In article .com,
writes:
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.

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?

--
Andrew Gabriel