ring socket ?
When adding cable you should not exceed the Zs for that particular circuit.
Have a look at this video, CABLES LENGTH CALCULATIONS and R1+R2, on this link
ruclips.net/video/Qq_9MNH8XxU/видео.html
How can you use 4mm cable on a 32amp MCB when the 101 method says its rated at 27amps if you could help with this one please
Matt, either increase the cable size, reduce the breaker size or lift the cables above the insulation so they are in air. Hope this helps.
I read somewhere that technically we must use the word spur for rings and branch for radial circuits.
Yes, technically correct Sajad. Thanks for watching. Dave.
From the title I was hoping to see the Tottenham 1st team vs the Tottenham reserves. Oh well, I learned some electrical stuff.
Thanks Ollie Sorry about the football, but electrics is a close second. Thanks for watching, Dave.
Thank you so much for your excellent videos. I've watched quite a few of them now :) I had one question actually. When thinking about an FCU in a radial circuit that's been used to step down to a lighting circuit, could you happily spur from the supply side to an electric socket spur? I hope this makes sense. In my mind, it's the same as installing a junction box just before going into the FCU. Essential this is garage power, there's a spur from the house ring main to a fused FCU, that then runs armoured 2.5 cable to the garage into the first socket on the spur. This then goes to an FCU the other end which steps the wire down to 1.5 for a single pendant light (and uses a lower rated fuse to protect the wire, as I learnt from you!). Many thanks and keep the videos coming :)
That sounds good to me Daniel. As long as the Radial cables are protected by a 20A or 16A breaker and 2.5mm in size. The cables after the 13A FCU can be 1.5mm as you say.
Yes, lots more videos to come. Spread the word. Dave.
I've just extended a socket and is voltage reading is 249-252 is this safe.
It's right at the top end of what the DNO can supply. It will vary during the day.
@@learnelectrics4402 I checked today its down to 248.0 volts,thanks for your reply.
@@andyward937 You must be close to a substation.
I can not understand why 1 accessory is permitted. The MCB can not protect that single cable with a smaller size. It can heat up and damage. Is there a logical reason?
Because what is plugged in has a 13A fuse max. Even two plugs equals 26A and the single 2.5 cable is rated at 27A.
Bit dangerous that !
What if someone put a32A device back in again?
Steven, we are talking about sockets here. The Wiring Regulations permit 2.5mm cable for the spur because a plug is fused at 13 amps and if a double socket, would someone put two fully loaded 13 amp appliances into it at the same time. The Regs assume diversity, that not both sockets of a double will be fully loaded. Their rules, we just work with it. Hope this helps. Dave.
@@learnelectrics4402 always thought diversity was for calculating maximum demand and sizing everything!
1mm using method 101 is NOT 13a, it is 10.5a. And in todays construction methods it is quite easy for a cable to become surrounded by thermal installation, in which case the cable is derated by 50%, that's why personally, I would recommend lighting circuits to be wired in 1.5mm, or use a ring circuit and YES ring circuits are permissible on lighting circuits.
Thanks beau.
👍
Thanks for watching, appreciated.
Can't you just do a radial 'Spur' of a ring in 4mm2 and add additional sockets without a FCU since the cable is protected? upto 32amp.
Ring circuits are so pointless and dangerous.
Good question Ciaran, but I can only tell you what the Regs say are permissible. Thanks for watching, appreciated.
@@learnelectrics4402 Technically incorrect. BS7671 states what must be achieved, it does NOT stipulate how it is achieved.
Absolutely no problem at all. What 7671 states regarding a spur from a ring is that the cable must be no less than 2.5mm.
Radial circuit is like having spurs on spurs. How is single piece of cable not overloaded?
If you have done Ib In Iz correctly then the breaker will protect the cable.
@LEARN ELECTRICS thanks for you reply but i still feel like an idiot asking this. What is Ib In Iz?
I was told by an electrician that in ring circuit, we are only allowed 1 spur per socket otherwise it will be overloaded. I wonder why is this not the case with radial circuit? If i do Ib In Iz(whatever that means) correctly, can i have spur on spur in ring circuit?