Extractor fan tripping

[UK.will]

Hi. I have an extractor fan in the bathroom which is switched on/ off by a humidity sensor. The humidity sensor is wired into the lighting loop for the upstairs at my house. Whenever a light is turned on (where the light is connected to the same loop as the humidity sensor) this also trips the sensor and turns on the extractor fan. I figure the humidity sensor is very sensitive?

I guess if I wire the humidity sensor into a different lighting loop, say the loop for the downstairs lights, then the extractor fan will trip on whenever a light on the downstairs loop is switched on or off. I will have the same problem I have currently.

I could wire the humidity sensor into the fuse box on its own fuse but this seems like a lot of work.

my other idea was to buy some sort of filter/ damper to wire between the lighting loop and the humidity sensor to soften out any spikes caused by the lights on that loop being switched on/off.

Any ideas if a damper/ filter exists and where I could find such a thing? Would this work or is there any easier way to stop the humidity sensor tripping?

 

[Marvo]

Are you an electrician Will?

 

[Octopus]

Are you an electrician Will?

Marvo, you know the answer to this, so please move it to DIY pronto!

 

[midgetman]

I figure the humidity sensor is wired wrong

 

[Richard Burns]

Welcome to the forum.
It is possible that your fan is a humidity and timer fan, i.e if the light is turned on the fan will come on for a while irrespective of the humidity then stop.
the humidity sensor will operate to switch on the fan whether the ligth is on or off.

The other alternative is that the humidity sensor is set too low and is just triggered into operating by the fractional voltage dip of the light coming on.
The last thing may be that the humidity sensor is only switched on when the light is on and they can take time to settle when first powered up.