For anyone who thinks wiring is too easy to be left to the professionals. In our bathroom the fan permanent live is supplied from the socket circuit (admittedly from a fused switch unit next to the sccket in the cupboard under the sink) and the switched live is from the lighting circuit. I don't suppose this is totally forbidden, but it seems a bit eccentric to me, especially if one thinks the fan might be isolated by the (two pole) FSU.
Or not isolated depending on the circuit that switches it on from a different live source.
I believe you are supposed to have a 3 pole isolator that does both lives and neutral with a 3mm gap in the switch.
A necessity that only arises if you want the fan to be switched by the same switch as the light switch.[1] We want a separate switch, but I think we will have the 3 pole isolator anyway in case a future resident wants it changed to one switch.
[1] Unless you are happy for the bathroom light to go out when you isolate the fan, which is considered bad practice for some reason.
Isolating the fan will not turn off the light.
The switched live to the 3 pole isolator comes from the light switch but the supply to the light is taken off before the isolator.
Yes, it is totally forbidden!
521.8.2 says L +N of each final circuit shall be electrically separate from those of every other final circuit.There will be more, but ICBA to look them up now.
Suffice to say, it can be dangerous how yours is, and should be rectified to make it safer, i.e, get the permanant live from the same circuit as the switched live.
Well, exactly. But you might *choose* to use a two pole isolator
*before* both the light and the fan. That would work fine, except you would have to work on the fan in the dark or bring your own light. I was just emphasising *why* you need a three pole isolator.
There is no need. Said fan previously discharged into the (almost except at the eaves) closed space between two rafters and T& G below and slates above. Now it has Kingspan resting on it and a membrane under the slates, and I have therefore disconnected it. A work in (not much) progress as we now have an unconnected ventilator in the roof not far away.
I must say I power my fan, loo, and shower light from a single switch, but there is a separate strip light for the bathroom area which illuminates both areas well.
I'm wondering why the loo is powered, an electric fencer for those that pee without due care & attention?
NT
Er, yes it is!
A fan with switched and permanent live ought to have a three pole isolator.
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