5 minutes ago, Tizer said:

If the fan has an overrun then that is quite frightening if someone who does not know what he is doing ever tries to change it.

Overrun as in staying on after the light is switched off?  Yes it had that.  I say 'had', because a new fan was also fitted to pass the new regs, despite the old one appearing to work ok.

I always wondered how the overrun worked (but clearly not enough to look into it!)...wasn't sure if it had a capacitor that released power after switch off, or if it kept pulling mains power and had some sort time delay switch?

1 minute ago, TomsFocus said:

Overrun as in staying on after the light is switched off?  Yes it had that.  I say 'had', because a new fan was also fitted to pass the new regs, despite the old one appearing to work ok.

I always wondered how the overrun worked (but clearly not enough to look into it!)...wasn't sure if it had a capacitor that released power after switch off, or if it kept pulling mains power and had some sort time delay switch?

They have a timer triggered by the light being used, the fan also has a permanent live to it which runs the fan.

3 minutes ago, MarksST said:

They have a timer triggered by the light being used, the fan also has a permanent live to it which runs the fan.

Thanks Mark!

Well, had no idea my original 'simple' question would have sparked off such an interesting thread! Good to know we have so many knowledgeable electricians as members here... As someone who can just about to wire a plug, I've learned alot... 😁

1 hour ago, TomsFocus said:

I say 'had', because a new fan was also fitted to pass the new regs, despite the old one appearing to work ok.

The old one may not have had the correct IP Rating for the zone that it is in, either that or if the Landlord is not a private one then whoever is in charge of maintenance is ripping them off.

I've had experience of that for other things as well, especially Services.

5 hours ago, StephenFord said:

Afraid I don't have 'isolator' switches, they weren't part of build code when house built 30 years ago...

That's a shame. I'm afraid I'm out of suggestions that don't involve additional wiring ☹️

2 hours ago, StephenFord said:

Well, had no idea my original 'simple' question would have sparked off such an interesting thread!

No pun intended of course 😉

 

Yes, it's an old thread, but as I started it, I feel entitled LOL I was replacing an LED bulb in the kitchen, you know, the ones that last 10000 hours! (). On the way, I thought I would try it in the downstairs toilet - it worked perfectly! No flickering whatsoever, and also allowing the extractor fan to work too. I suppose it's like using a CanBus bulb in a car where it shows no faults. So all those suggestions of a re-wire, or new fittings, no need. Just a nice new modern bulb in a 30 year old fitting!