Putting bathroom heater on shower circuit?

sparkwright · 20 Jan 2017

Based on the limited info we have on the place, John's idea about inserting a fused spur before the loft socket, then feeding the heater from that certainly sounds good.

Of course, if we were actually in the house no doubt we could find an even better way.

Personally I think it's always a bad idea to tag things onto shower circuits, partly because the next man wouldn't expect to find anything else, partly because it adds more load to the circuit, and partly because it's fiddly to add anything else to a thick shower cable.

I usually cringe at any extra unexpected wires in a shower switch, and would cringe even more at seeing a junction box with something teeing off from a shower cable.

It's rare to see things added to shower circuits, and when you do it has DIY written all over it.

Incidently, are you certain the shower cable is 10mm2?

propertydev83 · 20 Jan 2017

Thanks everyone for the input.

He's going to go with a 13A RCD FCU in the loft before the socket, then continue the spur radial 2.5mm from the loft socket to a 13A DP FCU on the wall outside the bathroom, then continue the 2.5mm spur back through the loft to the heater.

Or, as suggested change the loft socket to an RCD socket, then have a 2.5mm flex cable from a plug to the 13A DP FCU outside the bathroom, and another 2.5mm flex to the heater.

JohnW2 · 20 Jan 2017

propertydev83 said:
He's going to go with a 13A RCD FCU in the loft before the socket, then continue the spur radial 2.5mm from the loft socket to a 13A DP FCU on the wall outside the bathroom, then continue the 2.5mm spur back through the loft to the heater.

You wouldn't need that second FCU - just a switch or a single socket, depending upon whether you wanted to hard-wire the heater or plug it in.

propertydev83 said:
Or, as suggested change the loft socket to an RCD socket, then have a 2.5mm flex cable from a plug to the 13A DP FCU outside the bathroom, and another 2.5mm flex to the heater.

As I've already said, I think that running 'fixed wiring' from a plug is 'orrible ('nasty')!! - but, if you really wanted to do that, you wouldn't need the second FCU (there would be a fuse in the plug).

Kind REgards, John

sparkwright · 20 Jan 2017

It may be an idea to have the RCD somewhere more accessible should it trip. Not that it would trip much, though could prove frustrating for anyone trying to find it.

If the socket is ALREADY protected by an RCD then no need to add another, assuming it works.

If not, perhaps just the fused spur unit for the heater could be the RCD one, leaving the socket unprotected as before. However, by having to fit a fused spur unit before the socket, one could argue that should now be RCD protected to be in line with regs.

JohnW2 · 20 Jan 2017

deadshort said:
i would never install a socket in the bathroom.

Nor would I (and, unless one has an enormous bathroom, the regs don't permit it) - but I didn't say anything about "in the bathroom".

Let's face it, you're the one who suggested plugging the heater into a socket in the loft

Kind Regards, John

JohnW2 · 20 Jan 2017

sparkwright said:
It may be an idea to have the RCD somewhere more accessible should it trip. Not that it would trip much, though could prove frustrating for anyone trying to find it.

As you say, one would only expect it to trip once in a blue moon (if ever), so it wouldn't be a major inconvenience (particularly since it is not supplying 'crucial' loads). Also, we don't know how accessible (or inaccessible) the loft is - it could be very 'easy'.

sparkwright said:
If not, perhaps just the fused spur unit for the heater could be the RCD one, leaving the socket unprotected as before.

I don't see how, regs-wise, you could have a socket and an FCU connected to the same (otherwise 'unfused') spur. Am I missing something?

Kind Regards, John

sparkwright · 20 Jan 2017

JohnW2 said:
As you say, one would only expect it to trip once in a blue moon (if ever), so it wouldn't be a major inconvenience (particularly since it is not supplying 'crucial' loads). Also, we don't know how accessible (or inaccessible) the loft is - it could be very 'easy'.
I don't see how, regs-wise, you could have a socket and an FCU connected to the same (otherwise 'unfused') spur. Am I missing something?

1) Yes, the loft could be very easily accessible for all we know.

2) Yes, you are missing something. I meant in the loft change the socket for regular fused spur unit, which will then serve the loft socket and then on to an RCD fused spur above the outside of the bathroom door to serve the bathroom heater.

It would mean the loft socket would remain unprotected RCD-wise.

deadshort · 20 Jan 2017

JohnW2 said:
Nor would I (and, unless one has an enormous bathroom, the regs don't permit it) - but I didn't say anything about "in the bathroom".

Let's face it, you're the one who suggested plugging the heater into a socket in the loft which is not a bathroom ………….DS

Kind Regards, John

JohnW2 · 20 Jan 2017

sparkwright said:
2) Yes, you are missing something. I meant in the loft change the socket for regular fused spur unit, which will then serve the loft socket and then on to an RCD fused spur above the outside of the bathroom door to serve the bathroom heater. It would mean the loft socket would remain unprotected RCD-wise.

Oh, I see. Was the idea of that just to get the RCD more accessible (even though it involves two FCUs in the path to the heater)?

When you previously said "leaving the socket [in the loft] unprotected", I thought you meant unprotected by a fuse, as well as unprotected by an RCD - hence my comment about two things connected to the same ('unfused') spur!

Kind Regards, John

deadshort · 20 Jan 2017

JohnW2 said:
to a single socket for the heater.

So, just for clarification if this socket is not in the bathroom where is your socket ?

DS

sparkwright · 20 Jan 2017

JohnW2 said:
Oh, I see. Was the idea of that just to get the RCD more accessible (even though it involves two FCUs in the path to the heater)?

When you previously said "leaving the socket [in the loft] unprotected", I thought you meant unprotected by a fuse, as well as unprotected by an RCD - hence my comment about two things connected to the same ('unfused') spur!

Kind Regards, John

Yes, it was solely to put the RCD in a more accesible and visible place.

My description could have been written more clearly.

JohnW2 · 20 Jan 2017

deadshort said:
JohnW2 said:

Let's face it, you're the one who suggested plugging the heater into a socket in the loft

Click to expand...

which is not a bathroom ………….DS

You do make it rather difficult to quote your messages

Anyway, you appear to have missed my point. I obviously was not thinking of a socket in the bathroom, not the least because, as I implied, few are big enough for it to be 3m from bath/shower. I was therefore thinking of a socket (just) outside of the bathroom and, in case you came back and said that would be inconvenient or untidy, pointed out that you had suggested plugging it in to a socket in the loft!

Kind Regards, John

JohnW2 · 20 Jan 2017

deadshort said:
So, just for clarification if this socket is not in the bathroom where is your socket ?

Somewhere a darn sight closer to (and more convenient for) the bathroom heater than the loft

Kind Regards, John

deadshort · 20 Jan 2017

Mm, thanks for the clarification

…… lovely job !

DS

oldbutnotdead · 20 Jan 2017

propertydev83 said:
Thanks everyone for the input.

He's going to go with a 13A RCD FCU in the loft before the socket, then continue the spur radial 2.5mm from the loft socket to a 13A DP FCU on the wall outside the bathroom, then continue the 2.5mm spur back through the loft to the heater.

Or, as suggested change the loft socket to an RCD socket, then have a 2.5mm flex cable from a plug to the 13A DP FCU outside the bathroom, and another 2.5mm flex to the heater.

RCD protection on the bathroom heater is a good thing- but having to get into the loft to reset it is maybe less good (depends on your loft access I suppose).
Depending on the design of your consumer unit, you'd be better off (IMHO) putting the whole circuit on an RCBO and going with the FCU etc in the loft.
And do make sure your bathroom is big enough so that the heater doesn't fall within any of the prescribed Zones (or the work becomes notifiable). Also worth checking the IP rating of the heater- chief concern, can it be safely operated with wet/damp hands?

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Putting bathroom heater on shower circuit?

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