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in-line fan in bathroom ceiling

Postby eddie » Mon Sep 24, 2007 5:46 pm

Her we go

I've been looking at installing an in-line fan in the loft above my new shower room. The intake vent will be in the cubicle the exhaust in the soffit conected by 'elephant trunk'

The fan is to be connected to a switch outside the bathroom so that when the light comes on the fan comes on, then runs for 5 mins or so after the light has been switched off.

Looking at the instructions it implies that the power source L & N from another light has to go through a double pole switched fuse spur at 3amps, mounted outside of the shower room then to the ceiling rose light, light switch ,fan.

This would then have me having 2 switches outside the room 1 a light switch the other a switch f/spur is this right?

reading other posts on other sites this f/spur system is for the protection of the fan motor therefore as I believe:

1. I could wire it this way but put the F/spur in the loft next to the fan

2. I could split the ring main, as its just outside my shower room, add a f/spur and take the light and fan circuit off the ring main, which would then mean they were protected by a 30mA RCD.

3. I also believe that none of this is necessarry and that my incoming supply from previous light would go into shower room ceilng rose, then I could run a 3 core & E from there to a 3 pole switch mounted outside of the shower room and a 3 core & E from ceiling rose to the fan in the loft, connecting it all up in the rose.

Can someone who has any knowledge of this assist please. I've looked in regs and can't find a thing relating to this
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Simply Build It

Postby Andy F » Tue Sep 25, 2007 8:08 pm

Eddie, we're just getting this done and it's going via a F/spur in the loft next to the fan. Hope this helps.
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Postby sparx » Tue Sep 25, 2007 9:05 pm

Hi Eddie, regs don't require any other sw. you can simply run 3core & earth of which the E will be unused at fan end but must be connected at light end to comply! run from ceiling fitting which has Perm L , sw, L & N.
only reason for having a 3 pole fan sw in the line is if room has no natural light so at service time if light cct. is killed at mains then you would be working in the dark, so by putting fan isolator in line you can work on dead fan with light on, however as you're fitting duct fan in loft then this does not apply anyway, so no isolator/FCU is reqd. FCU[Fused spur] is no use at all because you have 2 live conductors plus N to isolate with a timer overun type of fan. regards SPARX
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Postby rosebery » Fri Sep 28, 2007 11:19 pm

Hey Sparx make your mind up. Only just recently you've told someone else it's ILLEGAL under Part P to do outside electrics themselves but here you are encouraging someone (by telling them what to do) who you don't know is Part P or not to do ILLEGAL (by your definition) work if they are not so qualified in an inside special location.

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Postby sparx » Sat Sep 29, 2007 8:27 pm

Hi newby-rosebery,
First, yes I do advise most people abt Part-p however apart from the sheer boredom of it I also make a personal judgement on the questioner,
some peoples obvious lack of any knowledge leads me to try to 'frighten them off' as they are patently dangerous; however some show that they have tried to do it correctly ie looked in the regs etc. In the above case for instance 'eddie' is using correct terminology, and logical thinking & is no doubt going to do it whatever is said and it is in his loft so not in bathroom, once connected .
I rightly or wrongly take the view that a little guidance is all thats required, & it's better that than none at all.
It would be far easier to do as some others do & just keep trotting out 'Not DIY' 'Part-P' forum might as well just consist of a blanket statement not to touch anything electrical, I WISH!!!!
I have found incidently some posts on here from registered 'part-p' leckies asking about a situation they have not met before, they don't always own up at first so you can easily be 'preaching to the converted'
This is the best non-trade-only forum about so lets not start 'snipeing' and reduce it to the level of the screwfix one!
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