Extractor Fan Switch.

perspicacious:

Agreed, but some tenants use the isolator to stop the noise so the landlord's building suffers the consequences that the Building Regulations foresaw......

Staying in a B&B a couple of years ago, well some time before lockdown ...


Hostess kindly explained the function of the switches on the bedroom side of the stud wall betwixt same and the bathroom. Yes, they could have been in the bathroom outside the zones! So you get up for a pee in the night (as those of us of a certain age tend to do) and on completion switch off the fan isolator so that it does not drone on for the next 20 minutes.


In fairness, there would be no nasty niffs (unless taking penicillin) or damp, so no need to run on.

Colin Haggett:

geoffsd:

whjohnson:

3 pole switch required in order to isolate the fan/SELV transformer etc.

But if, as stated by perspicacious, the fuse covers both the permanent live and switched live then a three-pole switch is not necessary; a switched double-pole FCU would suffice.

The idea of the fan isolator was to keep the lights on when servicing the fan.

Just what sort of servicing does a 4 inch bathroom fan require? And, aren't there lead lamps or torches available? If "serviced" in the daytime and the room has a window, there is no need for the room light for "servicing" the fan, whatever that entails?


Also Chris, the fusing down to 3 Amps is to comply with manufacturer's instructions for some fans.


Sometimes customers buy their own fans and ask me to install them. If the fan needs a 3 Amp fuse then this arrangement seems to satisfy that requirement.


I recently installed a customer's fan in a small shower room. I ran the supply via a fused connection unit for the lights and shower fan. That was easy as the room was being refurbished and the ceiling was down. But sometimes it is not so easy if the lighting is on a B6 M.C.B. and wired three plate, or looped at switches.


Z.

Is there a conventional TP fan switch that satisfies the second paragraph of 537.3.2.3?

Will ON and OFF suffice Bod?

Knightsbridge Square Edge 10A 3 Pole Isolator Switch (SN1100) at UKES (ukelectricalsupplies.com)


But some fans are maintenance free, so is there a need for such a switch?


Z.

perspicacious:
The idea of the fan isolator was to keep the lights on when servicing the fan.

geoffsd:

perspicacious:
The idea of the fan isolator was to keep the lights on when servicing the fan.

That really is a ridiculous reason.


What about if you want to service the lights with the fan on?


 

It’s not for me to question the reasoning but the the idea was that you could maintain the fan whilst keeping the lights on in a bathroom without a window.