"Owain" wrote in message
. ..
PeteZahut wrote:
Im looking at the possibility of buying an extractor fan with built in
spotlight like the ones used in bathrooms.
Secondly, the ones I have been looking at require 4 wires and an
isolating switch.
The four wires are one permanent live to enable the fan to run on when
the light goes off. One live, one neutral (switched live?) and one earth.

Live, switched live, neutral, earth.

I gather the isolating switch is to enable work to be carried out on the
fan if needed but how would this be done. Dont all isolating switches
only have three connection points?

Fan isolators have three poles (L, SL, N - the earth is *never* switched).

Is it just the permanent live which needs to be
fitted to this switch?

Assuming you don't want to use the timer facility, supply the fan with
Live and Neutral, and link the PermanentLive and SwitchedLive terminals at
the fan. If you are taking the supply from a socket circuit, use a Fused
Connection Unit fused at 3A.


Thanks so far Owain, what i was hoping to do was just replace the pendant
light which is in the computer room, this would give me a switched live,
neutral and earth, I was then going to take the permanent live from the feed
to the lights and use a shower type pull cord switch or just one of the wall
type shower/cooker switches which would be out of sight but accessible if
needed, but also left on . Could i do this, I'd then have my twin and earth
and strap a red wire to this. If I can do it that way, how would I wire the
pull cord switch?
Would i be wrong in thinking that just having a switch to isolate the
permanent live will be ok, the lights obviously are covered by the consumer
unit. I would want the fan to run after the light has been turned off.
Pete