Mike Clarke wrote:

On 11/03/2019 15:48, Roger Hayter wrote:

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.

http://wiki.diyfaq.org.uk/index.php/...h_no_timer.png

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.


--

Roger Hayter