Temporary circuit - max amps to faceplate?

[Elecpleb]

I have set up a sub main supply to my shed as follows:
32A MCB on main fuse board
6mm T&E
Sub-mains board (B&G with RCD (40A 30mA))
32A MCB
4mm T&E @ 3m
Terminating at X2 double sockets

I have been told the sockets could melt as they will only be rated for 13A plugs, not a 32A radial in 4mm T&E. Is this true?

ps this is only a temporary set up for power tools, while I renovate the shed. I plan long term 2.5mm ring off a 20A.

 

[buzzlightyear]

I have been told the sockets could melt as they will only be rated for 13A plugs, not a 32A radial in 4mm T&E. Is this true?

Which idiot told you that. Considering a 4mm on a 32 amp on the circuit.
What is the loading or on that circuit..
The sub board should be a 64amp, but the design should be better.

 

[Spoon]

I have set up a sub main supply to my shed as follows:
32A MCB on main fuse board
6mm T&E
Sub-mains board (B&G with RCD (40A 30mA))
32A MCB
4mm T&E @ 3m
Terminating at X2 double sockets

I have been told the sockets could melt as they will only be rated for 13A plugs, not a 32A radial in 4mm T&E. Is this true?

ps this is only a temporary set up for power tools, while I renovate the shed. I plan long term 2.5mm ring off a 20A.

Welcome to the forum mate.
Does your main consumer board have RCD protection?
If it's just for power tools then I would recommend a 20A in the shed instead of a 32A breaker as you have move selectivity.
Who told you that the sockets would melt? They won't.

If it's just temporary then why not just use an extension lead to the shed until you do the proper job?

 

[wheeto]

To be fair, this set-up could exceed the faceplate's rating. 26A (and, of course, with no limit on duration) will exceed the rating of a double faceplate but that's not an issue with the arrangement in this scenario, it's an issue with BS1363-2.

 

[Strima]

To be fair, this set-up could exceed the faceplate's rating. 26A (and, of course, with no limit on duration) will exceed the rating of a double faceplate but that's not an issue with the arrangement in this scenario, it's an issue with BS1363-2.

So how does that work on any other socket circuit on 32 amp OCPD? Why haven't all our houses burnt down due to this problem?

 

[wheeto]

So how does that work on any other socket circuit on 32 amp OCPD? Why haven't all our houses burnt down due to this problem?

Your first question is making exactly my point: I think the regs are inadequate. And the answer to your second question is, I suppose, "luck."

 

[Elecpleb]

Welcome to the forum mate.
Does your main consumer board have RCD protection?
If it's just for power tools then I would recommend a 20A in the shed instead of a 32A breaker as you have move selectivity.
Who told you that the sockets would melt? They won't.

If it's just temporary then why not just use an extension lead to the shed until you do the proper job?

Thanks Spoon.
Yes, 63A RCD on the main board.
Power tools up to 4200W. I agree with the breaker size, I just used what was supplied for now as I already had the 4mm
I did use the extension lead... its 45m and unreeling and reeling seemed more effort than the temp run, also meant I could the lighting straight away as that’s permanent.

To be fair, this set-up could exceed the faceplate's rating. 26A (and, of course, with no limit on duration) will exceed the rating of a double faceplate but that's not an issue with the arrangement in this scenario, it's an issue with BS1363-2.

Hi Wheeto.
What does this mean to exceed this rating? As in, what would be the consequence of this? At the moment I’d just like to be able to use sockets out there until I insulate, ply and then surface mount the permanent supply.

 

[wheeto]

Hi Wheeto.
What does this mean to exceed this rating? As in, what would be the consequence of this? At the moment I’d just like to be able to use sockets out there until I insulate, ply and then surface mount the permanent supply.

Use them - I didn't mean to imply that your set-up was any more dangerous than every other double socket in the country on a 32A breaker (radial or ring final). I was just making the point that none of them are properly rated for two appliances at 13A load each! Sorry for any confusion.

 

[Midwest]

Your first question is making exactly my point: I think the regs are inadequate. And the answer to your second question is, I suppose, "luck."

Some (twin) sockets are actually only rated to 20A, 16A & 4A, if I recall. Some sockets manufacturers, MK for example rate theirs at 13A & 13A per (twin) socket. So with the latter, why would it cause a fire on a 32A supply?

 

[wheeto]

Some (twin) sockets are actually only rated to 20A, 16A & 4A, if I recall. Some sockets manufacturers, MK for example rate theirs at 13A & 13A per (twin) socket. So with the latter, why would it cause a fire on a 32A supply?

The fact that MK have recently chosen to exceed the statutory minimum requirements on their logic plus series is great, and their outlets will be safe on the 32A supply.

Others don't and, therefore, won't. It doesn't affect my opinion on the standard itself.

Just out of interest, @Elecpleb , what brand and model faceplate have you used?

 

[DPG]

If the main board is RCD protected then there is no point putting one in the sub board.

I think I would get a sparky in for this to be honest.

 

[Elecpleb]

The fact that MK have recently chosen to exceed the statutory minimum requirements on their logic plus series is great, and their outlets will be safe on the 32A supply.

Others don't and, therefore, won't. It doesn't affect my opinion on the standard itself.

Just out of interest, @Elecpleb , what brand and model faceplate have you used?

These are MK Logic Plus model no K2747RPWHI5PK

If the main board is RCD protected then there is no point putting one in the sub board.

I think I would get a sparky in for this to be honest.

Well the RCD was supplied with the sub board, and I dont think I will need the space, so I may as well leave it in. I think the sub board is necessary too, to divide up a main circuit, second circuit and lighting; main circuit for the work bench and second circuit for wall sockets for heaters, chargers etc

 

[wheeto]

These are MK Logic Plus model no K2747RPWHI5PK

You're in luck goes to show it's worth paying for quality! The answer to your original tl;dr is: not necessarily, but yours can.

 

[Vortigern]

The good thing about tools is that usually you can't use more than one at a time so no fear of overload there. The sockets could melt and sometimes do but that is usually putting 6kw on the socket and loose connections. The MCB is there to protect the cable actually, more than the accessory. You are just at the top end of 4mm on a 32a MCB so I would not worry about it. Depends a bit on how you installed it such as through insulation and in the sunshine wont help it will derate the cable. Mind you tools up to 4.2kw could be a problem for the socket. 18a is at the top end of the socket rating, per socket now that could make them melt.

 

[MJPD29]

Are you sure you understand what you are doing? How do you intend on drawing 32a through a socket outlet? They are generally rated at 20a so not even suitable for 2x13a plugs. RCDs in series is a bad idea also. No need for the second one if already protected at origin, however a bad design.

 

[Lucien Nunes]

There seems to be a lot of random nonsense in this thread, not all of it intentional, but clouding the issue of the original question.

Protecting double BS1363 socket outlets using 32A MCBs is normal and standard and 100% compliant.

There are lots of other things to say but that is the important one and I can't be bothered to haggle at the moment.

 

[Elecpleb]

The good thing about tools is that usually you can't use more than one at a time so no fear of overload there. The sockets could melt and sometimes do but that is usually putting 6kw on the socket and loose connections. The MCB is there to protect the cable actually, more than the accessory. You are just at the top end of 4mm on a 32a MCB so I would not worry about it. Depends a bit on how you installed it such as through insulation and in the sunshine wont help it will derate the cable. Mind you tools up to 4.2kw could be a problem for the socket. 18a is at the top end of the socket rating, per socket now that could make them melt.

The max usage would be two tools, a 2000W router and 2200W extractor so used simultaneously. The cable is surface mounted as its temporary.

Are you sure you understand what you are doing? How do you intend on drawing 32a through a socket outlet? They are generally rated at 20a so not even suitable for 2x13a plugs. RCDs in series is a bad idea also. No need for the second one if already protected at origin, however a bad design.

Not intending on drawing 32A through it, the consumer unit came with the MCBs and RCD supplied, and I already had 4mm T&E. My question was this suitable as a temporary solution, out of convenience, not design.

There seems to be a lot of random nonsense in this thread, not all of it intentional, but clouding the issue of the original question.

Protecting double BS1363 socket outlets using 32A MCBs is normal and standard and 100% compliant.

There are lots of other things to say but that is the important one and I can't be bothered to haggle at the moment.

Thanks, that was the gist of it

 

[Dave OCD]

To the OP , please correct me if I'm wrong but your initial post gave me the impression that you think a 32 amp MCB will somehow push that amount of current through its connected sockets. That is utter nonsense .

 

[littlespark]

Split that 4200W likely max load across two different double sockets.

As others have said, the faceplate may only be tested to 20A across both outlets.

Also what others have mentioned, the most likely cause of melting would be a loose connection or low quality materials.

 

[Elecpleb]

To the OP , please correct me if I'm wrong but your initial post gave me the impression that you think a 32 amp MCB will somehow push that amount of current through its connected sockets. That is utter nonsense .

No, I was questioning what had been impressed upon me, which was that a current up to 32A at the rear of the faceplate could cause issue.

Split that 4200W likely max load across two different double sockets.

As others have said, the faceplate may only be tested to 20A across both outlets.

Also what others have mentioned, the most likely cause of melting would be a loose connection or low quality materials.

Yes that’s the plan, got two double sockets so good to go for now. Triple check connections.

Thanks all, think we’ve ticked the box here