3 way switch wiring...stuck

aliasojo

When I took down the old stud wall, I took off the old light switch and carefully noted down what wire went where. Can I find the notebook now? Nope!

So I have a 3 way switch.

1 cable with red / black / neutral comes from bathroom ceiling light
1 cable with red / black / neutral comes from the hall landing light
1 cable with red / black comes from bathroom extractor fan
1 cable with grey / brown / black / neutral comes from another switch.

I think 2 of these cables were wired together but don't ask me which ones.


Can someone tell me what goes where please? (Please no warnings about electricity and professionals, I appreciate the concern but it's not helpful to me.)

I've googled but I'm getting confused with the terms used......I need someone to tell me very simply .......put the bathroom red wire into L1 of the first switch etc etc.

Meepster

I could tell you, but then I would feel VERY guilty if you ended up blowing yourself up!

So if you don't know what you are doing, get a professional in. Please. For the sake of your family...

And yes, i did read the bit saying you don't want any warnings etc. But tough...

aliasojo

The worst that will happen is that the main consumer unit rcd will trip.

ormus

http://www.ultimatehandyman.co.uk/three_way_lighting.htm

esuhl

I did the same thing a few years ago, and couldn't find a wiring diagram anywhere... except in a 1960s hardware manual!

I can't remember which wires went where, but I recall that the terminals were labelled earth, live, neutral and switch.

Is it anything like the diagram on this page (scroll down a bit):
http://www.diydoctor.org.uk/projects/lights_and_switches.htm

aliasojo

Ok...it's not a 3 way switch...it's a 3 gang switch. I was searching using the wrong term.

aliasojo

Can't find a diagram, c'mon guys, help me.

aliasojo

Never mind, it's sorted now. Lights are up and running.

Electrician is coming down to wire up new shower and main light so I'll get him to check my work whilst he's at it.

I wouldn't take stupid risks, I'm a very capable sort who just needs a few pointers but I can appreciate people's reluctance to offer advice on something like this.

zax47

Firstly, your cables are red/black/EARTH (either bare copper or green/yellow sheathed), not red/black/neutral!

Secondly, you have both old and new cable colours - Red (live) and Black (neutral) were replaced by Brown (live) and Blue (neutral). For 3 core (2 way switching) cables, Red, Yellow and Blue were replaced by Brown, Grey and Black.

Earths all go to the earth terminal on the back box and, if they are bare copper, must be sheathed using green/yellow earth sheathing.

Your cable from hall/landing light is part of a two way switch which also uses the grey/brown/black cable going to the other switch, to enable two-way switching.

For the cables EXCEPT THE HALL/LANDING ONE put red in common and black in L1 (or L2 - it doesn't matter). If the switch rocker is the wrong way up then swap the black from L1 to L2 (or vice-versa). The black wires should have either a piece of red sheath or red tape on them to denote their potential live status (they will be live when the switch is on)

Then -for the hall/landing light ONLY - firstly, put red in L1 and black in L2, then take the other switch off and see where grey, black & brown are located - there is a convention to be followed, but not everyone does! Put your grey/black/brown in the same locations on your switch. As long as you put the same colours in the same places on your switch then that's fine but DO NOT MIX THEM UP. See here for more;

Two-way lighting switch wiring

The diagram there is very useful!

This means, for the hall/landing switch you will have 1 wire in Common (probably Grey) and two wires in L1 and L2 (red and one of the two way cables, and black and the other 2 away cable.) DO NOT MIX THE BLACKS UP - the black associated with the red must not be connected to it!! The grey and black cables should all have either a piece of brown sheath or brown tape on them to denote their potential live status.

Don't forget to turn the power off before working on this!

For the benefit of my PLI insurers, what I give above is purely ADVICE and in a non-professional capacity. The reader follows it at his own risk -I accept no liability for it being correct, despite being a professional electrician!!

ormus

aliasojo wrote: »

Ok...it's not a 3 way switch...it's a 3 gang switch. I was searching using the wrong term.

a 3 gang switch (or socket) is just 3 x single switches in one unit.
ie

aliasojo

Cheers zax...where were you a while ago? You could save saved me an hour of my time spent googling.

I must try harder to stop the bad habit I have of calling the earth wire neutral......I know exactly what I mean but it does confuse the issue and makes people think I'm clueless when I'm really not.

I had done exactly as you said (I went back to check step by step whilst reading your post). Only thing I haven't done is to use tape to denote live but the wire has been marked and I'll get some tomorrow and go back and do it.

Thanks for taking the time, it's good to have confirmation that I've done the right thing.