old immersion heater circuit

chrisw99 · 6 Sep 2018

Last year we had a combi installed, so the 30+ year old system of tank/hot water cylinder was removed leaving us with a nice empty big airing cupboard at the top of the stairs I'm currently in the process of sorting out with shelving etc.

It's got me wondering what we should do with the old immersion heater wiring. The setup is: dedicated fuse switch on the consumer unit labelled "immersion". An old fashioned switch on the kitchen wall labelled "immersion" with a red light which comes on when it's on. A standard 1-gang switch in the airing cupboard. And from the switch ran the immersion heater.

I flicked the switch off on the consumer unit when the immersion was removed, and forgot about it till I've started the renovation of the airing cupboard, and it's got me wondering what I should now do having a handy powered switch in there.

My first thought was to run a power socket into the attic, as I don't have power up there and I'm always having to run long extension cables up to it when working in there. Is this a feasible thing to be considering? The annoyance would be that to turn on the socket in the attic would need the immersion switch on the kitchen wall to be on.

Any other suggestions/comments?

Taylortwocities · 6 Sep 2018

Assuming you want to use the existing cables.
You could loop out the kitchen switch and put a blank plate over it. Same with the switch in the airing cupboard.
Then your supply wont be switched off.

EFLImpudence · 6 Sep 2018

chrisw99 said:
My first thought was to run a power socket into the attic, as I don't have power up there and I'm always having to run long extension cables up to it when working in there. Is this a feasible thing to be considering?

Yes, good idea.
You will have to (and want to) have an RCD on the circuit for sockets.

Are there RCDs in the consumer unit already?

The annoyance would be that to turn on the socket in the attic would need the immersion switch on the kitchen wall to be on.

Or - handy to turn off when not in the loft.

chrisw99 · 6 Sep 2018

EFLImpudence said:
Yes, good idea.
You will have to (and want to) have an RCD on the circuit for sockets.

Are there RCDs in the consumer unit already?

Or - handy to turn off when not in the loft.

Don't think so. It's on the right hand side of my RCD on the consumer unit which I'm fairly sure is the unprotected side.

Right hand side has: Heating/Freezer, Lights, Immersion, Upstairs Sockets, Shower.
Left hand side has: conservatory wiring, outside garage light, garage, downstairs sockets, kitchen sockets

I presume I could just use one of these instead though...

https://uk.rs-online.com/web/p/rcd-sockets/4319320/

EFLImpudence · 6 Sep 2018

chrisw99 said:
Don't think so. It's on the right hand side of my RCD on the consumer unit which I'm fairly sure is the unprotected side.
Right hand side has: Heating/Freezer, Lights, Immersion, Upstairs Sockets, Shower.
Left hand side has: conservatory wiring, outside garage light, garage, downstairs sockets, kitchen sockets

Ok. but I would have thought the shower would be on the RCD side.
Maybe it's not an electric shower.
Is that still used now you have a combi? If not the cable may already be in the loft.

I presume I could just use one of these instead though...

You could if you just want the one socket.
There are several options.

I was thinking more of lights as well.

chrisw99 · 6 Sep 2018

It's an electric shower. How do I figure out which is the RCD side...

EFLImpudence · 6 Sep 2018

The ones to the left with the red labels.

That side is a bit of a mixture to say the least.

chrisw99 · 6 Sep 2018

I guess it fails current regulations having the upstairs sockets and the shower on the non RCD side. Never really looked at it in detail before till today. Should probably get that sorted one day.

But back to the original question - non-RCD so needs to be an RCD socket in the loft. We already have lights in the loft which are part of the upstairs lighting circuit, just no power sockets.

EFLImpudence · 6 Sep 2018

chrisw99 said:
I guess it fails current regulations having the upstairs sockets and the shower on the non RCD side. Never really looked at it in detail before till today. Should probably get that sorted one day.

Yes, but probably ok when done - but odd.

But back to the original question - non-RCD so needs to be an RCD socket in the loft.

Yes.

chrisw99 · 6 Sep 2018

We moved in in 2001 so it pre-dates that, a quick google shows the requirement for an RCD on a shower was in the regs update of 2008.

Taylortwocities · 6 Sep 2018

chrisw99 said:
It's an electric shower. How do I figure out which is the RCD side...

Press the test button on the RCD. The circuits that lose their power are the protected ones! Simples!

PS I hate that mix of different maker’s MCBs. I’ll bet the inside is a right horlicks. I suggest having a new CU fitted on your list of things to have done.

chrisw99 · 6 Sep 2018

Taylortwocities said:
Press the test button on the RCD. The circuits that lose their power are the protected ones! Simples!

PS I hate that mix of different maker’s MCBs. I’ll bet the inside is a right horlicks. I suggest having a new CU fitted on your list of things to have done.

The mix is easy to explain, they were all the same when we moved in but the downstairs sockets occasionally tripped, and the garage always tripped when both the washer and dryer were on together. Turned out they were both 10A MCBs, so got replaced.

The Wylex on the far left was an empty socket and was used for the extension we had a few years ago.

Taylortwocities · 6 Sep 2018

Easy to explain??? Its the sign of a cowboy. Is someone allergic to Proteus or something?

I would be concerned about the history of this. If the original MCBS were 10A it was for a reason. Maybe the cables can only handle 10A. Seen any smoke when the appliances are running? Do you have a fire extinguisher?

chrisw99 · 6 Sep 2018

Taylortwocities said:
Easy to explain??? Its the sign of a cowboy. Is someone allergic to Proteus or something?

I would be concerned about the history of this. If the original MCBS were 10A it was for a reason. Maybe the cables can only handle 10A. Seen any smoke when the appliances are running? Do you have a fire extinguisher?

The advice at the time was always use Hager to replace Proteus as they're identical but better quality. It's a long time ago but I'm sure I was going to buy the Proteus only to read all the reviews saying buy the Hager instead. Seems like there's been similar advice in the intervening years...

https://www.electriciansforums.co.uk/threads/what-breakers-fit-proteus-boards.28397/

The 10A to the garage socket is literally about two feet of cable from the CU, and is no different to any of the other cables feeding the higher rated circuits. The problem was it just fed a solitary socket in the garage. Must have been good enough for the previous owner, but then we come along and plug both a washer and a dryer using a 2 way adapter, it kept tripping.

Taylortwocities · 6 Sep 2018

Love them or loathe them, consumer units are type tested with their own manufacturer's products in them. Its a bit like you putting after market Chinese brake pads in your Jaguar. How they will laugh as you pile into the chemists shop at the bottom of that steep hill.

chrisw99 said:
the garage socket is literally about two feet of cable from the CU

Maybe, but what SIZE is the cable? Maybe its only big enough for 10amp! A socket isn't a fixed load, as you have discovered.

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old immersion heater circuit

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