bathroom fan help please

[mamamaka]

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Hi I want a timed fan to run
off an isolater switch and not through the light,

at the mo i have 3core
and earth running from the fan to the isolator, and then i want to wire into a
circuit which already exsists as there is a spur from the lighting circuit to
run a bathroom cabinet light...

Can i take it off there? and if so how
do i pick up the switch live and the live?

all help appreciated

)


​

 

[trev]

Your isolator will, no doubt, be triple pole. Where locally can you pick up a perm live a switched live a neutral and a cpc.
You will only be able to pick these up at the cabinet light if it's 3 plate wired. NB your extract fan will be designed to have an over run after the light is switched off

 

[JUD]

Is there a reason you don't want to run it with the light??

 

[mamamaka]

Hi Trev, the bathroom cabinet light is run from 1mm T&E, so can i use that?

 

[jpm646]

Just link live to SL on the out side of the isolator and remove the SL from the light and switch and put to earth or connector blocks. This will make the isolator you on off switch for the fan

 

[mamamaka]

Hi Jud, just because i cant get to the rose with the wire, the ceiling is patterened and the floor above is glued laminate and cant be lifted, i just want an easy alternative )

 

[mamamaka]

sorry jpm646, can you elaborate as i dont understand

 

[trev]

If it's 3 plate then yes, subject to the maximum Zs reading of course. Assuming the existing circuit meets the maximum allowable Zs then it doesn't really matter what csa the cables are but by the sound of your question you will need perm live, sw live and N so you may need to rethink where you're going to get your feed to the isolator and transformer if one is needed. If it's not 3 plate then do as JPM suggests

 

[JUD]

Just link live to SL on the out side of the isolator and remove the SL from the light and switch and put to earth or connector blocks. This will make the isolator you on off switch for the fan

That would activate the fan OK but would be no good for timer over-run as fan needs permanent live to keep running. When isolator is switched off it will cut power.

Not sure why you would want to remove sw. line from light and switch and certainly wouldn't want to be putting them TO EARTH!!!

 

[trev]

That's the problem Jud but it sounds to me that he's not too fussed about having the over run which kind of defeats the purpose of installing an extract fan but who am I to criticise

 

[mamamaka]

Just link live to SL on the out side of the isolator and remove the SL from the light and switch and put to earth or connector blocks. This will make the isolator you on off switch for the fan

please elaborate i am being slower than normal tonight

 

[mamamaka]

how do i get a sl and a live and n from the t&E circuit?

 

[mamamaka]

That's the problem Jud but it sounds to me that he's not too fussed about having the over run which kind of defeats the purpose of installing an extract fan but who am I to criticise

so i need to find a way of going through the ceiling rose to make it work properly then....is that what you are saying?

 

[Strima]

so i need to find a way of going through the ceiling rose to make it work properly then....is that what you are saying?

Ideally yes if using a fan with overrun.

 

[JUD]

so i need to find a way of going through the ceiling rose to make it work properly then....is that what you are saying?

In a word....YES as this is usually the only place that has all 3 connections (unless it's looped at switches)

 

[Richard Burns]

I assume you want to run the fan without overrun and just switch the (3pole?) isolator on and off to switch the fan on and of . If this is the case then you only need permanent line neutral and cpc and link the permanent line and switched line in the fan connections.

If you want the fan to have an overrun then you would need another switch in the circuit and take the permanent line and switch line from this switch to the isolator. Then turning on the switch would turn on the fan and turning off the switch would allow the fan overrun. The isolator would stay on all the time.

Either way you can take the supply from the supply to the cabinet light.

 

[Swicade]

Take the fan back and get a non timed fan....once thats done alot of the confusion will be dealt with as your then only playing with L/N/E through the isolator.

If for some reason it has to be a Timed fan then as previously mentioned you can ONLY come off a ceiling rose (3 plate system) to make the timed fan function property....giving you Live/SwitchLive/Neutral/Earth.