EXTENDING RADIAL CIRCUITS - ADDING LIGHTS TO SOCKET CIRCUITS - HOW MANY SOCKETS? - BREAKER? - CABLE?
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- เผยแพร่เมื่อ 12 ก.ย. 2024
- This LearnElectrics video will look at how we may extend radial circuits. We published a short video on this subject several years ago and since then there has been a new set of regulations, and perhaps too, it is time to update, extend and improve the content. Social media always has lots of questions on radial circuits and we can address some of these here. We will begin by looking at types of radial circuits, what they do and why, and then move on to look at each of the common types.
We then examine socket circuits with different breaker and fuse sizes and different cable sizes. What works, what is safe and most importantly, how to avoid installing unsafe circuits. If we are extending a radial circuit, what can we do? What cable sizes should we consider, when should we be thinking about refusing, and what size cable is matched to what size fuse or breaker. Is there a maximum number of sockets for a circuit, what are the rules for the use of single sockets and double sockets.
Can we add lights to socket circuits, what are the methods and how do we make them safe. What is an FCU and when should I use a switched FCU - and do they affect cable size?
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great feedback, really appreciated, thank you.
@@learnelectrics4402just curious. With an FCU spur from existing socket circuit. Why does it have to be 2.5mm between the spur-socket box and the FCU? Can it not be 1.5mm the entire way??? Would really appreciate thoughts on permissability
@@learnelectrics4402as i patiently continued watching i found my question answered. Definatley the best channel as the previous guy said!!!
Amazingly clear and useful as always! Thank you
My pleasure and thank you for your comments and support. Dave.
Another great tutorial David, many thanks for taking the time to make them, best on youtube. Happy New Year.
Thank you John, appreciated, Dave.
Clear and lucid lesson, as always. Thanks Dave. New Year's greetings to all the sparkies...visiting this site.
Happy new year to you too, have a great 2024.
Thanks for all your videos over the year. I've learned so much from you. Hope you have a successful 2024.
thank you, appreciated, Have a great 2024 yourself.
Brilliant content, I have been in the industry for 27 years, keep it up 👏🏼👏🏼👏🏼
Thank you, will do. Lots more to come.
Great video. Well done Dave. Thanks for all the hard work 2023
Thanks Brian. It all starts again in 2024. Have a great New Year. Dave.
David is an amazing Tutor and has a profound ability to be able to break down advance theory into small bite-size parts making learning fun and easy Thanks David.
Happy new years David and to all the sparkies
Happy to help and thanks for the feedback. Happy New Year to you too. Dave.
What a great video Dave. I’m learning more and more from you.
Glad to hear it and thanks for the feedback, appreciated.
Thanks, Dave, you have a way of demystifying these things
Thank you and thanks for watching.
Excellent explanation, and graphics Dave-best wishes for the new year-🎉
Many thanks David and have yourself a an excellent 2024. Dave.
Very informative video as usual...
Thanks again, really appreciated.
Superb vid as always David. A good video would be about Quinetic wireless switches and wiring
Thank you. Yes, it is on the list. It will happen. Dave.
Top drawer presentation Dave.. I still work with lads who insist on calling ALL circuits 'Ring' Hope you had a great Xmas.. Happy new year mate.. 👍
Yes, I've come across this. thanks for watching. Dave.
Yes really best video sharing
Thank you, appreciated comments. Dave.
As always cheers Dave 👌👍happy new year to you and family 🎉
Thank you Martin. have a great 2024 yourself. Dave.
Excellent - thank you for a great explanation.
Glad it was helpful and thanks for watching.
Great videos, so helpful. Thanks and have a great 2024.
Lets all have a super 2024 Michael. All the best. Dave.
This is great, thank you. Best wishes for 2024.
And you too, have a great 2024.
Love these videos, thank you 👍
Glad you like them, thanks for watching. Dave.
I've been spending some time on a house that my daughter has just purchased and while doing various jobs I've had a look at the cabling. I've noticed that the socket circuit, one covers the whole house, comes out of the consumer unit in 4mm t+e then goes to about four 32 amp junction boxes, one after another. From these junction boxes, 3 or so separate spurs in 2.5mm t+e then feed individual sockets placed around the house except for one spur which is run in 4mm t+e which feeds not only the first socket but also another one too in a different room which is placed on the other side of the wall behind it. The whole of the house is wired in the old colours and is also multi-strand cable, even in the 2.5mm. I can't make my mind up whether to swap the existing 32 amp MCB for a 20 amp one just to make the circuit safer for her or to leave the existing 32 amp breaker in place in case the breaker starts tripping with only a 20amp one in operation. I'm not an electrician, I'm a Joiner/carpenter but I do enjoy watching your videos.
So many variables here, and if its old colours that makes the circuits at least 18 years old. When were they last inspected and tested. Take a look at these two viseos that should help. Thanks for watching. Dave.
Radial circuits
th-cam.com/video/wKCxgEWleHk/w-d-xo.html
Cable size
th-cam.com/video/VtTUkUpQ-Rc/w-d-xo.html
The vid said a spur can only have one socket on it unless an FCU is fitted off the 4mm spine.
So it does not conform to the 18th, but may have been compliant when installed many moons ago. Thec32A mcb will *not* protect the 2.5mm cable.
Yes drop the mcb to 25A or 20A. Or better still fit an RCBO or better again an AFDD.
Shared 👍
Thank you, appreciated.
A 13A FCU can have multiple sockets on a 1.5mm cable. Fine.
Can you have a 13A mcb at the consumer unit serving a 1.5mm radial?
A 10 amp mcb at the consumer unit with 1.5mm cable is ok. This is what we would do for larger lighting circuits. Thanks for watching.
@@learnelectrics4402
Thx. 1.5mm taking into account derrating can take 14.4A to 20A according to a quick look at the tables. So a 13A breaker at the CU supplying sockets on a 1.5mm radial is fine. Depending on the cable run even a 20A. I know a ring is a minimum of 2.5mm cable and max of 32A breaker.
So a radial supplying upstairs with no heavy appliances is fine on 1.5mm. If it had a 16A breaker it could do two 1.8kW fan heaters at 230v. So two 1.5kW fan heater in case the gas boiler is down, can be run and still spare capacity for the computer, etc.
Sometime we overkill in the UK. Once again, thx.
@@learnelectrics4402
With LEDs, a 10A lighting circuit will be more a commercial job these days.
Great Video Dave, with some additional information for myself that I haven't seen before ..
Could you please explain what would you white down in a Minor Work certificate for a editing light point from socket circuit.Would you write down supplied from 3A fused spur or origin 32A/20A breaker in fuse board?What would Zs be calculated for lighting point as well?
Thank you once again for spending your own time to creating another knowledgable video!
Put the 3 amp as the circuit protection for the lighting. There is an entry for BS1362 fuses for Zs final circuits in the Regs book on page 67. Thanks for watching. Dave.
A wee question ; in the lighting circuit were both 1.5 & 1mm is used , how does that work when calculating with the equation ? ie what is the Iz value ?
The 1.0mm Iz for the lighting example is still much higher than the 6A rating for the over current protective device. Older lighting circuits were traditionally wired in 1.5mm but with modern low energy lamps this is easily covered with less expensive 1.0mm cable.
A perfect answer from Mike. take a look at table 4D5 on page 456. You will see the ratings under Ref method C
Thank you Mike. Great support. Dave.
@@learnelectrics4402 Thank you Dave, for a brilliant resource and the easy understanding that you have distilled as a seasoned spark. Best wishes for 2024.
Can anyone explain the physics or logic in reg 433.2.2 please ? In both cases the load on the spur is limited by the FCU. Max fuse in FCU is 13A which we know can pass steady current of 21A all day long. What does 3m have to do with this ? Surely the 2.5mm should be standard?
The regs permit this if there is no branching. personally, I'd stick with 2.5 but I need to say if there is an option.
@@learnelectrics4402 I’m with you on this one. The IET have some interesting peculiarities and I like to challenge to learn more.
I like how we here in the UK explain a normal (radial) circuit as if it's not the norm. Like it's surprising that it doesn't go back to the unit from the last point. Ring circuits are the oddballs!
I agree, but so many have grown up with ring circuits that its difficult for a small number to think of a socket circuit being anything else than a ring.
Sorry, but 3 seconds in and the distorted audio levels have put me right off. It’s probably a great video, but I’ll never find out and I’m sure I’m not the only one. What a shame 😕
I'll check it out. Thanks for the info.
I’m watching it and it’s fine on my device 👍
Fine on mine too. Must be your phone / computer