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Dimmer switch buzzes

I have just had my downlights installed in my living room on a 4 gang dimmer switch with 4 low volts lights on each switch, but the switch buzzes a lot when ever any of the lights is switched on. Is there anything that can be done to stop the buzzing. The switch was bought in screw fix (LAP 250W Dimmer)

Kind Regards

3 Answers from MyBuilder Electricians

Best Answer

Dimmers do make a noise although differnt makes and set-ups can be better or worse than others. I don't use LAP accessories, so have no experience of them, but generally the major brands like MK, Crabtree etc are better.

In an attempt to cure the problem firstly you should check that the Low Voltage transformers that were installed are compatibale with the dimmer. Some LV transformers are not capable of being dimmed (although the majority you buy these days are). If the transformers you have are not dimmable then this could cause buzzing, as the voltage is reduced (turning the dimmer knob) which in simple laymans terms causes a conflict between the electronics in the dimmer and the electronics in the LV transformer.

If the buzzing seems worse when the lights are not at full brightness? This could be a load issue. By that I mean that the combined wattage of the LV lamps (i.e the load) is not properly matched to the dimmer. For example if you have 4 x 50w lamps then the total load = 200watts. Most dimmers should be rated at 250W and the fact that the code is LAP250W suggests that it is capable of handling 250watts. This said, as the brightness is reduced, whilst the 200watt load remains the same the current and voltage characteristics change, this causes noise and heat at the dimmer switch.

Probably best to call your installer back and ask him if he can take a look at it.


Answered 17th Nov 2011

Previous experience says that the dimmer is a cheap one, more expensive brands do not buzz, brands like MK should do the trick


Answered 28th Dec 2011

is the dimmer metal if so make sure it is earthed to the switch and the back box good luck john


Answered 22nd Nov 2011

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