Light switch help

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RogPJ

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I hope that someone can help with a light switch problem. There is a single light switch which controls the lounge lights and it’s wired like this: [GALLERY=media, 106059]C6990933-7979-4260-AEBF-C94C165FB7D8 by RogPJ posted 14 Feb 2021 at 12:40 PM[/GALLERY]

Then there is a double light switch which also controls the lounge lights and the conservatory lights, which is wired like this:
[GALLERY=media, 106060]B96751C7-5D40-4BD0-9BFE-215C7B409BF8 by RogPJ posted 14 Feb 2021 at 12:40 PM[/GALLERY]

When I replaced the old lights switches everything worked as it should and now nothing works! Hopefully the photos are clear enough to help someone tell me which cable should go where. Thanks!
 
Each two way switch has three terminals, com, L1, L2, there must always be a wire in com and in one picture there is no wire in com.

Two way switches have line in to Lx and line out to Lx and a wires joins all the terminals on one switch to the other, as long as the com wire goes to com on other switch which way around L1 and L2 are does not matter.

Used as a on/off switch either L1 or L2 is not used, so line in to Com and line out to Lx. Swapping L1 and L2 swaps if switch up or down for on.
 
For start there is nothing connected to the com terminal in the two gang switch ( bottom pic)
Did you take pics of wiring at original switches ?
 
terryplumb said:
For start there is nothing connected to the com terminal in the two gang switch ( bottom pic)
Did you take pics of wiring at original switches ?
Click to expand...
Rather stupidly I didn’t take any photos as I’d already done the other light switches in the house by just copying the connections to the new light switch. I’ve tried connecting wires to both of the com wires (in the original switch they were twisted together and only in one of the com connections), but that didn’t work.
 
Have a look at the outer sheaths that come into the two gang switch position ,there appears to be three,is that correct ?
One sheath has a red ,a blue ,and a yellow insulated conductors ( and of course an earth ,which we can ignore for clarity ). Those should all connect to one gang ,it's red in common ,(the other two in L2 and L 1. As they are in your pic)
That leaves 3 more red conductors . Have a look at the sheaths that they originate from ,and tell us what other colours are in each. Does one sheath have two red conductors coming from it ?
 
terryplumb said:
Have a look at the outer sheaths that come into the two gang switch position ,there appears to be three,is that correct ?
One sheath has a red ,a blue ,and a yellow insulated conductors ( and of course an earth ,which we can ignore for clarity ). Those should all connect to one gang ,it's red in common ,(the other two in L2 and L 1. As they are in your pic)
That leaves 3 more red conductors . Have a look at the sheaths that they originate from ,and tell us what other colours are in each. Does one sheath have two red conductors coming from it ?
Click to expand...
Thanks for your help, I’ve connected up the yellow, blue and red wires as you mentioned and now have 3 red wires not connected. All three of them come from sheaths with black and earth cables. The black cables are all connected together in a connector block.
 

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One should be permanently live ,irrespective of the switch position of the single gang switch ,establish which one ,and put it into com on the switch that is one way ( so not the switch with the three core).
Connect anyone of the other two loose reds into L1 of the one way switch . Leave the third isolated at present and advise the results .
 
terryplumb said:
One should be permanently live ,irrespective of the switch position of the single gang switch ,establish which one ,and put it into com on the switch that is one way ( so not the switch with the three core).
Connect anyone of the other two loose reds into L1 of the one way switch . Leave the third isolated at present and advise the results .
Click to expand...
Yay we’re nearly there! Lights work as they should apart from the dining room lights don’t work, but that’s because I have 1 disconnected red cable. Where should this be connected? I am assuming one of the com?
 
RogPJ said:
One of them is live, the other 2 are not
Click to expand...
And did you do this?
terryplumb said:
One should be permanently live ,irrespective of the switch position of the single gang switch ,establish which one ,and put it into com on the switch that is one way ( so not the switch with the three core).
Connect anyone of the other two loose reds into L1 of the one way switch . Leave the third isolated at present and advise the results.
Click to expand...
 
So your conservatory lights work ok?
Go to the other switch position ( single switch) and tell us what voltages at com, L2 And L1
 
Thank you so much! With your help it’s now all working and my wife is happy :)
 
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