3 gang dimmer switch

[benjique]

Hi, apologies if this has been asked and answered before, i did a search but couldn't see it.

I need to wire a 3 gang dimmer switch. I have 5 black wires, 5 red and 3 green/yellow which i presume are neutral, live and earth?.

On the back of my dimmer I have 3 boxes with 3 connection terminals labelled, C , L2 and L1???

My question is what goes where lol and why do I have 13 wires with only nine places to fit them?

Any help will be greatly appreciated. Cheers

 

[breezer]

never assume anything,
they are probably not live neutral and earth, they are live, switched live and earth, and you are two missing.

I suggest you get an electrician to come and have a look

 

[benjique]

I did, he did all the first fix stuff and left me to second fix the plug sockets etc which are straight forward, he did me a diagram of how to wire it back up as there was a 3 gang dimmer there before (i'm just putting a more moderen looking one in it's place) but it's been thrown away.

He's now unavailable to talk to and just thought it'd be pretty easy for someone in the know.

Never mind, cheers anyway

 

[breezer]

not without seeing it it isn't easy

 

[benjique]

no, i suppose not, would a photo of the wiring help?

The old dimmer has a red loop wire going from the first "C" terminal, into the second and then the third which only leaves 6 terminals to use?.

This job has gone way over budget already and can't really afford to call another spark.

 

[breezer]

although this sounds sarcastic it is not meant to be.

Is there anything else you would like to mention?

you first asked how to wire it, you then said you had an electrician in but you lost the drawing, you now say you have a link on all the c terminals

 

[benjique]

Maybe these pics would help, maybe not?

It is to work the ceiling light, wall lights and an alcove light.
Atm it is wired to just work the ceiling light via a standard on/off switch

The pic only appears to show four black wires, there are five though, the green and yellow earth wires are approx twice as thick as the red and black?

Again. any help really appreciated but fully understand if it's not possible.

 

[breezer]

the pictures only add to my point, there is also a black in a single chock bloc?
That may be redundant which may mean its red is permanent live

Any chance of a better pic of the old switch

have you a multi meter? if not get one

 

[benjique]

Maybe these pics will be clearer

thses wires loop from one "C" terminal to another , to another


Cheers for taking the time to look, i do understand it may not be possible to help, i'm just clutching at straws lol

 

[davelx]

Some of those red wires have masking tape on them - is there something written on that tape? If so, what? The only reason for putting the tape there is to label the wires.

What is the single gang switch in the picture for?

There are five cables - mu guess would be that you have loop-in/loop-out cables plus 1 to each light. But you need a multimeter to correctly identify them.

 

[benjique]

Nothing on the masking tape, maybe put there to indentify which did what some time ago.

The single switch is operating the ceiling light atm, the sparky disconnected the old three gang dimmer and fitted that switch just so I had a working light for the room.

I don't have a multi meter but what's the worst that could happen if incorrectly wired, would it not just trip at the fuse box until correctly wired?

 

[davelx]

OK, that helps.

The two red wires going into the"C" terminal of the single gang switch are almost certainly going to be the feed loop-in, loop-out wires. You should be able to confirm this by checking if they are live with a suitable meter, voltage detector or, if you have no other choice, a neon test screwdriver. That terminal should be live whether the switch is on or off. The other two free red wires should NOT currently be live under any conditions.

If that proves to be the case, then the single wire in the single gang switch connects to the ceiling light, and the other two free reds connect to the other two lights.

You could verify that by (with the power off) swapping the single reds around in turn on the switch and checking that each one allows you to control a different light.

If all this checks out, then two reds currently tied together in the switch "C" terminal need to connect to the linked C terminals on the 3-gang dimmer (you can put them in 2 different dimmers), and the three remaining reds go to the three L1 terminals on the dimmers, one to each.

The blacks all stay commoned in the block and the earths all stay commoned in their block. There should really be 5 earths - one from each cable, I can only see 3 in the photo. If any of the earths on the cables to the lights are not connected then you cannot use a fitting that requires an earth at that position.

 

[benjique]

After looking at the wiring, this is my idea.

Atm 2 of the red wires going into the single temporary switch go into the "C" terminal and the other goes into the L1, this set up already works the centre ceiling light, so...

If i take out the loop wires that are in my old dimmer box, connect them into the new one in the "C" terminals exactly as they are shown in the picture, then take the 2 red wires that go into the "C" on the temporary switch, put one into the left hand C terminal, the other into the right hand C terminal so then i have the feed going in, looping across, then going out again.

Take the red wire that is in the L1 terminal of the temporary switch and put it into any of the L1 terminals on my new dimmer (depending on which knob I wish to operate which light, if I put it into the left L1 terminal then the left knob will operate the ceiling light?)

Then take the other two red wires that have the blue tape on in the picture and connect those to each of the other two L1 terminals, again depending on which knob I decide to operate each light.

Take a short piece of earth wire, connect it to the block that the 3 earths are connected to, then connect the other end to the earth screw on the back of the new face plate.

Leave all the black wires connected to the block they are already in, so in effect i will be doing nothing to the blacks at all...

Does that make sense?

If so what do you lads think?

 

[benjique]

Cheers mate, I was typing my idea at the same time, it's more or less the same isn't it?

What about my earthing idea?

How do you mean That I wouldn't be able to use a fitting that requires an earth? Do you mean my new dimmer faceplate?

 

[benjique]

sorry to bump this but really need to get this done in the morning lol, just what are the complications at having only 3 earth wires, can i still connect my new metal dimmer?