In message ,
the_constructor writes
In my bathroom, inherited from previous occupiers, I have a low voltage
timer fan:

http://www.screwfix.com/app/sfd/cat/...92597&id=14750

The timer is up in the loft.

In the loft is a junction box for the bathroom light and the timer for the
fan above is wired up as follows.

Constant live from live input to junction box.
Switched live from return on light switch
Constant neutral from neutral input to junction box

thus, when light is switched on and off, the fan keeps going for a set
period of time.

What I would like to do is electrically isolate the timer from the lighting
circuit, for safety.

Any ideas please as to how or what I should use to do this.

Thanks in advance


This is the normal way of doing this, it switches the switched and
permanent supply to the fan as well as the neutral, so it is fully
isolated from the mains.


http://www.screwfix.com/app/sfd/cat/...02755&id=51728

--
Bill