Dimmer watt rating question

[smjxm09]

If a light switch dimmer is rated at 500W for an Incandescent light will it be alright for 10x50w halogens that are 240V.

[dolph]

Not normally no.

Although I did receive confirmation from Varilight their 600W remote dimmer was rated appropriately to allow 10x50W mains halogens - that is the set up I have in one of my rooms...

[johnnyjb]

Its kinda pushin your luck havin the ratin so close,could ya make it eight, assumin yor lookin for an equal look or else use nine if your set up allows.You might have no problems but then again you might.Your supply could vary,houses are rarely 230 and do rise and fall,this would cause a small problem

[33rpm]

Just had 14 x 50w downlighters installed (700w) and was looking at a dimmer rated at 800w+ to give me 100w+ slack. The electrician installing this advised against this as he said the extra 100w capacity of the dimmer over the lights was likely to cause a hum from the dimmer. Don't how true this is but don't get any hum from the new lights / 700w dimmer he installed, but in another room where I replaced 10 x 60w with 25w bulbs I do get a hum from the dimmer. This could be because it's old or could be because the original 600w was a better match than the current 250w. Perhaps as the 25w bulbs go I should try and replace them with 60's again? Anyone else had any experience of this?

[Steve1951]

Hi
There are several factors here,

There is the simple you get what you pay for ie quality

As you said age of the dimmer.

The type of dimmer....leading edge etc.

Plus are you aware that if you have a large load dimmer it has a minimum load too so if changing your 60s to 25s has dropped below your dimmers MINIMUM load well thats probably your problem.

If you want lots of dimming going on you might consider a custom panel that people like Home Automation do or even a grid switch .

Although I am sure your electrician has done a good job lighting has become a subject all to itself and not all sparks keep up with whats available.

I am an electrician myself and often find that the customer knows more about specialised dimmers and remote control devices than I do.

Regards

Steve

[Bruce_]

At 500W, the dimmer will get quite hot. But it should work OK. I'm presuming you refer to a knob-on-wall dimmer.

"10x50w halogens that are 240V"

If that means you're using GU10 lamps, then be warned that when a lamp blow, the dimmer will likely be destroyed.

If you're using LV lamps (12V via transformer), then you really need to allow 55-60W - 50W for the lamp, plus transformer losses.

Remember that when you dim the lights, it uses less power. So 500W of load, but never set about say 75%, you will then never "overload" the dimmer.