Bathroom light flickering with switch in off position

[gmc600]

Hi, looking for some advice. My bathroom light tripped one of the two RCDs and when I reset it I noticed the light (4 LED downlights actually) flickering when the switch is in the off position but only if extractor fan switch is on. The extractor fan usually runs whenever the lights are on.

What are the most likely causes/suggested troubleshooting steps?

Thanks!

 

[endecotp]

switch is in the off position but only if extractor fan switch is on. The extractor fan usually runs whenever the lights are on.

I’m unclear about how this works - you say that the extractor runs when the lights are on, but you also mention an extractor fan switch. What switches do you have, and how to they behave?

 

[sparkwright]

Have you had any electrical work done just before this happened?

 

[ericmark]

Capacitive and inductive linking can cause lights to stay on dim or flash, but I would have thought the fan would have reduced this, not increased it.

So I wonder what makes you think the bathroom lights tripped the RCD, although earths need running to lights, in the main there is little in a lamp which can cause earth leakage.

So feel there is something you're not telling us?

 

[Harry Bloomfield]

So I wonder what makes you think the bathroom lights tripped the RCD, although earths need running to lights, in the main there is little in a lamp which can cause earth leakage.

So feel there is something you're not telling us?

I think he may be saying that - instead of the lights coming on, when switched on, they are just flickering. That suggests the driver, or what ever, is faulty, and what caused the RCD trip originally. Over to the OP?

 

[Murdochcat]

Seen this in my time. Extractor fans ceiling mounted had water collecting in the cover , enough to do precisely what you describe

 

[gmc600]

Thanks for the quick replies. So there’s an extractor fan switch above the light switch, what’s supposed to happen (and has for 9 years) is that if the extractor fan switch is on the the fan will run immediately when the light is switched on and will then continue to run for a short period after the light is switched off.

We usually leave the fan switch off as it’s annoying that it runs immediately when lights are switched on, and only switch it on if someone is having a shower. That’s what I did yesterday, switch on the light and then the fan, which immediately tripped the RCD.

No recent electrical work (last was about 2 years ago).

The suggestion that water ingress has caused this does seem likely as water ingress broke our extractor fan in the other bathroom a few years ago.

If I leave the extractor fan switch off then the lights work normally.

 

[endecotp]

Is the fan switch a “fan isolator”, i.e. a very wide switch?

 

[gmc600]

Yes that’s correct, and I just took off the fan cover and it’s full of water!!

 

[Harry Bloomfield]

Yes that’s correct, and I just took off the fan cover and it’s full of water!!

Dry it out thoroughly, and it might work again, but how did it manage to get so very wet? Is that a wall fan, or a ceiling mounted fan?

 

[gmc600]

Ceiling mounted, the water seems to just collect in the pipe above the ceiling which eventually floods the fan unit. Exact same thing happened a few years ago in other bathroom. Just a long period of condensation ending up in the pipe I guess.

 

[Harry Bloomfield]

Ceiling mounted, the water seems to just collect in the pipe above the ceiling which eventually floods the fan unit. Exact same thing happened a few years ago in other bathroom. Just a long period of condensation ending up in the pipe I guess.

I read somewhere, that you can buy, and fit condensate traps for these ceiling mounted ducted fans. Maybe worth investigating?

 

[Collectors]

Extractor Fan Condensation Trap With Overflow

Fitting this extractor fan condensation trap will help to catch any moisture and remove it from the ducting run. Suitable for use with 110mm solid ducting, the trap is designed with an overflow pipe connector for easy draining.• Designed for use with 110mm solid ducting• Catches and removes...

www.toolstation.com