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Timed fan in bathroom

Postby staplake » Sat May 19, 2007 5:44 pm

I have a timed fan for the shower. Its only to come on when I pull the ceiling cord, and then stays on for 10 mins after I turn it off again. Its not linked to the lights in any way, -just the way we wanted it (long story!)

The electrician who put it in gave us a switch without any "on/off" indicator/LED.

The ammount of times the damn fan has been running and we couldn't remembered whether it was on or off, or come home to find it still running as we hadn't turned it off etc... started to really get annoying.

[b][u]what Ive done so far[/u][/b]

I bought a switch from B&Q with a light and red/white on-off indicator.

The supply cable is the usual 3 core brown/blue/earth
The fans cable is brown, grey, black and earth.

The 'old' switch has two terminals that were used, 'common L' and 'L1': the joint 'common L' terminal, into which two brown live wires went; the blue(supply) and grey(fan) were joined in a little plastic block. The black (fan) wire had a brown sleve put over it and was put into L1 terminal.

(earths all joined together as usual)

The new switch has a supply and demand Live and a supply and demand neutral.

I wired the two live brown, that had previously been connected, to the supply Live and the black (with brown sleeve) to the demand live.

The blue and grey I wired to the supply and demand neutral respectively.

The switch works fine, but the timer circuit does not. ie: turn on and its on...turn off and its timer run-out.

Presumably I have screwed up with the timer wire which I have put in the wrong place...

Can I ask where should it go?

(and I do know that I'm breaking the law -however the last registered electrician wired up the boiler wrongly -twice, and the last corgi registered plumber plumbed in the boiler back to front, and the lelectrician before that failed to notice the entire house was not earthed!! - I have a lot more faith in your collective wisdom and my common sense than our local tradesmen skill!)[u][b][/b][/u][b][code][/code][/b]
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Simply Build It

Postby sparx » Sat May 19, 2007 9:00 pm

Hi, yup, we got it wrong again dad!...sorry
look at fan wiring diagram or term markings, at switch the live in goes to C & so does fan wire marked as perm live (prog brown also.)
The neutral in (Blue) goes in term block with neutral from fan, (could be the black)
leaving the other wire (grey?) as switched live in to go into L1 of switch,
not forgetting to connect earths thro' as well of course! Regards, (proper )
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Postby staplake » Mon Jun 11, 2007 9:52 pm

Thanks son....but I'm still up the creek without an electric paddle.

I have poured over you words and they make sense on any other switch I have in the drawer, but not this blessed one!

It seems a weird wired set up....

The block on the back of the switch has four holes LIVE LOAD and LIVE SUPPLY and on the other side NEUTRAL LOAD and NEUTRAL SUPPLY.

On cable comes in with four strands,
(2)brown (live),
(3)grey (switched live??),
(4)a black one covered with a brown sleeve (perm live???)

The other cable has standard (a)live, (b)neutral and (c)earth.

I had (a)+(2) in the LIVE SUPPLY
I had (b) alone in NEUTRAL SUPPLY
I had (3) alone in NEUTRAL LOAD
I had (4) alone in LIVE LOAD

That means that the fan comes on with the switch, but goes off with it as well ie: wouldn't go off on the timer.

I know you are a genius and the most helpful soul on the net does this sound a weird switch B&Q have sold me??

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