2 Gang Double Switch Problem

Juney · Feb 13, 2019

I have a 2 gang dimmer switch which work both lights in the room ok (a main and a side light) The other switch has never worked properly only switching the main light on, but won’t switch off the light when dimmer is on, it just gives the full power to it. In the switch there are 3 wires, a red, a yellow with red sleeve, and a blue. Does this mean that the switch has never worked 2 lights? How do I wire the switch, so that it switches off when the dimmer is on? Any help appreciated, thanks

dinger809 · Feb 13, 2019

That does sound like a two way wired switch. My advice is the get an electrician to look at it and see what the issue is, as it may need a bit of investigation and some wiring at the switches altered

littlespark · Feb 14, 2019

Can you get pics of the wiring behind the switch? Is that all there is? Red/yellow/blue?
Also in the pic, the terminals of the switches and what is connected where.

Is there a short link between the two switches?

Can you confirm this is the only switch for the room? (Ie it’s not a 2 way circuit)

What is it you are trying to achieve with the switches?
Ie one switch for the ceiling light, one for the wall, or just one switch for both lights?

Juney · Feb 14, 2019

Thank you so much for your reply. I will take pictures of each switch. One is a two gang dimmer which I have wired and seems to be working fine. It works the main ceiling light, and a wall light. The other 2 gang switch has never worked properly since we moved in. If the main ceiling light is on at the dimmer, the other switch will not switch it off. You could switch the main light on from there, but you cannot switch it off if dimmer is on. I will take some pics and get back to you, and thanks for your help

Juney · Feb 14, 2019

Dimmer at different angles so you can see where each wire goes. The single picture is the switch at the other side of the room. I don’t think it can work both lights as there are not enough wires, but if the main light could be turned off when leaving the room at that side, it would be good. Otherwise we will have to keep walking over and switching off!

Juney · Feb 14, 2019

Maybe I have got something wrong in the dimmer. Let me know if you need better pictures, and thanks

telectrix · Feb 14, 2019

nbot sure but think maybe 1 or 2 of the reds in pic 3 should be in L1 instead of common.

multimick · Feb 14, 2019

picture 4 switch ,blue and red need separating

westward10 · Feb 14, 2019

Those connections in the bottom pic must be incorrect.

Wilko · Feb 14, 2019

westward10 said:
Those connections in the bottom pic must be incorrect.

A swag from me would be (bottom pic) to move red to L1 and yellow sleeved red to L3. But I would test before changing anything. I have seen a number of these setups that have been "adapted" over time to account for failures in the switches. At least there are some pics now to refer back to

.

dinger809 · Feb 14, 2019

I think here is an error in both switches.
The red and blue in pic 4 definitely need separating, but in the other pics, it appears that the non dimming switch has both sleeves blues going into it, when one should be going into the dimmer. It appears there are two, two-way switches there, but seem to have got muddled up

Juney · Feb 14, 2019

telectrix said:
nbot sure but think maybe 1 or 2 of the reds in pic 3 should be in L1 instead of common.

Do you mean one of the two reds, or one or both of them? I will try tomorrow in the daylight, thanks

telectrix · Feb 14, 2019

without belling the cables it'strial and error.

1. it works
2. it don't work
3. bang.

Juney · Feb 14, 2019

dinger809 said:
I think here is an error in both switches.
The red and blue in pic 4 definitely need separating, but in the other pics, it appears that the non dimming switch has both sleeves blues going into it, when one should be going into the dimmer. It appears there are two, two-way switches there, but seem to have got muddled up

Both of the connectors in the first 3 pics are dimmers. It a double dimmer switch. At the moment it works and dims both lights. So you think the two blues going in together shouldn’t be? Any idea where I should move one of them to? Sorry to be a pain.

Juney · Feb 14, 2019

telectrix said:
without belling the cables it'strial and error.

1. it works
2. it don't work
3. bang.

I’ve had a few trials and errors, but no bangs as yet lol

littlespark · Feb 14, 2019

you wont get a bang. Theres no neutrals at the switches... just don't attach any cables to the earth.

Deleted member 26818 · Feb 14, 2019

I thought the symbol with the sine wave and the arrow is for the dimmed output?
Also, I’m counting 2 of each colour at the 2 gang dimmer switch, which suggests two 3 core cables?

Marcus Vaughan · Feb 14, 2019

I suspect it’s actually 2 way 3 wire, considering there are 5 cores at the dimmer.

I would test to see which is the switch line but suspect it’s the blue currently in the left dimmer in L2.

If it was 3 wire then the red link would need to go into L1 in the dimmer - not the common, and the plate switch would be blue into L1, red into common, yellow into L2.

Deleted member 26818 · Feb 14, 2019

It’s not 5 cores, it’s six.

Marcus Vaughan · Feb 14, 2019

spinlondon said:
It’s not 5 cores, it’s six.

I count 5 in that left dimmer?

The other dimmer is just one way (I think).

telectrix · Feb 14, 2019

I thought the symbol with the sine wave and the arrow is for the dimmed output?

no.it's the common.

dinger809 · Feb 14, 2019

Juney said:
Both of the connectors in the first 3 pics are dimmers. It a double dimmer switch. At the moment it works and dims both lights. So you think the two blues going in together shouldn’t be? Any idea where I should move one of them to? Sorry to be a pain.

One of the sleeved blues should go into the other switch, without looking at the back box or belling it out, it’s impossible to know which one. The rule with two way lighting is, whatever colours go into L1,L2 and Common in the main switch goes into the same one in the other, si your yellow, blue and red should be in the corresponding terminals in both switches.

Without further investigation, that’s the best I can do

Good luck

Deleted member 26818 · Feb 14, 2019

If that’s the common, then it shouldn’t be used to feed the second switch.
The live into the first switch, needs to go to either L1 or L2, with the switched live in the other L1 or L2 terminal.

Marcus Vaughan · Feb 15, 2019

spinlondon said:
If that’s the common, then it shouldn’t be used to feed the second switch.
The live into the first switch, needs to go to either L1 or L2, with the switched live in the other L1 or L2 terminal.

I was thinking that the feed for the plate is going into the one way dimmer common first.....

Deleted member 26818 · Feb 15, 2019

Marcus Vaughan said:
I was thinking that the feed for the plate is going into the one way dimmer common first.....

Could be.
Either way it would make the 2 way common live all the time.
Live feed in needs to go to L1 or L2.
Switched live from the other L1 or L2 terminal.
Unless the switched live is at the other end, but then you wouldn’t need 3 core between the switches.

Move the blue from L1 to common.
Move the blue and yellow from L2 to L1.
Move the 2 reds from common to L2.
At the other end move the blue from L3 to L2.

Deleted member 26818 · Feb 15, 2019

Weird, I’m in middle of four lighting threads at the moment.
Two here and two on another forum.

Juney · Feb 18, 2019

Thank you all so much for your replies. I have been poorly for a few days so just catching up. I will try some of your suggestions. Spinlondon, your remedy sounds the most simple for my little brain I will try tomorrow if I am feeling better and report back

Juney · Feb 24, 2019

Quick update. I have been in hospital (no I didn’t blow myself up lol) so haven’t even looked at it, but I will do in a few days maybe, and try some of your suggestions, and report back. Thank you all for taking time to reply, it is much appreciated