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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Electrical Questions >> Help changing a light switch https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1314882320 Message started by mcol on Sep 1^st, 2011, 2:05pm

Title: Help changing a light switch
Post by mcol on Sep 1^st, 2011, 2:05pm

I'm trying to replace a double light switch in my living room that has two light fittings on the ceiling.

Coming in are 1 live, 1 earth and two other wires (presumablu switch wires).

I'm using a 10amp double 2 way switch and have split the live wire to produce two feeds, which I've connevted to the two com terminals. The two other wires are connected to the two L1 terminals.

All works, except that the secomd light only functiomd when the first light is switched on.

Any advice would be much appreciated!

Title: Re: Help changing a light switch
Post by CWatters on Sep 1^st, 2011, 4:47pm

Some questions..

Is this new behavior? eg did it work properly before?

Were there two switches originally (one per light) or one switch working both lights?

Is there another switch elsewhere in the room that also worked the lights?

What colour are the wires and were any marked/sleeved with a different colour band?

Title: Re: Help changing a light switch
Post by mcol on Sep 1^st, 2011, 5:00pm

Thanks for the interest here;s the answers to your questions.

It's new behaviour, I'm just trying to replace an old 70's style switch which was wired as black to com, both red wires to the l2 connections and a "patch cable" going from the first com to the other.

Just one switch used to work both lights.

There are no other switches involved.

The live wire is black and the other two are red with no markings at all.

I've tried every cobination on the switch and can only assume the new switch is the wrong type.

Regards, Mick

Title: Re: Help changing a light switch
Post by scotspark on Sep 1^st, 2011, 7:44pm

do you have a voltage proving device such as a multi meter or even a neon screwdriver :'(

the wire you think is the switch wire for light 1 is the wire you have used as the live feed and that is why you need light 1 on to sw on light 2

if you swap them over you should be fine

Title: Re: Help changing a light switch
Post by mcol on Sep 1^st, 2011, 8:03pm

Thanks - that makes sense.

Title: Re: Help changing a light switch
Post by CWatters on Sep 2^nd, 2011, 9:06am

I agree.