wiring a 2 way 2 gang switch

[Hardwick]

I have tried to replace an old and broken 2 way 2 gang switch but it's all gone pear shaped and I�m in desperate need of help before I tear all my hair out completely. Basically this is the set up: There are lights at the top and bottom of my stairs, the 2 way 2 gang switch in question is at the bottom and at the top is a single gang 2 way switch that I haven't touched. The right gang downstairs operates the light at the top of the stairs as does the single gang switch upstairs. The left gang should then just operate the downstairs light. I copied the old wiring carefully when I took it out but somehow produced a confusing muddle where the upstairs switch only working the downstairs light, the left and right gangs seemed to be swapped around and one switch was working the toaster or something equally annoying. So, after about 2 hours faffing, I've now got the 2 way thing working fine - the upstairs light is now brilliantly turned on and off by the upstairs switch and the correct gang of the downstairs switch. Hurrah! The problem is that I simply cannot get the second gang downstairs to work the downstairs light. In spite of the fact this should be the easy bit! I've got the live into the com port and second wire into the L2 port, which is what every diagram and Q&A says to do. The very confusing thing is that I have 4 separate cables coming into this switch and all the diagrams only seem to have 2.... any help very, very gratefully received...

[Harley]

Try here http://www.diydoctor.org.uk/projects/lights_and_switches.htm

[Hardwick]

Thanks - but I tried there already. These are the diagrams that all have two cables max coming into the switch. I have 4. Also, I have a two way switch and a one way switch going into one 2 gang switch - which isn't on the diagrams at all.

[keltik]

any of your friends sparkys? but seriously have you checked the bulb?

[Hardwick]

Unfortunatley, no sparky friends. I have checked the bulb though (admittedly after about 2 hours) and it's fine. I know the live cable is also fine because the first time I did it the downstairs light was the only one I could get working - but from every bloody switch!! My next plan is to nail up the switch with hardboard and stick a lamp on the floor!

[Tweed]

From what you say, you have this setup; a twin red for the strappers up to the two-way switch upstairs, and a single red for the feed for this and a single red for the switch wire for the downstairs light, making four wires. I think you may have already done this but, take a small length of wire and connect it to the com terminal that you have the live connected, the other end goes into the other com terminal, and the downstairs switch wire goes to L1.

[Hardwick]

Right - thanks for the last suggestion, I hadn't bridged the com ports before and haveing given it a whirl I now have light downstairs...Brilliant. Unfortuantely, it's now all working from the wrong switch!! Basically, the right gang and the upstairs single gang now work both the upstairs and the downstairs light at the same time. I am counting this as a significant breakthrough (thanks again) - but it's still not ideal. Is it possible that I've some how killed the live into the left gang? P.S. I've also tried bridging the neutral L1 ports as instructed by the man who came to fix the tele - but it didn't work and he'd gone by then so I couldn't scream at him...

[Tweed]

I think you have one of the strappers mixed up with the feed. Try this; in the two-way switch downstairs, swap the cable connected to the com terminal (not the bridge, leave it in place) with the cable in either L1 or L2. If you have exactly the same problem as before, swap the other one instead, i.e. swap com with L1, if no good, swap com with L2.

[Hardwick]

T - thanks for persevering! Unfortunately, this hasn't worked either. It's all gone so tits-up I'm going to try and start again (as briefly as poss): 4 cables into a 2 gang 2 way switch called A, B, C and D. They are all earthed but only one has a black neutral wire. Current configuration: A. Red - into - Left gang Com A. Black - into - Right gang L1 B. Red - into - Left gang L2 C. Red - into - Right gang L2 D. Red - into - Right gang Com Bridging wire (currently not in use) This is definitely all arse up. The downstairs light does work with the left gang - but only provided the right combination of off/on with the right gang and the upstairs switch.

[Tweed]

You have more cables than I thought. So you have to find out where the red and black pair are going to. It's either the upstairs switch or the downstairs ceiling rose. If it's going to the ceiling rose, connect red to com and black to L1, for the downstairs light. I'm hoping you're left with a pair of reds coming from the same cable and a single red. If this is the case, wire the twin red to L1 and L2 and the single red to com for the upstairs light. Forget about the bridge. If the red and black pair go to the upstairs switch then wire them into L1 and L2 for the upstairs light and the twin red into com and L1 for the downstairs light.

[Hardwick]

Well, now you see that's what I thought. The black and red definitely seem to work the upstairs light - when I put them in L1 and L2 I can get that switch working fine. However, the other two red wires (lets say from cables C & D) will not get the downstairs light going, regardless of the combinations I try - com + L1, vice versa or using L2 - that just gives me no power at all on the downstairs light. How the hell can I have four seperate cables anyway? Where are they all coming from?!! I'm going to have to call in a sparky aren't I?

[Tweed]

Well, you may have to. When you get the upstairs working with the red and black pair in L1 & L2, what do you have in com? With the upstairs working like this, one of the remaining wires must be a switch wire for the downstairs light, and the one left is either redundant or a feed for the downstairs light. If it's redundant you have to get the feed from one of the wires from the 2-way switch. Sometimes, to keep the upstairs and downstairs on seperate circuits (which is generally a good idea) the two-way is wired slightly differently, where at one switch you have 5 wires (2 twin reds and a single red) and at the other you have 3 wires (twin red and single). This would be more common in newer installations. The advantage is that you have a feed at both switches. If this the case, you can get a feed for downstairs from L1 or L2 of the 2-way if you haven't got one already (see above). That's about all I know about 2-ways. I don't think I can help you any more without being there, so good luck.

[Hardwick]

I've been away so not tried this yet but I backing you to be bang on the money... I'll post again with the results some time tomorrow...

[winniepooh]

1. are you sure you have a common live at the source.go to your upstair switch seperate all the wires and establish your feed and your your 2way wires .now go 2 your downstair switch and re-peat the procces u can acomplish this by a simple conternuerty test ,it would be advisable 2 go 2 both ceiling roses 2 establish your swith cables and your feed ie:phase eutral.@ the rose the switch cable wil proberbly be black and red ,the black cable should be marked with redd as it is a switch cable and ultimatley will become live,follow these steps ,you will be alwright,<i>[Email address removed as per site policy. - AB Editor]</i>. my name is mike 17 years electrition, who could never spell lol , good luck.

[Hardwick]

Mike - thanks for your help. I've just started a new job and have been forced to live with the problem since you wrote - but I'm about to give it another crack. [Email address removed as per site policy. - AB Editor]... I think I may still need some more help!!