dennis@home wrote:

On 11/03/2019 14:41, Roger Hayter wrote:
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.
--

Roger Hayter