Help needed for new 2 gang dimmer light switch

[laubi02]

hi all,

I've tried googling this but cant seem to find all the info I need.

Im trying to replace an existing 2 gang dimmer switch with a new one I bought.

The room has 2 wall lights (operated by one switch) and a ceiling light operated by the other (which does not work). I've installed a new ceiling light which hasnt solved the problem so im hoping a new wall switch will.

I cant wrap my head to why the existing connections are like this and how to rewire the new one.

All i know is that I can remove the extra eart wire as the new switch is plastic?

Another quesiotn I have is why the com terminal has no screw for me to fix the wire in. Is it needed then?

Ive attached photos of the existing wired unit as well as the new one I bought. Sorry, I just realised this is not the clearest so ive tried sketching it out.

 

[snowhead]

You don't need common on those switches.
The drawing on the back shows using L1 L2.
Substitute (new) L2 for (old) C on your drawing.

And you don't need the Earth on the new plastic switch, there's nowhere to put it.

 

[westward10]

As you look at your sketch which one operated the functioning wall lights, left or right.

 

[laubi02]

As you look at your sketch which one operated the functioning wall lights, left or right.

on the sketch, its the right. on the 1st photo (154150), its the left switch (if screwed to the wall)

 

[davesparks]

Did you remove that black wire or was it already loose when you opened the switch?

If it was already loose whne you opened the switch I suspect that is the reason your light doesn't work.
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Is the the ceiling light 2 way switched, or has it ever been in the past?

 

[laubi02]

Did you remove that black wire or was it already loose when you opened the switch?

If it was already loose whne you opened the switch I suspect that is the reason your light doesn't work.
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Is the the ceiling light 2 way switched, or has it ever been in the past?

the black wire was already loose when I opened it. if 2 way means that it can be controlled by another switch, then no. Just this switch (2 gang). I didnt know whether this black one being loose is the problem or is it loose for a reason and I should just remove it or connect to a connector block?

 

[davesparks]

the black wire was already loose when I opened it. if 2 way means that it can be controlled by another switch, then no. Just this switch (2 gang). I didnt know whether this black one being loose is the problem or is it loose for a reason and I should just remove it or connect to a connector block?

It looks like it has fallen out of a terminal, I can't imagine anyone leaving a stripped end of a conductor sticking out like that.

You need to investigate and test it to establish what it is doing and where it should be connected.

What cables are there at the light which doesn't work?

 

[laubi02]

It looks like it has fallen out of a terminal, I can't imagine anyone leaving a stripped end of a conductor sticking out like that.

You need to investigate and test it to establish what it is doing and where it should be connected.

What cables are there at the light which doesn't work?

on the ceiling light (one that doesnt work), its got a green (I assume earth), blue (neutral) and brown (live) - this is from memory but definitely 3 wires, one being earth.

 

[davesparks]

on the ceiling light (one that doesnt work), its got a green (I assume earth), blue (neutral) and brown (live) - this is from memory but definitely 3 wires, one being earth.

You've got a joint in the cables somewhere then, is there any sign of a joint box or connectors pushed into the ceiling above the light fitting?

 

[laubi02]

You've got a joint in the cables somewhere then, is there any sign of a joint box or connectors pushed into the ceiling above the light fitting?

not that I could see but it is very difficult to see much beyond the light fitting as everything is screwed to a steel bar enclosed by UPVC

 

[davesparks]

not that I could see but it is very difficult to see much beyond the light fitting as everything is screwed to a steel bar enclosed by UPVC

Ah, i take it this is in a conservatory then? In that case all bets are off and it does explain the particularly terrible electrical work in the pictures.

 

[laubi02]

Ah, i take it this is in a conservatory then? In that case all bets are off and it does explain the particularly terrible electrical work in the pictures.

oh no...didnt realise this made a difference. So does this mean that apart from dismatling everything (including the conservatory roof), my best bet is to trial and error?

This may be a dumb qestion but if I did do a trial and error with the switch wires, will it only trigger my main power fuse box and wont do any further dmaage to the lights and/or wiring?

 

[westward10]

No one is going to suggest trial and error. The safest option is to engage an electrician who can hopefully correctly trace everything.

 

[davesparks]

oh no...didnt realise this made a difference. So does this mean that apart from dismatling everything (including the conservatory roof), my best bet is to trial and error?

This may be a dumb qestion but if I did do a trial and error with the switch wires, will it only trigger my main power fuse box and wont do any further dmaage to the lights and/or wiring?

Your best bet is to get an electrician to investigate what is going on.

Trial and error does run a high risk of causing a fault which trips a circuit breaker or operates a fuse, and there is a chance of doing other damage. However the biggest risk with taking a trial and error approach to mains electricity is that it can kill you, very quickly, and very painfully.

 

[laubi02]

thanks for all your help. I have also had some other advice and suggested perhaps I can simply rewire the new light switch as per previously. simply connect the old C wires to the new L1 and the old L1 to the new L2 terminals? Disconnect the earth wire and also fit the loose black wire to an empty connector block. (see attached diagram)

Was just wondering if that sounds like something I can try without blowing anything up? (of course, I will switch the main fuse box off before doing any rewiring).