Converting storage heater switch to socket

Triffle · 10 Oct 2021

Hi all, long time no see

We will shortly be removing a storage heater we no longer need. It is currently connected to the storage heater CU by means of a 20amp DP switch. At first we assumed this switch would just become redundant.

But I've had an idea. Is there anything wrong with replacing this switch with a 1-gang socket?

I am aware that it will only work at night!
But, I think it would be perfect as a socket to use for charging my wheelchair, which needs to be charged overnight when it has been used (or at least once per month).

So - would there be anything against doing this? Would we be allowed to have something non-storage-heater on this circuit? (Not only of course from a safety/regs POV but would it be seen as 'cheating' the heat part of our electricity bill, to use it for something non-heating?

)

Assuming it's ok to do it, onto the specifics:

The storage heater CU it attaches to only has MCBs, no RCDs - would we need an RCD socket? (something like this maybe: https://www.screwfix.com/p/crabtree-instinct-13a-1-gang-dp-switched-passive-rcd-socket-white/197hv)

I would actually prefer a socket with a neon light (like this https://www.screwfix.com/p/mk-base-...cket-white-with-neon-with-white-inserts/835pf) so it would be easy to see when the socket is 'live' - but it seems I can only get an RCD socket or a neon socket, not both.

(I'd actually, if I were really picky, just have an unswitched socket with neon, but I can't seem to find such a thing).

flameport · 10 Oct 2021

It can be changed to a socket.
Doesn't matter whether it's on the overnight circuit, other than it will only be on overnight.
There isn't any restriction on what electricity is used for, and no way anyone could know anyway.

The new socket must have RCD protection, and that will have to be in the consumer unit.
Changing the MCB to an RCBO may be an option.
RCD socket outlets are not suitable.

Triffle · 10 Oct 2021

Thanks, that makes sense.

Our main consumer unit has MCBs and RCDs but the two consumer units for the storage heaters only have MCBs. Here's a photo of the storage heater CU:

Do these look like we could replace the relevant one with an RCBO? Is that something an electrician would need to do?

EDIT: A quick search finds this, is this the sort of thing? (This looks to be the same overall shape as our MCB although I appreciate shape isn't necessarily the only consideration - this was just a very quick search).

https://www.screwfix.com/p/wylex-16a-30ma-dp-type-b-mini-rcbo/8541x

Triffle · 10 Oct 2021

Also just so I understand - why is it that an RCD socket outlet isn't suitable for this proposed work? This switch / proposed socket is the only thing on its circuit so I thought the RCD would have been fine there.

I see it is also possible to get RCD FCUs - would one of those be any better? (In which case I'd then need a new socket attached to that!)

(Hopefully this post doesn't come across the wrong way - I just genuinely want to understand why it must be RCD in the CU and not at the socket).

Taylortwocities · 10 Oct 2021

Triffle said:
is this the sort of thing? (

Yes. That is what you could install. Plus a socket, of course!

flameport · 10 Oct 2021

That RCBO should be a direct replacement, unless that consumer unit has a balcony type busbar, in which case a new comb busbar would also be required, about £10.

RCD sockets, FCUs and similar are all made to a particular standard, the latest version of which inexplicably states that if they are to be used, RCD protection is also required in the consumer unit.
That makes them entirely useless.

An alternative may be to relocate the cable for that outlet to the other consumer unit, so it's on permanently.

Sureitsoff? · 10 Oct 2021

if you really want an unswitched socket with a neon you could use one of these
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwjMkcippMDzAhUaiFwKHQzRDuQQFnoECAUQAQ&url=https://www.diy.com/departments/mk-white-neon-locator-switch/53970_BQ.prd&usg=AOvVaw0LCTZUHuf-ix_Tyo3Esnh5
sandwiched twixt unswitched socket and wall

Triffle · 10 Oct 2021

flameport said:
That RCBO should be a direct replacement, unless that consumer unit has a balcony type busbar, in which case a new comb busbar would also be required, about £10.

RCD sockets, FCUs and similar are all made to a particular standard, the latest version of which inexplicably states that if they are to be used, RCD protection is also required in the consumer unit.
That makes them entirely useless.

An alternative may be to relocate the cable for that outlet to the other consumer unit, so it's on permanently.

Ok thanks very much for the explanation; that does indeed make RCD sockets entirely useless!

I'm not sure if I really want to go replacing/relocating things in consumer units so I don't know if this idea has any legs after all. It was nice in theory

Sureitsoff? said:
if you really want an unswitched socket with a neon you could use on of these
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwjMkcippMDzAhUaiFwKHQzRDuQQFnoECAUQAQ&url=https://www.diy.com/departments/mk-white-neon-locator-switch/53970_BQ.prd&usg=AOvVaw0LCTZUHuf-ix_Tyo3Esnh5
sandwiched twixt unswitched socket and wall

Ooh I like that, thanks!

EFLImpudence · 10 Oct 2021

flameport said:
RCD sockets, FCUs and similar are all made to a particular standard, the latest version of which inexplicably states that if they are to be used, RCD protection is also required in the consumer unit.

I thought we had discussed that and deduced the reasons for believing what you say were not valid.

Adam_151 · 10 Oct 2021

Triffle said:
Thanks, that makes sense.

EDIT: A quick search finds this, is this the sort of thing? (This looks to be the same overall shape as our MCB although I appreciate shape isn't necessarily the only consideration - this was just a very quick search).

https://www.screwfix.com/p/wylex-16a-30ma-dp-type-b-mini-rcbo/8541x

Close, but no Cigar, You'll likely find that board has what Wylex term a balcony busbar (strip of copper with U shaped slots in, that slide around the terminal screw on the base of the MCB), The newer mini rcbos only have a facility to fit on a PIN based busbar that goes into the rising clamp terminal. The dual RCD boards went over to the pin shaped busbar quite some time ago, where as the boards with only a single bank of circuits (either RCD main switch, or isolator) retained the 'Balcony' style up until quite recently, and they were still in the supply chain at the time the new mini rcbos came out... that caused a bit confusion!, the newer boards had the L suffix

Page 37 here: https://www.electrium.co.uk/media/20180806154618_0_WY2394a_Wylex_DCP.pdf (Its not especially clear though but the pictures expain what I'm taking about)

Triffle · 10 Oct 2021

EFLImpudence said:
I thought we had discussed that and deduced the reasons for believing what you say were not valid.

Ooh, do tell me more please! I'd love it if I didn't have to change anything in the CU.

EFLImpudence · 10 Oct 2021

https://www.diynot.com/diy/threads/summerhouse-outbuilding-wiring-thoughts.572568/#post-5017070

Triffle · 10 Oct 2021

Well that was quite a read. I'm not sure I'm any clearer though!

I'll give it another read tomorrow with a fresh brain.

In the meantime thanks to all for contributions/help. Much appreciated.

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Converting storage heater switch to socket

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