Extractor fan and loft switches

**1ManRiot** · 31-07-2011

From another (non electrical) forum, someone has posted a thread about changing a knackered pull-cord switch in the bathroom that he cannot seem to get working.

As an apprentice electrician I've been trying to get my head around it and I can't quite figure it out, especially without seeing it for myself. Is there enough info here to diagnose?!

Thanks

Originally Posted by uihhhlhuhuhuh

Hmmmmm my setup is seperate from the light and it did work prior to the switch breaking and having to change it. I cant work out why it no longer works and seems to be turning on when a switch for the light in the loft is turned on???

I have pics now to explain my setup better.

As you can see on pic 1 the grey cable on the right is taking power into the socket in the loft. You can also see the wires between the small gap between the socket and light switch. This is the source of power to the light switch in the loft which causes the fan to work when the pullcord downstairs is in the on position. This is the only place this light is connected to the circuit. Grey cable outta the socket takes power to the brown box and feeds into the fan circuit

Close up of the brown box taking power to the fan circuit. Power to the fan circuit comes off the top grey cable. The other grey cable takes power to another thing in the loft. Not sure what for.

Cable then passes through this box. The light is on and it is getting power.

The cable then travels to this box (top grey cable on right). The cable on the left travels to the fan. The bottom grey cable on the right goes to the pullcord switch.

This is the pullcord switch. I have wired it in every possible combo to get it to work lol. This is just how I left it last night when I got fed up messing. When in the on position the light is on so it is getting power.

Why the **** would the light switch in the loft affect this? Why wont it work? HELPPP!!!

**truckster** · 31-07-2011

Prime example of why non sparks should leave well alone. And this is in a bathroom?

**alli** · 31-07-2011

Hard to tell, could someone,@*! of taken a live from the socket into the common of the switch, then from the other side of the switch back to the double socket the same as a switch live. Which connects to the cable going to the fan unit. This would then only allow the fan to operate if the loft light was in the on position.This is assuming the loft lighting has a neutral by either three core or they've used the cpc! I would like to look behind the double socket and the loft light switch to see how this is wired because if the loft lighting switch and light fitting are not joined to anything else then there is no way it can control the fan.

**Guest123** · 31-07-2011

Unsleeved CPC used as some kind of S/W.....the whole thing spurred off a socket outlet.....not even going to bother trying to help here.

**JOEKAIN** · 31-07-2011

that installation is a ******* disgrace you get what you pay for taht must have cost pennies what a unsafe shambles they should be reported

**Archy Styrigg** · 31-07-2011

Originally Posted by Lenny

.....not even going to bother trying to help here.

My brain's starting to fry just by starting how to work this out...no more!

To the OP, if you're an apprentice, don't bother trying to work it out, it'll just put bad ideas in your head.

I reckon if they stopped selling junction boxes to the general public it might slow your typical DIYer down, they seem to love them!

**electromonkey** · 31-07-2011

They should make this an exam question "List everything that is incorrect". I've lost count of how many things are wrong here.

The audacity of someone to post this to ask for help is amazing!! What forum is it from 1manriot?

The reason it's not working is fairly obvious. Have you worked it out yet? If you have don't let the OP know.

**1ManRiot** · 31-07-2011

Post comes from a general forum on a completely non-electric subject. It was merely a chap who's pull-switch had broken, so went to B&Q and got another one in the hope of swapping like for like. The electrics, shocking as they are, have probably been there for years. I have no involvement other than trying to work it out for my own interest; it's not anybody I know and I'm not planning to go round and correct it!!

**1ManRiot** · 31-07-2011

Originally Posted by electromonkey

The reason it's not working is fairly obvious. Have you worked it out yet?

No. I'm bored of looking at it now, I can't quite tell what is going on (and I'm over-looking at the pull-switch wiring as he stipulates he's already tried each combination).

It's something to do with the neutral (assuming the black is neutral LOL) in this:
photo1im.jpg

**beaver74** · 31-07-2011

can you post a link to the website as we may be able to see some thing from their posts

**Sparky_FM** · 31-07-2011

to me it seems that the new pullcord is double pole and he has the line into the feed side and the neutral (switch return) on the load side but on 2 opposite terminals which are not connected when switched so therefore the "switch return" will never get a live feed.

the setup is terrible and also the light in loft has not been fused down (if required anyway) the FCU is probably his way of fusing down the fan as per some manufacturers instructions

just a thought, if that makes sense

**vincentmcconnel** · 31-07-2011

danger written all over it....

**1ManRiot** · 31-07-2011

Originally Posted by beaver74

can you post a link to the website as we may be able to see some thing from their posts

I was reluctant to but I don't suppose it matters really does it?!
Bathroom extractor fan probs........

Originally Posted by Sparky_FM

to me it seems that the new pullcord is double pole and he has the line into the feed side and the neutral (switch return) on the load side but on 2 opposite terminals which are not connected when switched so therefore the "switch return" will never get a live feed.

the setup is terrible and also the light in loft has not been fused down (if required anyway) the FCU is probably his way of fusing down the fan as per some manufacturers instructions

just a thought, if that makes sense

I think you're bang on looking at some of the responses in the thread!