Electric shower extractor fan

[GB]

Hi, I am planning to fit an electric shower and would like to install a timed extractor fan at the same time. I would like the fan to operate during and after the shower is switched on, and NOT every time the light is switched on.

I have run a dedicated circuit from the consumer unit (RCD protected) to the electric shower via a ceiling mounted isolator switch. I would like to know if it acceptable to wire the extractor fan from the shower isolator switch? And would I need a fuse between the isolator switch and the extractor fan? This is the only way I can think that will allow the timed extractor fan to operate during and after the shower is switched on, and not every time the light is switched on.

My major concern is safety so if this is in anyway dangerous please let me know and I will install a separate isolator switch for the extractor fan running from the ceiling rose.

Thanks

 

[breezer]

yes it would be highly dangerous, because you would need to have a separte fuse to isolate you fan (as you said) trouble is you will not be able to get two 10mm cables into the switch, you can also now get "humidity fans" that start and stop acording to the moisture in the air, i think i have seen them at screwfix

 

[ChrisR]

Dead reliable, humidity switched fans - every time it rains they come on!

Would it be possible to switch a fan from a PIR detector pointing at the shower? IP rating sufficient??

Also for the intrepid - you can get flow switches (as used in boilers) which you could put in the water supply to the shower to switch on the fan. If it were say 12Volt and say under the bath or above the ceiling I don't see a problem, but a sparky might?

Or a pipe stat on the waste to detect hot water? OK maybenot