Light Switch Replacement - 2 Gang 2 Way.. A Little confusion!

ChilliBob

Hey guys,

I've successfully replaced a number of one way one gang light switches this morning, however, a two gang two way replacement has me flummoxed.

Essentially my new switch looks like this:


And my existing wiring looks like this:



So here we have a 'top' section with
L1, L2 and Common........ Just L2 and Common have a cable in. 

Then we have a bottom section
Common, L1, L2... Here all options have a cable in them. 

My best guess is that:
* Old switch controls the lights with a row at the top and a row at the bottom for each one
* New switch controls the lights with a column on the left and one on the right, for each light.. 

So, perhaps

Existing top row:  L2 goes to L22 on new switch, common goes to Com 2
Existing bottom row: L2 goes to L12, L1 goes to L11 and Common goes to Comm 1

I'm not too bothered if the new two gang controls the lights using different rockers to before - Ironically they're hardly ever used! - Cabinet lights for one rocker, and hall lights for another (which we control via a Hue sensor so don't use the switch!).

The hall lights are the two way ones, so, I'm thinking in the current switch those are probably the bottom row - just because it's more complicated! The cabinet lights are just one way.

Oh and I know where the earth wire goes, that's disconnected for this picture as I was about to replace before much head scratching commenced and I thought better of it for a while!

Any help much appreciated - this is the last one for me to replace before I can do a bit of filling and re-decoration! 

Section62

ChilliBob said:

So here we have a 'top' section with
L1, L2 and Common........ Just L2 and Common have a cable in. 

Then we have a bottom section
Common, L1, L2... Here all options have a cable in them. 

My best guess is that:
* Old switch controls the lights with a row at the top and a row at the bottom for each one
* New switch controls the lights with a column on the left and one on the right, for each light.. 

Guessing with electrics is dangerous...

In both cases the split is a left side and a right side, associated with each rocker on the front of the plate.

ChilliBob

Section62 said:

ChilliBob said:

So here we have a 'top' section with
L1, L2 and Common........ Just L2 and Common have a cable in. 

Then we have a bottom section
Common, L1, L2... Here all options have a cable in them. 

My best guess is that:
* Old switch controls the lights with a row at the top and a row at the bottom for each one
* New switch controls the lights with a column on the left and one on the right, for each light.. 

Guessing with electrics is dangerous...

In both cases the split is a left side and a right side, associated with each rocker on the front of the plate.

Indeed dangerous! Hence why I decided to leave it until a guess felt more like 'highly certain'!... 

So you're saying on the existing light switch that L1 and L2 on the 'top row' go with Common on the bottom left, and that Common on the top right is grouped with L1 and L1 on the 'bottom row?

Is that what the circle with the two slightly diagonal lines from it is indicating?

ThisIsWeird

Two separate switches on each plate, as said by S62. Split diagonally - indicated by the triangles on each plate.

Annoyingly, they are upside-down in relation to each other, but that's as far as the trickery goes - it should still make sense.

Just keep the two switch sides - triangles - separate. Transfer the wires from the one plate to the other, one switch at a time.

Move the 'COM' from the first switch to the new one. Then move the associated '1' and '2' to ditto.

Then repeat for the other switch.

Nod to show you understand. Do not proceed unless you nod.

ChilliBob

Thanks, I was just sbout to do a drawing like that to see if I had understood correctly! That's really helpful, thanks.

I'll do what i did on the others before - masking tape on the cable with a written L1, 2, comm so I know what I'm doing! - but with a extra marker for each side, perhaps green and blue pen he he. 

ChilliBob

Well with an empty house, some masking tape, and a slow and methodical approach I've sorted it

Took your advice of one switch at a time migration, which given the position of the wires I thought it could be tricky, but worked out okay. Can crack on with the decorating now!

Thanks both