Why is it only some Halogen Downlights are Dimmable?

Sep 25, 2005 8 Replies

I have 3 downlights recessed into the landing ceiling. I am on my second dimmer (60 - 400W). The bulbs fitted are dimmable (according to the box). Presumably dimmable means they'll continue to work off a lower voltage? Why would 'non dimmable' bulbs affect the dimmer switch? If my bulbs are dimmable, what might have happened to the dimmer switch?



Jez


Probably just a chance failure. Low energy fluorescent bulbs don't work with dimmers which may be why yours are labelled as dimmable.

TonyB

Normal bulbs are usually dimmable. The energy saving (compact flourecent lamps) and normal flourecent lights are not.

It may also be a little bit off the mark to say that bulbs supplied by a dimmer switch are working off a lower voltage.

Are the downlights in the landing of the low voltage type that use a transformer? If so you would need a dimmable transformer.

A little more info on your bulbs and fittings may help.

Adam

240V versions are dimmable the ones where you use a transformer are not someone will be along in a min to tell me i'm wrong but thats how I understand it.

Yes, Vass or Cass you are wrong.

There are dimmable low voltage transformers for low voltage lighting as well as 240v dimmable lights.

The bulbs fitted are 240V (3 off) 50W GU10 Halogen Spots.

Jez

Some help on this please. I originally fitted 6 x 20w downlights on a normal transformer-from B+Q. the transformer now seems to be faulty. went to B+Q, they now sell packets of 3 x 60W DIMMABLE lights "without transformer". These are too high watts for me. Their 20W ones are descibed as dimmable. So went to website where transfomers where on sale for 150W and descibed as DIMMABLE-can I use this transformer or will I need 60W ones

60W is an unusual size for a halogen downlight. 10, 10, 35 and 50W are the norm. Are you sure that it is not 3 x 20 W lights?

If it is your transformer that is faulty then change it for an approriate one and keep your existing lights. 6 x 20 W = 120 W so the 150W transformer would be the one to use.

Adam

Adam

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