On Fri, 02 Dec 2005 15:54:08 -0000, (Chris
Lewis) wrote:

If it's been fine until the smoke, it's probably going bad. If
there's a wiring fault (ie: a short), dimmers usually fry
instantaneously[+]. It would be highly unusual for a wiring fault
to only draw enough current to make the dimmer overheat without
going kaboom.

You should also check the wattage of what the thing is driving.
Most dimmers are limited to 500-600W, and some to 300W. If this
is a new installation, or you recently relamped the circuit with
higher wattage bulbs, I'd strongly suspect a simple overload, which
you can resolve by choosing a higher capacity dimmer, or reducing
the quantity/wattage of the lamps.

Thanks for the advice. This dimmer was newly installed
(professionally) 3 years ago and it has been working fine until
recently. I did see the occasional spark when turning on the switch
but I was told this is common in the Skylarks and not necessarily
dangerous. None of the bulbs have been changed. It is a 600W dimmer
driving exactly 6 100W bulbs.

I guess I will just replace the switch.