FCU for bathroom fan?

Question

I'm going to put an extractor fan in my bathroom (a humidistat model I think). I'll wire it as a spur from the lighting circuit, or possibly from the ring on the floor above depending on what looks easier when I take up the floorboards upstairs. I'll put in one of those three-pole isolators. With this wiring I could preumably get away with a two-pole, but I like the three-pole ones with the little shower piccy ;-) I can see no need to fuse the spur (with an FCU) and would have thought that the isolator alone would be enough, but I thought I'd better check here.

And is it OK to put the isolator in the bathroom next to the fan (which will be up by the celing about 1.4m from the bath and not near any other watery equipment) or should I put it outside the room altogether?

Actually one final question occurs to me - neither circuit is RCD protected. I know in a perfect world at least the ring should be, but in terms of pure regs compliance is it necessary for the fan (in which case I shall be forking out for an RCD FCU)?

BigWallop · Accepted Answer

A fused spur from the ring or lighting circuit will allow the fan to blow its own fuse and not anything else if a fault occurs. If you can install just a flex outlet plate in the bathroom and a Switched Fused Spur unit outside the bathroom, you'll be able to switch the fan off safely from outside the wet area before doing work on the fan.

Make sure you rate the fuse to what is specified on the fan instruction manual.

John Rumm · Answer

Little "fan" piccie shurley? (shower piccie would kind of suggest shower isolator, which would be two pole)

Most fans will require a 3A fused supply.

As the isolator is a pull cord one, and it sounds like you are installing it in zone 3, then yes. You can stick the FCU next to it while you are at it!

If we are talking about an upstairs ring circuit, then it is not a given that it requires RCD protection, though that will partly depend on the type of power supply to the property.

If you had a electric towel warmer in there, then you would need the RCD. In the case of just the fan, then no (in fact if the fan is powered from the lighting circuit, you would typically not want that on an RCD protected supply anyway).

Martin Pentreath · Answer

Thanks BigWallop and John. Sounds like I'll be putting in an FCU then. Can I clarify something? I wasn't intending to use a pull-cord isolator because I don't like the dangly cord which (I hope) will only get used about once a year. I was thinking of one of these

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that go up by the ceiling in zone 3 along with the FCU or does it have to go outside?

Thanks,

Martin

John Rumm · Answer

Accessories are allowed in zone 3 (as long as they are not socket outlets or provide a way to connect portable appliances), so yes you should be able to use one of those.

(Hopefully the high risk scenario of being naked and wet in the bathroom does not apply to when you are doing fan maintenance!)

Dave Stanton · Answer

The mind boggles !!Dave

FCU for bathroom fan?

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