Extractor fan and light

[ban-all-sheds]

Now you're just being silly. A relay as an isolator or a DP switch for the light would be simpler and more robust than a capacitor, which would have to be rated at 250V, able to pass 3-5A, have an exceptionally low impedance at 50Hz (<10 ohms):

not age, not leak etc. Oh - and it would have to have some magical way of allowing current to flow in both directions when the pullcord switch was closed and in neither direction when the momentary switch was closed. Not sure how it could tell which condition was which when it saw an alternating potential across it though.....

Finally I can't believe that NICEIC, or the IEE would be happy with a capacitor in series in a current-carrying conductor - they should, as I would be, concerned about what it might do if exposed to the full PSC of the circuit....

 

[AlanE]

Plus an electrolytic capacitor would go BANG!!!! They are polarity consious and need a DC voltage present for them to work.

A simple solution would be to use a two pole ceiling switch for the light. Wire live to one, output of which feeds in of second and fan then out of second to light.

This effectivly means the two poles are connected in series with the fan connected to the junction together with momentary switch connection.

Then the light would only come on when the light switch was operated.

Alan

 

[ban-all-sheds]

Yup - that would be another workable way to use a DP switch. I'd suggest that if you do that you document it, as it could confuse the hell out of some future DIY-er.

 

[Big_Spark]

I was waiting for someone to point that out

Sorry, just have a silly moment


Now having my serious head back on.

As I stated in an earler post, the best solution to this is to wire a humidistat to the fan and give it automatic operation. It saves any messing about with multiple switches and all the other crap associated with it. In this way it does not matter if you forget to turn the fan on or for that matter means you do not need a timed fan that will shut off just when you need it most because the timer shut if off.