In article , Alan wrote:

I've just had a Pro-life 25W spiral bulb fail in a spectacular way (very
loud bang followed by lingering burnt smell). It's been fitted
approximately 6 months.

I avoid 25 watt spirals, especially of brands that are neither "Big 3"
nor home center mainstays.

It appears to me that a big run of bad 25 watt spirals was made around
2000-2001 or so. I bought one of the Lights of America brand (and that
brand I often had trouble with) and 2 of the GE brand (GE is one of the
"Big 3" and normally does well). All 3 burned out in only a few hundred
operating hours, but quietly.

I have seen only a year or two ago 25 watt spirals at Walgreens, of a
brand that I cannot remember, that appeared to me to be of similar
vintage. So I am suspicious that there are businesses that bought some of
that boatload of 2000-2001 or whatever garbage and hope to make money
reselling it under different brands.

========================

As for CFLs failing with a bang: Sadly, that was somewhat normal.

Two ways for a CFL to make a loud pop and what the manufacturers have
done about it (or should be doing):

1. A usual screw base CFL with internal electronic ballast has a filter
capacitor after the rectifier. This capacitor has limited life
expectancy, especialy at elevated temperatures. It also contains a water
solution of electrolyte, since it is an electrlytic capacitor.

If this capacitor gets too hot, the electrolyte can boil and make the
capacitor burst. The capacitor's housing is normally designed to break
without producing shrapnel of the housing.

A few years ago, quite a few people were disturbed by CFLs going POW and
occaisionally dripping electrolyte. Usually, at least one of the
following is usually the case:

* The CFL was an off-brand one
* The CFL was operated in a higher temperature environment than the
manufacturer anticipated, often in a downlight or a small enclosed
fixture
* The capacitor was not as good as the CFL manufacturer thought

What manufacturers have done about this: They have gotten better at
using capacitors that are up to the task of CFL duty.
I'm sure there will still be some capacitors popping in the future, but
I am already hearing less about capacitors popping than I heard earlier
this decade.

2. The electronic ballast shorts and a wire or a part acts as a fuse,
sometimes with a loud pop or bang. Sometimes part of the ballast gets
scorched or discolored by smoke.

If the CFL is UL listed and production units conform to units tested by
UL, then the ballast and ballast housing materials are sufficiently flame
retardant for the CFL to be reasonably safe from starting a fire.

However, I hope the manufacturers are aware that a light bulb going out
with a bang, smoke output or getting a visible scorch mark in the process
appears scary and does not make good press. I would hope they now put in
fuses to make semiconductor failures/malfunctions leading to the CFL dying
less spectacularly.

I expect less scary failures from manufacturers that hope to still be in
the CFL business 10 years from now. I think "Big 3" (Philips, GE,
Sylvania) would want to avoid bad press, so I think they mostly make
better CFLs.

- Don Klipstein )