Bathroom light/extractor fan problem

[magill]

Evening all

Posted this in blogs by mistake!!

Bit baffled with current situation, maybe someone here has experienced before?
Just wired up a bathroom light with the extractor fan as normal practice. All works fine until light is switched off and during the 15 minute over run the light blinks on and off every few seconds. when the fan is switched off at the isolater the blinking stops, so it definately has something to do with the fan wired via the switch live. Any thoughts before i start fault finding?

Thanks

 

[Rockingit]

May be I am not understanding what you are trying to explain.

As the switched wire connects the 230V from the switch to the lamp, to supply the L to the Lamp to light it, and then this switched L is fed to the fan. So if this switched wire connects/shorts to the permanent L in the fan, then surely that permanent L connects through the switched L to the lamp supplying it with 230V. The Lamp already has a permanent N, and now has a L.

I am sure if the Permanent L and Switched L were connected/shorted any where then the lamp would stay on.

You are correct, hence my previous edit.

 

[Moses]

You are correct, hence my previous edit.

Thankyou.

 

[Guitarist]

Not being obtuse. sorry if it comes across as that way.
But if the switched wire was touching the permanent then the lamp would stay ON? or not?

After a 4 year apprenticeship and over 20 years in the field, there have been many times when I have come across cables "touching" without being connected, causing intermittent supplies to loads. This can often be caused by vibration, and would result in a "flicker" in this instance.
If this is a difficult concept for you to understand then I can only apologise for confusing you with my suggestion.

 

[magill]

Replaced the CFL with a low watt halogen and hey presto! all works fine according to plans. Absolutely no flicker. Big thank you to Moses for the idea, saved a lot of hassle. This is one of those scenarios that nobody can teach you so many thanks to all members for input.

 

[trev]

I had this problem once on a job for a council in a school, after a lot of head scratching it turned out that my mate had marked up the cables wrongly. Stripped everything out, traced which cable was which reterminated and it worked fine.

 

[Moses]

Replaced the CFL with a low watt halogen and hey presto! all works fine according to plans. Absolutely no flicker. Big thank you to Moses for the idea, saved a lot of hassle. This is one of those scenarios that nobody can teach you so many thanks to all members for input.

another satisfied punter!