Low-voltage lighting- Basic question

[Syke]

I have some low-voltage downlighters in a bathroom and kitchen. Each one has its own transformer and were fitted with dimmer switches. About two monthe after they were fitted, and within about a week of each other, the dimmer switches blew. The original electrician came back and said he'd had a lot of trouble with switches from that particular supplier and put on ordinary switches, pending replacements being obtained. Despite being reminded several times, nothing has been forthcoming and I have given up hope of anything now, (18 months).

My qustion is, exactly what do I require in the way of suitable dimmer switches? The bulbs are, I think, 36 and 50 watts.

Regards and thanks in advance

Pat Macguire

[meow2222]

no surprise there. At least what he fitted later was more sensible.

NT

[Lobster]

I've had similar problems with dimmer switches on halogen downlighters, and reckon you're probably better off with switches.

If you do want to go ahead and replace the dimmer - how many downlighters do you have per dimmer switch? It's just a case of ensuring the dimmer you buy has adequate rating (multiply the number of lights per switch by 50 to get the rating (in units of W or VA). and check the dimmer is compatible with electronic transformers.

eg, this one is up to 400W so you ought to be able to fit a many as 8 of your LV lights:

David

[Dave Plowman (News)]

Being obviously a chancer, he probably used cheap dimmers not suitable for LV lighting which imposes a different load than GLS.

First you need to ascertain the dimmer is suitable for 'LV' loads. Then if you have real transformers find out the rating - it may be much less than the total load allowable with GLS types. If you have electronic 'transformers' this might not apply. But I'd go for a dimmer rated at one third above the total lamp load. So if the total was 300 watts, use a 400 watt dimmer.

[stopbox]

The problem is with the transformers and not the dimmer. If it was a problem with the dimmer (e.g. you connected too many lights to a dimmer and overloaded it) it would blow the dimmer not the transformer.

You need to make sure that the transformers are dimmable with a leading edge and trailing edge dimmer.

It sounds like the dimmers used were of a low specification, or were decigned for 230v rather than the UK's higher voltage.

Regards - Jack