Lights on Dimmer switch flicker from 2/3 to full

[hedleyp]

Hi,

I am wondering if anybody could shed some light on this...

I have two 40W bulbs in my lounge on a double switch. I replaced the switch for a double dimmer.

All was ok for a while until one of them started to flicker rapidly as I turned the dial up from about 2/3 to full, the flickering got faster as the dial was rotated closer to full, but below the 2/3 mark, the bulb appeared steady.

The other light was fine until the dimmer stopped working completely one night and I could only get full on/off, with no flickering.

I took the dimmer back to Homebase and swapped it. Wired it in last night and now both bulbs flicker rapidly when turned up from about 2/3 to full. Again, below about 2/3 the bulbs appear to be steady.

The lounge bulbs are on a seperate fuse from everything else.

Is this my wiring? Or have I managed to buy two dud dimmer switches?

It's starting to confuse me as up to now, I have never had a problem with wiring.

Thank you for your time.

/Heds

[Mark Carver]

Most dimmer controls have a maximum and *minimum* power rating. I'm surprised however that an 80w load gives difficulties, have a close look at the dimmer's specs however. Failing that try larger rated light bulbs to see what happens.

[Dave Plowman (News)]

First thing I'd look at is the *minimum* load requirement. As a rough guide it's

40 watt for a 250 watt dimmer 60 watt for a 400 watt one.

But it should be somewhere on the packaging or instructions.

[Ian_m]

Minimum load on cheap dimmers is 100W. Had to buy an expensive £15 one to dim kids bedroom 60W bulb.

[Andrew Gabriel]

Dimmers have a minimum load as well as a maximum load. Are you below the minimum load for the dimmer? You could temporarily try a 60W or 100W lamp and see if this solves the problem (although the symptom you describe is not what I've seen from running them below their minimum power rating).

When one dimmer failed to on/off mode only, did that coincide with a lamp blowing? Sounds like the Triac died, which is not unexpected on lamp failure, but if it happened otherwise, I suspect the dimmer is just too cheaply made. What make is it?

[Heds]

A big thank you for all your replies.

I changed the 40W bulbs over for 60W and they have stopped flickering. After reading your posts, I noticed on the back of the dimmer that it had a minimum load of 60W. Should have looked at that in the first instance, but I only knew about max loads. So that's something new learnt today.

So, I'm really happy!

Thank you.

/Heds