Double lightswitch, one switch return cable Ask questions and find answers to many subjects relating to electrics and electrical work

[Myrtle]

Hi. I am installing a light fitting in my dining room which is attached to a double switch. One switch operates the dining room light and the other the lounge light. When I replaced the lounge light there was just one live switched cable in the ceiling rose and no problem arose. When I came to replace the dining room light there were two yellow cables joined together in a separate terminal block of their own. When I connected my flex live to both of these yellow cables in the new terminal block, only one light switch worked but operated both lights together. Inside the double switch there is only one yellow cable. How do I get the two switches to act independently again? The inside of the switch says 1 way inside. On the top row there are L1 L3 and L2 connections. L1 has a red cable attached and has been pencilled over with R2. The L2 has a single yellow cable and has been pencilled over with Y. On the botton row I have L3 L2 and L1. L3 has a single blue cable to it (pencilled B) and L1 has a red cable (pencilled R1).

[ericmark]

As soon as I read two yellow wires connected together I thought intermediate switch. I have tried to work out what you have but sorry can't work out what you are talking about. A long time ago to help someone else I did a web page https://www.ericmark.talktalk.net/twoway.html if you look at bottom of the page it shows both two way and intermediate wiring diagrams maybe that will help you understand what you are looking at.
Eric

[Myrtle]

I have now managed to identify which cable in the ceiling has the switched live and therefore which yellow that is. The lightswitch itself, I actually slightly misread because it's dark! There is the one red cable that comes in to position L1 on the top and then the second red joins L1 on the top to L1 on the bottom (i.e joins the two switches together so that just the one whole 4 core cable comes into the lightswitch with everything else having been connected via the ceiling rose). This just leaves me with the spare yellow in the ceiling which I think is possibly reduntant. I am trying out all the combinations with a meter. My house has been knocked about over the years and was two flats at some point (hence two phone lines!) and so this switch may have been a 2 way at some point. It isn't any longer and I think there may have therefore been some creative wiring to confuse matters. Thanks though, I'm impressed with the speed of replies on the site.

[Myrtle]

It would appear that one switch wire goes from the 2 gang 1 way lightswitch to the dining room light. This was then connected to the switch wire for the living room light in a separate terminal block with everything else wired into the ceiling rose. The new light fitting is a 4 connection terminal block (i.e 4 pairs, sorry if I am using the wrong terminology)? In my working lounge light which is an identical new fitting, the terminal block was was wired up L, E N as normal and then the switched live to the flex live in the 4th connection. I now know that this switch live is attached to the lightswitch via the dining room switch wire. The lightswitch itself has a cross over live (red) wire from postion L1 on the top to the L1 on the bottom row. Does that make any more sense? I have now tried every combination I can think of and still can't get it to work.

[ericmark]

I think the only way to work out what you have is to draw it out. Looking at what you say I get https://www.ericmark.talktalk.net/temp.bmp what you need is to expand this as you learn more and then you will most likely see yourself where the error is. Trying to write out what you have is very hard but to draw is easy. Forget the earths in the drawing that only confuses things it is what I do. We are not suppose to use links on this forum I hope this one slips the net if not it is only what you have told me anyway.
Sorry can't be of much more help. You will note the loop wire the taking live to the rose first then to switch does seem to mess people up.
Eric

[Myrtle]

Thanks. I think perhaps a junction box is the answer and a professional electrician to sort it out. I think there has been some fudging in the past that I can't replicate.