Replacing a 3 Gang Switch for Upstairs Landing but Cannot Figure out Wiring

by **ollieonline** » Sat Jul 29, 2017 5:25 pm

I am hoping that one of you wonderful people will be able to help me.

I am trying to replace a three gang light switch in my hall way. The switch operates the upstairs landing light (which also has a switch up stairs), the porch light and the hall way light - both of these last two switches are only controlled from this switch - i.e. there are no others.

The existing switch has:

Top Row - L3 (empty) / L2 connected / L1 connected / L3 empty / L2 connected
Bottom Row - L1 connected to the cable in the wall and also to the other L1
on this row /L3 connected / L2 connected / L1 connected

The new switch has Top Row L1 / L2 / Com / L1 / L2
Bottom Com / L1 / L2 / COM

(I've attached some pictures to hopefully make things clearer - the switch with the black back connectors is the new one.)

I am at a complete loss of how to wire this up. I've tried a few things and i cannot seem to get all the lights working, so far the best I have had is two of them working and the worst - none of them working - where am I going wrong?

by **Mr White** » Sat Jul 29, 2017 7:35 pm

You should connect it as it was before. Its just the same switch but different names.

L1 is now Com
L2 Is now L1
L3 is now L2

by **ericmark** » Sun Jul 30, 2017 12:54 am

I can see a sleeved blue and yellow wire going to different switches that does not seem correct. I would expect to see the cable with red, yellow, blue to go to one switch, That cable would be for the two way light.

As said already
Com = L1
L1 = L2
L2 = L3

by **ollieonline** » Sun Jul 30, 2017 5:23 pm

Thanks both for your help.

Wiring it up the way you both said works, i can't believe i missed that, its obvious when you said it! but I'm not a sparky.

ericmark - i didn't have to make any changes to the other wires.

by **kbrownie** » Mon Jul 31, 2017 4:35 pm

One other thing that you should be made aware.
Metallic switch plates require to be earthed, you have a number of CPCs connected to the back box, you need confirm they are offering a fault path to earth, there visual existence is not enough. Once confirmed they then not to be terminated to the switch plate.