two way light switch Ask questions and find answers to many subjects relating to electrics and electrical work

[andy Griff]

Hi, I have a switch located at the top and bottom of the stairs. The top has 2 cables of twin and earth. one of these comes from the light and is live and switch. the other runs to the switch down stairs. The question is how do i wire them so they both run the light?

[ericmark]

The only way to use twin and earth to connect two 2 way switches is to take a live from an adjoining switch.
This can only be done if both switches are from same supply.
And it can also cause radio interference.
My web page http://www.ericpalmer.fsnet.co.uk/Lighting.html does show how but I would not recommend using twin and earth and I would recommend using triple and earth more instructions on http://www.ericmark.talktalk.net/lights.htm and in projects on this forum.
Eric

[andy Griff]

Thanks Eric, looks like i'll be making a mess then.

[Zed2008]

Hi Ericmarc,

Please could you just expand a little on your "Andy Griff". I have a similar problem the previous owner has used twin and earth wires at both switches and there was a little wire that pinched the live from the adjoining switch. Both switches are part of 2 two way switches. Unfortunately i had to take em apart and now have forgot how to put back. So the situation is this: Both are now acting has one way switches at both ends i.e can switch on/off from downstairs and then upstairs but cannot switch on from down and off at upstairs.

The previous owner used the junction box type circuit and the junction boxes(2) are crammed.

Many thanks

[Zed2008]

Hi Ericmarc,

Please could you just expand a little on your "Andy Griff". I have a similar problem the previous owner has used twin and earth wires at both switches and there was a little wire that pinched the live from the adjoining switch. Both switches are part of 2 two way switches. Unfortunately i had to take em apart and now have forgot how to put back. So the situation is this: Both are now acting has one way switches at both ends i.e can switch on/off from downstairs and then upstairs but cannot switch on from down and off at upstairs.

The previous owner used the junction box type circuit and the junction boxes(2) are crammed.

Many thanks

[ericmark]

OK if you look at number 2 in http://upload.wikimedia.org/wikipedia/c ... tching.PNG you will see wire B connects live to L1 on both switches.
So if you take a live from an adjacent switch to L1 then you can do away with wire B. You need to know which of the two wires from the lamp are line loop. And both the light you are working on and adjacent light need to be from same fuse or MCB.
I have already given links to my web pages which have more on same subject.
Eric
PS I do not recommend this method there are problems which are expanded on with my web page.