Wiring 2 gang switch

[The Mekon]

I replaced a 2 gang switch in the hall. The marking on the back of the old switch were indisticnt, so I tried to match as best as possible.

On one gang I have black to COM and red to L1, works downstairs light, no problem.

The other gang has red to COM,  yellow to L1 and blue to L2.  If second gang switched off light upstairs won't operate, but will if switched on downstairs. I'm obviously missing something but not sure what?  

 

[Lurch]

Check the upstairs switch and match the colours/functions from there would probably be the best recovery option.

 

[Evans Electric]

Just what Lurchio said .....  it should work again if you note which colour is in the common upstairs and repeat it at the hall switch.

Edit :    The Mekon Eh !    Possibly a reader of The Eagle comic as a child  and fan of Dan Dare Pilot of the Future  Eh?

 

[Doc Hudson]

I replaced a 2 gang switch in the hall. The marking on the back of the old switch were indisticnt, so I tried to match as best as possible.

On one gang I have black to COM and red to L1, works downstairs light, no problem.

The other gang has red to COM,  yellow to L1 and blue to L2.  If second gang switched off light upstairs won't operate, but will if switched on downstairs. I'm obviously missing something but not sure what?  

If you have not touched the upstairs switch, and you have definitely got the correct wires allocated to each switch, i.e. the downstairs wires have not been crossed with the upstairs wires, then the COM for the upstairs light should not be the Red, it will need to be either the yellow or the blue. You will need to try swapping Blue-Red or Yellow-Red to see which way works.  You only have three wires and only one goes to the COM. You know its not Red, there are only two other options. This sort of problem can arise due to the way some manufactures label their switch terminals, some are called 'COM', 'L1', 'L2' another may be called, 'L1', 'L2', 'L3'.  With these designations often 'COM'='L1', 'L1'='L2' and 'L2'='L3'. So if someone replacing a switch starts matching the L1's and L2's on then matches the COM & L3 the wrong wire will be on the COM and give the sort of symptoms you describe. 

Doc H.    

 

[The Mekon]

Many thanks all of you for your help.

Doc - turned out to be as easy as swapping the yellow & red. I think I was fixated with red being live.

E. E. - I used to look forward to Friday night when dad brought me The Eagle.