New fan but something wrong....

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Evening,

Hopefully someone can point me in the right direction. Replaced the cloakroom extractor time fan today and added an isolator. All other wiring is existing and nothing else was changed but something is wrong.

Light switch ON + fan ON - works ok
Light switch off fan stays on timer, but light stays on, but only dim plus timer does not stop fan. fan continues to run.

Wiring is as follows...

Cable from CU to junction box. Splits to the light switch, plus a mirror then continues to next light.
At light switch COM = live from JB + Perm live to fan isolator. L1 = switched live to light fitting + switched live to fan isolator
At fan isolator L1 = switched live L2 = permanent live N = neutral all coming from light switch then same again from isolator to fan.
Cable from fan to isolator to switch is 3C&E. Black with brown sleeve = Switched live. Brown = Live, Earth and Grey with blue sleeve = Neutral.
All neturals at light switch connected to a WAGO connector.

Is there anything wrong with this as it seems to me that a live and switched live might be back to front?

Thanks.
 
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Sounds a bit odd. I'd disconnect the Fan wring in the first instance and see if the light switches on/off ok? There isn't a humidstat in the Fan too is there - if it does and is on the lowest setting that could make a Fan run without stopping.
 
Fan is timer only. When i disconnect the wiring to the isolator the light switches on/off correctly.

This is essentially how it is all connected
chockblockhar1w.gif
 
And has black been used as switched live and grey as neutral at the light switch?
 
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And fan switch is actually connected as you say?

Have you got the old fan?

Do you have a multimeter?
 
Fan switch is connected as per instructions. L1 = switched live, L2 perm live, L3/N = Neutral. I did wonder if the switch was faulty but seems unlikely. Dont have the old fan but it was connected the same way just without the isolator switch. Yes I have a multimeter in the garage somewhere. That was my next move.
 
Just connect the wires from the isolation switch together and if it then works properly, the switch must be faulty.
 
Ok, so i bypassed the fan isolator and it made no difference. But, looking at how everything works, it appears that with the fan isolator off, the fan doesnt work as expected and the light works normally. When the fan isolator is turned on, it brings the light on and the fan without pulling the light switch on. Checked all the wiring and I cant find anything in the wrong place?
 
At the pull switch, are you certain the light live wire is with the fan black wire
and
the feed live live wire is with the fan brown wire?

That's the only thing that could be wrong there I should think.
 
Last edited:
You also mentioned a junction box. Have you disturbed this?

The junction box should have all the browns together, all the blues together, all the earths together - based on what you have described.
 
Yes, Im pretty sure, I will check that tomorrow though just in case. Thanks to everyone for the help so far.
 

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