Bs3676 light switch wiring

[elgaz]

I am installing a dimming switch in my living room, but the existing switch (installed in 2005 when the house was built) and wiring isn't as I expected, seems a bit of freestyling has gone on, but I'm sure that's just my inexperience.

The room has two ceiling lights controlled by a single switch. The switch controls nothing else.

I have a two-way dimmer switch, and was expecting to simply move two wires from L1 and central terminal on the exiting switch to the corresponding terminals on the new switch.

The existing switch is BS3676 with three terminals labelled L1, L2 and L3. No terminal labelled "central".

There are brown wires going into L1 and L3. Nothing in L2, which is actually totally empty, so couldn't attach anything anyway.

Two blue wires don't touch the switch, they go into a plastic "joiner" presumably to form a circuit. The earth wire is fixed to the metal back plate.

All shown in photo.

Any advice on how to proceed will be very gratefully received.

 

[ETAF]

see here L1 and COM

Types of Lighting Switches

Different types and configurations of wall mounted light switches as used in the UK

flameport.com

whats on the Dimmer switch - C L1/L2 or ???

thats a 2 way switch - so L1 connects to L2 when the switch is in 1 direction (say ON)- turn it the other direction (say OFF) and L1 disconnects from L2 and connects to L3
hence with 1 way switching - one of the terminals is not used

 

[elgaz]

Thanks for responding. The dimmer is a LED dimmer with common, L1 and L2. ( photo attached)

Makes sense what you've explained. In my limited experience, I just expected to see a wire going into a terminal marked C or something.

Does this mean I can just move the two brown wires to L1 and L2 leaving the common empty, and leave the blue wires as they are?

 

[pete01]

Old sw/ dimmer.

L1 to ~

L3 to L1

Yes leave the blue wires as they are.

 

[elgaz]

Well, that's done. As expected, just me not understanding. I just expected the Common terminal to be indicated with a C or a symbol.

If I'd had remembered it was called "Common" and not "Central" as I mistakenly said earlier, maybe I'd have realised.

Anyway, it's really nice to have had your responses to help me get there. Thank you both!