Replacing dimmer switch with new dimmer switch

b34mer23

Hi all,

Had an old dimmer switch in my apartment that was only ever capable of handling halogen bulbs (LEDs would never turn off). Recently it more or less gave up; turning on the switch, the lights would briefly & barely light up before turning off again a second later.

I'm looking to switch it out, so got a new switch from screwfix, this one.

Turned off the lights at the fusebox, and started taking the switch off and it's here I need a hand please!

There was a live (brown) wire going to the 'N/O' connection (have marked this one), 2 other brown wires AND a black wire going to the COMMON connection. Apartment building was built in 2004 so I imagine that covers the neutral being black and lives being brown.

First question, am I right in thinking having the 3 wires going to the COMMON isn't good? Didn't feel right. It's just a bedroom with no other light switch in the room.

Second question: my new switch has L1, COMMON (indicated with tilde~ & arrow symbol) and L2. Any advice on where the wires I have should go? Switch's datasheet says neutral to L1 and live to COMMON but this 3rd live has me stumped.

Thanks in advance.

ted1

switches have a live and a switched live. No neutrals.

i assume that they each of the grouped wires (switched live )goes to a separate bulb and the single wire is the live

if there’s an extractor fan in the bathroom one of the wires will probably feee that too

This is it

None of them are neutral. Replace it like for like with the 3 wires going to C/Common and the single brown wire into L1.

N/O is normally open, and N/C is normally closed in your photo.

The date sheet will show neutral to the light then switch wire from light to switch, and a feed to the switch.

Generally you'll have a live in, live out at a switch, which is likely the two brown going to Common, as for the black, hard to know where this is going. Could be a permanent live to a fan, shaving socket, attic light, etc.