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Extractor Fan & Light Switch Wiring


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12 replies to this topic

#1 bnicholson

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Posted 19 November 2008 - 04:37 PM

Hi All,

My Client wants a switch on the wall for their ensuite bathroom to turn on the light and the fan c/w timer.

My concern is that I believe that a Fan needs to be able to be isolated but a pull cord scenario only turns off the power to the light and the fan until the timer runs out.

Do I need a separate isolator for the fan and what type of switch / wiring arrangement will I require please?

Many Thanks

Bob


Appreciate how this can be achieve please.

#2 Apache

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Posted 19 November 2008 - 05:13 PM

AFAIK you do need isolation for the fan. What if it developed a fault? Pee in the dark?

You want a 3 pole fan isolator switch

Often mounted outside of the en-suit often on the ceiling or en-suit wall

:)

#3 Evans Electric

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Posted 19 November 2008 - 05:20 PM

The Noble Redman is right, that will do the job. Another method is fit a spur in the lighting feed , the thinking is that the light and fan are now linked by the trigger wire and the spur isolates both .

#4 DYCHE4230

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Posted 19 November 2008 - 05:21 PM

Hi

Yes you'll need a triple pole isolator if the fan has an overrun timer.

the wiring arrangement will depend on your existing, but basically the fan and light will require the same switched live and the fan will also need a permanent live. the s/live, live and neutral to the fan will obviously need to pass thru the isolator.

I'm assuming you will be putting the switch outside the ensuite?:^O

regards

#5 bnicholson

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Posted 19 November 2008 - 05:47 PM

I thought Apache had the best answer - who wants to pee in the dark if the fan develops a fault!

Thanks for the response.

Bob

#6 batty

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Posted 19 November 2008 - 08:50 PM

As far as I know a fuse/mcb is classed as an isolator for a fan. But all the fans I have fitted ie that I have wired I put an isolation switch in circuit. Either 3 pole switch outside room or ashley 3 pole pullswitch. It give customer option of having fan off if they don't want it on and also for maintanance purposes. Although today I changed two noisy fans on a job. They did not have isolation switches but I did not install them in the first place.
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#7 SPECIAL LOCATION

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Posted 21 November 2008 - 01:24 AM

3-pole switch can be INSIDE the room if in an appropriate zone!;):)

#8 avinalarf

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Posted 23 November 2008 - 09:48 PM

Hi

Yes you'll need a triple pole isolator if the fan has an overrun timer.

the wiring arrangement will depend on your existing, but basically the fan and light will require the same switched live and the fan will also need a permanent live. the s/live, live and neutral to the fan will obviously need to pass thru the isolator.

I'm assuming you will be putting the switch outside the ensuite?:^O

regards

Does this mean a triple pole is NOT required if your fan doesn't have an overrun facility?

#9 Apache

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Posted 23 November 2008 - 09:49 PM

Does this mean a triple pole is NOT required if your fan doesn't have an overrun facility?


Suppose strictly, BUT
  • Not a bad plan being able to isolate fan
  • Over-run is useful to clear steam and odours!


#10 Mr Sworld

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Posted 23 November 2008 - 11:27 PM

If the fan doesn't have an over-run facility it probable won't have the 'switch live' terminal that allows it to be triggered from the light. Hence only live and neutral will be present so only a double pole isolator is required.

#11 MalcyB

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Posted 27 January 2009 - 12:29 PM

Hi Sorry to bring this post up again, but I have never installed an extractor with a run on timer. So I just want to get things clear in my head.

I would be bringing a feed (L/N) from a ceiling rose to an FCU. We have a triple pole isolator to switch the fan on & off, so the L, S/L & N would go through there, but if the fan is to run on the L would need to be permanent, but if it's going through the isolator when it's switched off it would cut the power. Forgive my ignorance but this really is a new one on me.

Malc

#12 Subneural

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Posted 27 January 2009 - 03:54 PM

You bring the perm live, neutral and switched live from the light through the triple pole isolator to the fan. The fan then switches on with the light and off automatically a set time after the light is swictched off. The isolator is intended to remove all power from the fan for maintenance purposes.

#13 MalcyB

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Posted 27 January 2009 - 04:16 PM

We don't want the fan to come on with the light, we want it to come on from a pull switch. The FCU will be the isolator in this case then, so I suppose I'll be using the fan isolator pull switch just as a switch, with the S/L coming from a junction box, back to the box then 3core to the fan? Thing is the fan isolator pull switch won' be an isolator!!?
Malc




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