Live & Dead Wires in Light Switch

The old and the new are both 2 gang switches so i wanna keep it that way, both separate.

Ill rewire it in the morning.

JH
 
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Your new multimeter- you need it set to measure AC voltage. Put a pic up of the front of it & we can tell you where to set the dial (and which holes the probes go into).

EDIT As earlier, if the 2 light fittings are on different circuits, that replacement switch may not work properly/could cause a hazard in the future.
 
Forget the meter for now. Eliminate the dimmers.
Take each pair of blue and brown wires and connect them together.

do the lights now work? If so, all you need to work out is how to connect you new switch. If the lights don’t work, there’s a fault somewhere to find first.
 
But on the new switch, there is only one L terminal and 2 X terminals.
So does it matter which wire of the 2 browns goes in the two X terminals?

Both are on the same circuit.

JH
 
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Follow @Taylortwocities post above- v wise call, it'll prove the lights work.
Your Q about the wires- if both lights are on the same circuit you only need one of the live cores connected to L. You will use your multimeter to determine which cores are live and which are load.
You may be able to use the 'spare' core as a neutral (with more work) but STOP RELYING ON CORE COLOURS FOR FUNCTION, YOU MUST TEST TO DETERMINE POWER AND LOAD
 
Ok I wired my old switch back up the right way and it’s all working.

this is how I have wired it:
Browns in X.
Blues in Live.

01CD0BCD-E4CB-4E1F-A3BA-B63DD007E408.jpeg
so it’s all working.

Now, the new switch has only one L terminal. What do I do?
 
You need to work out which is the live wire in each circuit and which is the load. Use your multi meter set on ac voltage , range 300V and touch the copper of each cable in turn (still in the switch with the lights turned off) with one probe and the earth with the other. Two of the cables should give a reading, the other two shouldn't. The two that do are the lives. The other two cables are the loads, make sure you keep them in the pairs they are wired in at present. You may find that the lives are different colours in each pair.

Is the new switch a 1 or 2 gang switch? If you want to switch the lights independently you need a 2gang switch. If you only have one L terminal, i suspect that your switch is a 1 gang. Post a photo of the front and back of the new switch if you're not sure.
 
Now, I blocked one of the live blue wires and I plugged the other into the live terminal.
Then I put each of the brown wires into their X terminals.
That just put one set of lights on permanently and didn’t allow me to switch anything off.

so then, I swapped the brown wires around and now, although the display lights on the switch itself come on, only one set of lights works (right side).

what am I doing wrong?

JH
 
One is first attempt and the other works but only one gang.
 

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I have a new Lightwave smart switch and they all use a single L terminal, even for 3 gang.
 
Is this the right setting?
 

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Ok I have put it in the right setting and I see that the two wires which I have stuck a small red tape on are the ones with the voltage while the other two are dead.

the problem remains as to how do I wire up the new switch with only one L terminal?
 
Read my last post. You only need 1 live in the L terminal, doesn't matter which. Make the spare one safe (bit of terminal block)
 

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