Light Switch problem - urgent

[Steve Kn]

Hi,

It was all going smoothly until the decorator painted over my wiring diagram...

I have two lights in my lounge controlled independantly by two swicthes on a single plate (don't know the techical term, sorry)

I have two 4 core cables coming in behind the switch plate : red, blue, yellow and earth

There are two switches on the plate with connections on the back as below:

com com

1way 2way 1way 2way

Please help!

Thanks, in advance

Steve

 

[Spark123]

 

[Steve]

Firstly you need to determine which wire is perminantly live. Put all 3 live wires individually into pieces of terminal block, being carefull as to not leave any metal where it can be touched. Get a multimeter set to volts AC range and switch supply back on. Black lead lead to earth, red lead to each individual wire in turn, one should read approx 240v. Switch supply back off. This wire needs to conect to C on one gang and loop to C on the other with a short piece of wire. Put the other two into Gang 1 L1 and Gang 2 L1. Switch supply back on and should work. You may need to swop L1 - L2 over if switch operates upside down, remember to switch off before doing any work.

Did you even read the original post? he has 2 pieces of 3C+E coming into the switch.

steve, with that wiring setup, it sounds like you have 2-way switching, so there should be 2 more switches somewhere else for the same lights. If you find said switches, copy the wiring in these over to the problem one. If not, you have strange wiring.

 

[andy]

I have two 4 core cables coming in behind the switch plate : red, blue, yellow and earth

its 3C +E. youd know that if you read 'for reference'.

 

[Spark123]

oops.

 

[Adam_151]

One cable goes to each switch, i'd hazard a guess that red goes to com, and yellow and blue go to L1 and L2 (doesn't matter which way around), if this doesn't work try it with yellow in com instead of red, and if still no joy try blue there, oh and if the wrong switches work the wrong lights, you just have the wrong cable to each switch and just needs all the cores swapping over

Hope this is helpful,

Regards,

Adam

 

[Steve Kn]

Andrew - I didn't read the "for reference".

Crafty - I don't have switches elsewhere so I suspect I have strange wiring, which seems to be a feature around the house. Thanks anyway.

Spark - thanks anyway!

Adam - Thanks for the advice off to try it now.

Steve

 

[Steve]

Adam's advice wont work unless you have 2-way switching - switches somewhere else too.

best thing to do is either trace the wiring (see wiring diagrams for what to look for).

Another guess is the electrician had a reel of 3C+E that he wanted to use up before the next job, or he ran out of 2C+E, so red is live and either blue or yellow is switched live.

(Although i should take back what i said about Adam's comment, since his advice would work were this the case, but try either blue OR yellow in L1 first, then swap them if it doesnt work otherwise you will permenantly have a loose wire that is live in a junction box somewhere whenever your light is off)

 

[Steve Kn]

All fixed now guys - many thanks for your help.

For your info I wired the red into the two commons (with a link between the two). The two yellows into each one-way and then I linked the blues together. It turns out the rest of the lighting in the house wouldn't work otherwise. I suddenly had a flashback to the original wiring.

Thanks again for your quick responses. I won't hesitate to come back if I need more help.