one light switch stopped working - baffled by wiring!

[MasterMark]

Hello all, I'm an electrics novice but pretty confused. I have a 3 gang, dimmable light switch.

Left switch - 2 external dimmable led lights.
Middle switch - 10 led kitchen ceiling dimmable downlights.
Right switch - 7 led undercabinet kitchen dimmable downlights (the different-looking module)

All working great since full refurb in 2017. Then the right switch stopped working properly - felt like the button wouldn't "click" in (very occasionally it did and lights would work fine).

Opened it up, fiddled a bit, and it now clicks nicely again. But lights won't switch on, there's a wire that has come unconnected which you can see in the photo. And much more complicated wiring than I was expecting - the switches are 1-way, not 2-way, yet L2 is getting used.

If someone could explain what's going on / how to fix this, would be much appreciated!

(If needed I have a replacement dimmer module I could use to replace the one on the right, that's the other photo).

 

[ericmark]

Right switch 60 - 400 VA, so 7 LED's must be at least 8.6 watts, since likely wanting to run at 50% then really double that, so around 18 watt each, which is unlikely.

The other two are 5 to 75 watt so well within spec.

As to wire, seems most likely this

terminal on centre switch, but can only guess.

The replacement seems OK.

 

[SUNRAY]

I look like the middle switch has 3 wires into 'L', in which case I'd assume the odd wire goes into '~'

Did you disconnect the wires to the right switch while you had it apart?

 

[SUNRAY]

Are the undercupboard lights in 2 sets, ie each side of the kitchen?

 

[MasterMark]

Thanks all! So to answer some of the questions:

1. The right switch lights (undercabinet) - can't remember wattage, but unlikely to be more than 5w each.
2. I did indeed disconnect the wires on the right switch, but then put them back as they were.
3. Great point re under-cupboard lights - yes, they are 2 different sides (5 on one side, 2 on the other).
4. I have put the loose wire into the middle switch ~ as suggested.
5. I will try and replace the right module with the new one, seems if that does anything.

I will report back after that's done!

 

[MasterMark]

Ok, so replaced with the new module on the right. But the lights still don't turn on.

 

[SUNRAY]

Ok, so replaced with the new module on the right. But the lights still don't turn on.

are these extra low voltage LEDs with 2 different powersuppllies? can we have pictures
Do you have any sort of test equipment?


As a test to rule out the dimmer, I'd connect all 3 wires in that dimmer into one single terminal.

or a choc block. of course any re-wiring is done with the power off for safety.

 

[MasterMark]

So the undercabinet round lights are 3W Leyton round cabinet downlights. There are 7 in total - 5 down one side of the kitchen, 2 on the opposite side (if that's what you mean by "2 different power supplies"?

Re putting all 3 wires into one terminal - I will try that tomorrow morning in daylight. But I replaced the old module with the new one in the first picture, so I guess that should be working fine (unless I'm VERY unlucky!)

Test equipment - I only have a fairly cheap and cheerful multimeter, not sure if that would be of any use!

 

[terryplumb]

Your switch plate should be earthed ,and it isn't !!

 

[SUNRAY]

Your switch plate should be earthed ,and it isn't !!

I'll thank you, I thought I'd mentioned it

 

[terryplumb]

8 out of 10....must try harder SUNRAY

 

[SUNRAY]

So the undercabinet round lights are 3W Leyton round cabinet downlights. There are 7 in total - 5 down one side of the kitchen, 2 on the opposite side (if that's what you mean by "2 different power supplies"?

Re putting all 3 wires into one terminal - I will try that tomorrow morning in daylight. But I replaced the old module with the new one in the first picture, so I guess that should be working fine (unless I'm VERY unlucky!)

Test equipment - I only have a fairly cheap and cheerful multimeter, not sure if that would be of any use!

I'm making a guess the two brown wires at the dimmmer go one to each group.
The Leyton undercupboard lights I know are

12 volt units and require a transformer/powersupply/driver which are often screwed to the bottom of the cupboard or laying on top.

 

[SUNRAY]

8 out of 10....must try harder SUNRAY

Just found I'd started a reply on my phone while coming home.