Replacing 2 gang light switch

Edwardpoint · 2026-01-10T07:41:22+0000

Hi everyone,

I've just moved into a new build flat & I want to change the light switches to smart switches. I've bought one just to try it out.

I've changed light switches before at my parents home, but the wiring on this switch has me a bit confused as to what to do.

The old switch has brown wires going into each COM, brown wires going into each L1 with another wire going between both L1s.

The new switch only has L, L1 & L2. Assuming the two wires going into COM need to go into the L1,L2 of the new switch, would I need to use a wago to connect the two wires going into the L1s of the old switch to go into the L of the new switch?

I've attached pictures below for reference.

Thanks!

img_b68bea69-1644-4bb5-8559-b4c2ed130633-jpeg.404162

mikeyd · 2026-01-10T08:58:03+0000

Try putting both of the wires that went into the L1's(old switch) into L(new switch) and each of the wires that were in COM(old switch) into L1 and L2 on the new switch. Hopefully you don't need a neutral.

jj4091 · 2026-01-10T09:55:44+0000

It looks to me as though there may be a need for a neutral as without one the load appears to need to be limited to 5 Watts, about the same as a single LED lamp. Op does not say what will be switched.

SUNRAY · 2026-01-10T10:26:52+0000

mikeyd said:
Try putting both of the wires that went into the L1's(old switch) into L(new switch) and each of the wires that were in COM(old switch) into L1 and L2 on the new switch. Hopefully you don't need a neutral.

There are loads of blue wires there too so I'll guess no problem to get a neutral.

Edwardpoint · 2026-01-10T13:57:40+0000

Thanks all! I've been able to get the switch to work with no issues! I'll look into getting one of the neutrals in as well. I'll need a deeper backbox to accommodate the new switch, I don't suppose any of you have had any experience with that? lol. Thanks again!

securespark · 2026-01-10T14:08:27+0000

Unless the wall is peculiarly shallow, you should be able to take out the existing dry lining box and replace it with a deeper one.

How deep is the switch from the back of the plate?

SUNRAY · 2026-01-10T15:15:15+0000

securespark said:
Unless the wall is peculiarly shallow, you should be able to take out the existing dry lining box and replace it with a deeper one.

How deep is the switch from the back of the plate?

It had never occured to me before that deepr PB boxes exist

securespark · 2026-01-10T15:30:02+0000

I've come across 35mm, 45mm and 47mm deep dry lining boxes.

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Replacing 2 gang light switch

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