Hi,

I have two light fittings with 60W filament bulbs attached to a double dimmer switch. When the dimmer is not dimmed one of the bulbs has a low pitch whistle. From what I recall the Dimmer is rated for two 60W bulbs.

I've changed the bulb a couple of times and noticed that the white plastic is slightly browned and must of got hot.

Is this a faulty dimmer, wiring, light fitting?

Is there a way other than process of elimination I can work out why?

Regards
Martin

Not come across a whistling lamp(bulb) before.
Is it only this fitting that does this?
If you have just the one lamp(bulb) in place, with the other off load, does it still whistle?
First thing is to check is the wiring, check for loose or damaged connections, if the fitting is scorched/burnt, it is possible that this may now need replacing as terminals may have been damaged and fitting may also be fragile due to heat. So a good inspection of the fitting is needed. Also if cables are burnt, they will need making back to unaffected insulation and bright clean copper conductor.
Also what type of dimmer do you have?
Certain dimmers will only function correctly with the correctly selected dimmer for Lamp(bulb).
On a filament lamp a resistive dimmer would be chosen.

It is only one fitting that does it. I just checked closer and the whistling/ high pitched buzzing sounds like it is coming from the bulb filament. It's not loud but you do notice it in the background when watching quiet tv.

When I turn both lights on it still does it, I also noticed when I dim the light it gets slightly louder.

Not too sure how to check what type of dimmer it is. I've tried swapping the bulb without success.

Martin

Are you sure it's not the dimmer unit making the noise? Could you read the details on the dimmer insides, and post up the dimmer type and spec?

I used to get this with some bulbs prior to the bulb failing, it was a good reminder to buy a replacement.

I have a 60W GLS lamp in one room that does the same.
Changed the lamp, whistling stopped.

I was watching the great escape on tv, suddenly i heard this sound "whuh, whuh. whuh, whuh, whuh whuh whuh. whuh, whuh..whuh whuh whuh..whu whur. I checked my filament lamp, seemed ok.

edit

Some of my equipment hums. If it knew the words it would probably sing.

But seriously some coiled filaments do vibrate excessively when driven from dimmers and if they happen to resonate at a harmonic of 100 Hz then they vibrate a lot and can be heard.

Do you have another dimmer within the house you can put on it and see if it still does it?