Electrical Question

1000 watt dimmer switch buzzing and over heating

I recently got my house re-wired and in the lounge I have two sets of low voltage (24v) spotlights. One circuit has 12 x 50 watt bulbs (600w) and the other circuit has 6 x 50 watt bulbs (300w).

I designed it this way on the back of buying a 2 gang 1000watt dimmer switch which states that each gang can take a minimum of 150 watt and a max of 1000 watt.

However when we did the big switch on both switches give off a very loud buzzing noise (too much to live with) and in fact the smaller load 300 watt switch gives off an even bigger buzz and after 10 mins the light starts to flicker and a burning smell comes from the switch.

I first thought it was a faulty switch and the supplier sent me a replacement free of charge - but when we switched it over it still has the exact same problem.

All the other circuits upstairs were wired the same way (transformers with each light) but with lower loads (up to 300w) and all work ok off standard dimmers - Can anyone explain? Do i just have a cheap 1000 watt dimmer as it was off ebay or is there a bigger under lying problem.

Problem is house is now all decorated nearly and not simple to run another cable

Any help will be VERY much appreciated

4 Answers

Best Answer

Agree with substructure in part, particularly as your supplying a 600W low voltage load.
Is the dimmer compatable with low voltage lights?
Is there a limit to how many transformers the dimmer can control?
And finally are the transformers compatable with the dimmer?
Could you not convert all fittings to GU10? I've found much less problems with mains voltage over ELV.

Answered 4th Mar 2012

EPC Electrical and Building Services

Member since 4 Mar 2009

A decent 1000w dual dimmer will be £80 ish! so my guess is its cheap imported dimmers and or cheap transformers that together are not compatible?

There are two types of dimmers on the market, trailing edge and leading edge. One is much more expensive than the other and gives better results.

Answered 4th Mar 2012

Electrical Safety Services

Member since 17 Oct 2011

Make sure the transformers for the lights are dimmable, if that is okay, then buy a better dimmer. Would suggest crabtree, MK, or volex.

Answered 4th Mar 2012

Christian V Electrical LTD

Member since 22 May 2009

E-BAY MMMMM i would say youve bought cheap imitation stuff from china,some good some bad but if the priceis too good to be true then it is ,get decent ones with the kitemark logo mk ect are good fittings ,never skimp on building products to save a few bob cause this is wat happens ,especially where elecs are concerned ,burning smells you are lucky house never went up.

Answered 4th Mar 2012


Member since 7 Jun 2008

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