On 20/12/2017 10:07, RJH wrote:
Can't quite think this through. Work has just fitted a 23W CFL in an
Anglepoise type desk lamp, replacing an 11W - I asked for a brighter bulb.

It will quickly cook its control electronics and fail.

I've noticed that the shade gets very hot - maybe a little less than a
CH radiator. But still hotter than I would expect. I've also noticed
that the sticker inside seems to indicate CFL max 11W, and incandescent
max 60W.

That is about right. The 60W incandescent loses most of its heat as
invisible IR radiation which gets away quickly and the bulb envelope
still gets mad hot but nowhere near the melting point of glass.

I've pointed all this out to them, but the thinking seems to be that if
it's OK for 60W, then 23W will be fine, and they can't explain the 11W.

The CFL power supply will be stone dead at 105C when the electrolyte in
the PSU capacitors boils. Its life will be significantly shortened by
running it hot in a fixture designed for incandescents.

Is this about right? Work asked me to tell them if it gets worse - but
short of burning the building down, I'm not sure what sort of thing I
should be looking for.

Slow work day . . . :-)

Halogen desk lamps are even more dodgy. They really will burn the
building down if misused or something goes badly wrong. Shards of red
hot glass go everywhere if one explodes uncontained.

--
Regards,
Martin Brown