dimmer switch replacement

18 Feb 2024
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United Kingdom
I replaced dimmer switch in kitchen as one of 3 switches had stopped working. two of the switches control two separate sets of led downlighters. The other one control lights under kitchen cabinets with each cabinet having its own transformer to match the load of each set of cabinet lights. Before i replaced the switch this part of the cabinet light circuit was working but nor with the new one. i figured it was just bad luck but i wanted to check so swapped wiring on 2 of the switches and still the under cabinet circuit didnt work but the other set of downlights did work so i concluded there is nothing wrong with the new switch but it is connected to the under cabinet circuit. what i dont understand is why that circuit worked with old switch but not the new one?
Can anyone help?
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here's the old one and the new one looks similar and is from tlc and is a 3 gang 2 way push dimmer 150w nexus. old one is v-pro 1 or 2 way dimmer switch min load 10W.


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Some LEDs cannot be dimmed because of the type of power supply they use so they would have been ok with switch but not dimmer and your other set are probably dimmable.
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they were on dimmer switch before amd they worked but you're right they did not dim so they were just on off which was fine. so I dont understand what's changed.
So do you have 3 twin and earth cables at the switch and have you connected them to C and L1 on each switch.Are both each of the switches push on and off and turn to dim? Perhaps your new one won't work because it thinks there is no load on it. If you temporarily short the 2 wires for the problem circuit does it then work? If it doesn't then you probably have a problem with the power supply for the LEDs
thanks jj4091.
yes each of the (three) switches are push on/off and and turn to dim and yes live connected to C by daisy chain and each switch is connected from L1 to their respective circuits.
I think i know what you mean by shorting the problem circuit i just like the word "short" when electricity is involved. you mean just move L1 to the C to bypass the switch. Good idea will try today.
I shorted the problem circuit and the circuit does now work. So are you saying the new switch is the wrong type? if so what do i need to do to make it work? the old switch must have had a slightly different type of switch spec that wasn't fooled by the "no load" like the new one is. i still have the old switch and i might be able to take one of the individual switches off there and put it into the new one for the problem circuit. below is the old switch spec from stickers.


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All sorted. Just needed to swap one of the switches from the old dimmer to the new one. as the ones in new one Many thanks jj4091.

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