I talked with a guy in a large department store replacing flourescent bulbs
about the 1-2 problem. He said a failing bulb also extinguished the good
bulb but his procedure was to rather than try to find the bad bulb to simply
replace them both as they are cheap and aged at the same rate so that the
"good" bulb was nearly aged out anyway.


wrote in message
...
Has anyone noticed that Compact Florescent bulbs burn out at the same
time? The first time I thought it was a coincidense, but it just
happened again. The last time I had 2 of them in a kitchen ceiling
fixture. I installed both at the same time, same fixture, on the same
switch. One bulb burned out, a few days later the other one did.
(these were the ones that stick straight out of the base)

Now, it's the bathroom. The bathroom has one switch that controls two
identical wall mounted fixtures on each side of the mirror. About 10
days ago I turned on the bathroom lights and one of the CF bulbs went
up in smoke (literally). There was a shower of sparks in the base of
the bulb, and a puff of smoke, which ended the bulb. I replaced that
one with a standard bulb. Today I went in the bathroom, flipped on
the lights and the other CF bulb started flashing on an off and
seconds later it got real dim and then died. (these were the twisted
type, and both were installed at the same time).

This is more than coincidense.

Note: There is nothing wrong with the wiring, switch or fixtures.

I am going back to standard bulbs though. The CF bulbs do not have
anywhere near the life they state, in fact standard bulbs seem to last
much longer. For the price of these CF bulbs and their short lives, I
dont think I am saving any money. Sure they use about 60% less power,
but they cost ten times as much as regular bulbs. Besides that, after
watching that one go up in smoke, I think they are a fire hazzard.

snippage

Has anyone noticed that Compact Florescent bulbs burn out at the same
time?
Today I went in the bathroom, flipped on
the lights and the other CF bulb started flashing on an off and
seconds later it got real dim and then died. (these were the twisted
type, and both were installed at the same time).

This is more than coincidense.

Note: There is nothing wrong with the wiring, switch or fixtures.

I am going back to standard bulbs though.
Sure they use about 60% less power,
but they cost ten times as much as regular bulbs. Besides that, after
watching that one go up in smoke, I think they are a fire hazzard.

I don't know where you buy the bulbs, but ten times cost is way out of line.
I pay more like 2 bucks per fluorescent when bot in four or six packs. The
price differential between the local hardware store and Home Depot is about
3 to 4 times the cost. Are you buying on the corner store? I also am getting
very long life from them, and am getting the same light output for about a
third to a quarter of the wattage. Three or four years ago I replaced about
35-40 incandescents in and outside the house with CF, and only two or three
have burned out, at different times, not together. I am convince that the
burn-outs were premature due to bad qual. control in the earlier models.
Either you have bought older stock, a bogus brand, or may have surges,
moisture (bath) or other probs with your wiring or switch system. I think,
at least from my experience, they are reliable and cheap for what they do.

I understand that many facilities with a large number of lighting
fixtures (whether fluorescent or incandescent) will figure out a
schedule according to which they simply replace all the bulbs/tubes at
once rather than have to keep coming back and replace one or two here
and there. Costs less in the long run.

Perce


On 07/26/05 01:47 am Blue tossed the following ingredients into the
ever-growing pot of cybersoup:

I talked with a guy in a large department store replacing flourescent bulbs
about the 1-2 problem. He said a failing bulb also extinguished the good
bulb but his procedure was to rather than try to find the bad bulb to simply
replace them both as they are cheap and aged at the same rate so that the
"good" bulb was nearly aged out anyway.

There was a recall of compact flourscent bulbs because of fire hazard. I
suspect with the shower of sparks you had you had the bad bulbs.


wrote in message
...
Has anyone noticed that Compact Florescent bulbs burn out at the same
time? The first time I thought it was a coincidense, but it just
happened again. The last time I had 2 of them in a kitchen ceiling
fixture. I installed both at the same time, same fixture, on the same
switch. One bulb burned out, a few days later the other one did.
(these were the ones that stick straight out of the base)

Now, it's the bathroom. The bathroom has one switch that controls two
identical wall mounted fixtures on each side of the mirror. About 10
days ago I turned on the bathroom lights and one of the CF bulbs went
up in smoke (literally). There was a shower of sparks in the base of
the bulb, and a puff of smoke, which ended the bulb. I replaced that
one with a standard bulb. Today I went in the bathroom, flipped on
the lights and the other CF bulb started flashing on an off and
seconds later it got real dim and then died. (these were the twisted
type, and both were installed at the same time).

This is more than coincidense.

Note: There is nothing wrong with the wiring, switch or fixtures.

I am going back to standard bulbs though. The CF bulbs do not have
anywhere near the life they state, in fact standard bulbs seem to last
much longer. For the price of these CF bulbs and their short lives, I
dont think I am saving any money. Sure they use about 60% less power,
but they cost ten times as much as regular bulbs. Besides that, after
watching that one go up in smoke, I think they are a fire hazzard.

wrote in message
...
Has anyone noticed that Compact Florescent bulbs burn out at the same
time? The first time I thought it was a coincidense, but it just
happened again. The last time I had 2 of them in a kitchen ceiling
fixture. I installed both at the same time, same fixture, on the same
switch. One bulb burned out, a few days later the other one did.
(these were the ones that stick straight out of the base)

Now, it's the bathroom. The bathroom has one switch that controls two
identical wall mounted fixtures on each side of the mirror. About 10
days ago I turned on the bathroom lights and one of the CF bulbs went
up in smoke (literally). There was a shower of sparks in the base of
the bulb, and a puff of smoke, which ended the bulb. I replaced that
one with a standard bulb. Today I went in the bathroom, flipped on
the lights and the other CF bulb started flashing on an off and
seconds later it got real dim and then died. (these were the twisted
type, and both were installed at the same time).

This is more than coincidense.

Note: There is nothing wrong with the wiring, switch or fixtures.

I am going back to standard bulbs though. The CF bulbs do not have
anywhere near the life they state, in fact standard bulbs seem to last
much longer. For the price of these CF bulbs and their short lives, I
dont think I am saving any money. Sure they use about 60% less power,
but they cost ten times as much as regular bulbs. Besides that, after
watching that one go up in smoke, I think they are a fire hazzard.

I have three of them in a kitchen fixture. One of them burned out in a
relatively short time period, replaced it and all OK for now. Got them
from Home Depot, brought it back and got another one based on 7 yr. life
warranty. I guess we both experienced the "infant mortality" syndrome.
MLD

Blue wrote:

I talked with a guy in a large department store replacing flourescent bulbs
about the 1-2 problem. He said a failing bulb also extinguished the good
bulb but his procedure was to rather than try to find the bad bulb to simply
replace them both as they are cheap and aged at the same rate so that the
"good" bulb was nearly aged out anyway.



Apples and oranges....

That guy was probably referring to lamps in fixtures where two bulbs are
fed by one ballast. That's not the case with the kind of CFs you describe.

There is no technical reason I can think of relating to the bulbs
themselves which would explain why two CFs fail "about the same time"
other than excellent design life calculations and manufacture with
identical molecules in the same places in all the components of the
bulbs. G

But, possibly the second CF in the event you described was damaged by an
inductive spike caused by the first bulb arcing across the line. That's
more of a cause and effect relating to the type of failure of the first
bulb than it would be a design life factor.

Your "short life" problems are likely due to poor quality bulbs or
something strange about your home's power, like frequent spikes and
surges. I've been using about 15 CFs for over 5 years in various spots
in our home, including in the outside lamps straddling our front door,
and haven't lost one yet.

Jeff


--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

Jeff Wisnia wrote:
Blue wrote:

I talked with a guy in a large department store replacing
flourescent bulbs about the 1-2 problem. He said a failing bulb
also extinguished the good bulb but his procedure was to rather than
try to find the bad bulb to simply replace them both as they are
cheap and aged at the same rate so that the "good" bulb was nearly
aged out anyway.


Apples and oranges....

That guy was probably referring to lamps in fixtures where two bulbs
are fed by one ballast. That's not the case with the kind of CFs you
describe.

That makes sense. It would also make sense to replace all the CF's that
are in the same fixture and have had the same usage as the ones that still
work are likely close to the end of their life and are likely now not as
bright as when new.


There is no technical reason I can think of relating to the bulbs
themselves which would explain why two CFs fail "about the same time"
other than excellent design life calculations and manufacture with
identical molecules in the same places in all the components of the
bulbs. G

But, possibly the second CF in the event you described was damaged by
an inductive spike caused by the first bulb arcing across the line.
That's more of a cause and effect relating to the type of failure of
the first bulb than it would be a design life factor.

Your "short life" problems are likely due to poor quality bulbs or
something strange about your home's power, like frequent spikes and
surges. I've been using about 15 CFs for over 5 years in various spots
in our home, including in the outside lamps straddling our front door,
and haven't lost one yet.

Jeff

--
Joseph Meehan

Dia duit

"Percival P. Cassidy" wrote:

I understand that many facilities with a large number of lighting
fixtures (whether fluorescent or incandescent) will figure out a
schedule according to which they simply replace all the bulbs/tubes at
once rather than have to keep coming back and replace one or two here
and there. Costs less in the long run.

Yep, when I worked in an office once, they had a service come out and
change all the bulbs all in the overhead lights. They did this on a
periodic basis. The workers had stilts so they could reach the lights
without ladders.

Helped keep the place nice and bright as well.

wrote in message
...
Has anyone noticed that Compact Florescent bulbs burn out at the same
time? The first time I thought it was a coincidense, but it just
happened again. The last time I had 2 of them in a kitchen ceiling
fixture. I installed both at the same time, same fixture, on the same
switch. One bulb burned out, a few days later the other one did.
(these were the ones that stick straight out of the base)

Now, it's the bathroom. The bathroom has one switch that controls two
identical wall mounted fixtures on each side of the mirror. About 10
days ago I turned on the bathroom lights and one of the CF bulbs went
up in smoke (literally). There was a shower of sparks in the base of
the bulb, and a puff of smoke, which ended the bulb. I replaced that
one with a standard bulb. Today I went in the bathroom, flipped on
the lights and the other CF bulb started flashing on an off and
seconds later it got real dim and then died. (these were the twisted
type, and both were installed at the same time).

This is more than coincidense.

Note: There is nothing wrong with the wiring, switch or fixtures.

I am going back to standard bulbs though. The CF bulbs do not have
anywhere near the life they state, in fact standard bulbs seem to last
much longer. For the price of these CF bulbs and their short lives, I
dont think I am saving any money. Sure they use about 60% less power,
but they cost ten times as much as regular bulbs. Besides that, after
watching that one go up in smoke, I think they are a fire hazzard.

Am I the only one who have had good luck with them?

I started using them 15 years ago and they are at or living beyond expected
life. I have a mini spiral type in a porch fixture that I installed in the
early spring of 04. It is left on continuously and has has not quit yet. I
do avoid using them base up where the heat can reduce the life. I am also
avoiding brands such as GE and Lights of America that seem to have a problem
with lamp life.
John

On 7/26/2005 8:06 AM or thereabouts, Percival P. Cassidy appears,
somewhat unbelievably, to have opined:

I understand that many facilities with a large number of lighting
fixtures (whether fluorescent or incandescent) will figure out a
schedule according to which they simply replace all the bulbs/tubes at
once rather than have to keep coming back and replace one or two here
and there. Costs less in the long run.

Perce


On 07/26/05 01:47 am Blue tossed the following ingredients into the
ever-growing pot of cybersoup:

I talked with a guy in a large department store replacing flourescent
bulbs about the 1-2 problem. He said a failing bulb also extinguished
the good bulb but his procedure was to rather than try to find the bad
bulb to simply replace them both as they are cheap and aged at the
same rate so that the "good" bulb was nearly aged out anyway.



True. Having worked in retail for over 20 years I have seen this several
times. The firm I work for used to use a service that traveled all over
the U. S. They would come around about every 3 years and change out
every fluorescent tube in the building using scissor lifts. They worked
overnight and would take a couple of days to finish a store. I remember
talking with some of the crew members. One of them told me he got a lot
of funny reactions from people when he replied to their question of
"What do you do for a living?" with "I change light bulbs."

We now use a different firm which comes around once a month and replaces
only the tubes that are out at that time.

--
As a child, my parents thought I was an idiot-savant.
Now, however, it is rather clear that I'm simply an idiot.

In article ,
wrote:

Has anyone noticed that Compact Florescent bulbs burn out at the same
time? The first time I thought it was a coincidense, but it just
happened again. The last time I had 2 of them in a kitchen ceiling
fixture. I installed both at the same time, same fixture, on the same
switch. One bulb burned out, a few days later the other one did.
(these were the ones that stick straight out of the base)

The explanation may be heat. A significant heatwave has
made the national news a little bit. Integral-ballast compact
fluorescents, especially 15 watts or more, often have problems with
ceiling fixtures and small enclosed fixtures and downlights. Philips SLS
non-dimmable versions up to 20 watts are better, and their 23 watt
non-dimmable version is also rated for use in recessed ceiling downlights.

Compact fluorescents do not take heat as well as incandescents, and
produce more non-radiant heat than incandescents of same wattage (but at
least normally less than incandescents of same light output). Compact
fluorescents produce little infrared, so almost all energy failing to
become visible light becomes heat in the fixture as opposed to a fair
amount materializing in the same room but outside the fixture.

Now, it's the bathroom. The bathroom has one switch that controls two
identical wall mounted fixtures on each side of the mirror. About 10
days ago I turned on the bathroom lights and one of the CF bulbs went
up in smoke (literally). There was a shower of sparks in the base of
the bulb, and a puff of smoke, which ended the bulb. I replaced that
one with a standard bulb. Today I went in the bathroom, flipped on
the lights and the other CF bulb started flashing on an off and
seconds later it got real dim and then died. (these were the twisted
type, and both were installed at the same time).

This is more than coincidense.

Maybe heat, maybe a line voltage surge from lightning damaging but not
outright killing the bulbs (line voltage surge damage is more often but
not necessarily either immediately fatal or negligible-zero).

Note: There is nothing wrong with the wiring, switch or fixtures.

I am going back to standard bulbs though. The CF bulbs do not have
anywhere near the life they state, in fact standard bulbs seem to last
much longer. For the price of these CF bulbs and their short lives, I
dont think I am saving any money. Sure they use about 60% less power,
but they cost ten times as much as regular bulbs. Besides that, after
watching that one go up in smoke, I think they are a fire hazzard.

I now see not-too-bad compact fluorescent bulbs for about $4-$5 apiece,
great ones for about $8, and frequent promotional specials at home centers
for ones at least "fair" amounting to $2 per bulb or less.

Power savings are more typically 65-70%, in good cases 75%.

Some compact fluorescents are bad and some situations do not call for
them:

* Dollar store compact fluorescents in my somewhat major experience are
lousy to outright rubbish. I buy them mainly to report on them.
Complaints are many, including color, light output, light output in
comparison to claims of light output, and a high rate of scary early
failures.

* I have seen a bad run or two of 25 watt spirals, of both GE and Lights
of America brands.

* Lights of America is a brand where I have had a disproportionate share
of early failures and other disappointments, although their spirals made
after 2001 may be as good as other brands of spirals.

* Compact fluorescents, especially of higher wattages and/or other than
non-dimmable Philips SLS types up to 23 watts, often do not do well in
small enclosed fixtures and downlights due to heat buildup.
Most commercial/institutional buildings with compact fluorescent ceiling
fixtures have different bulbs that do not include ballasts, and the
ballasts are located in the fixture usually out of view.

* Fluorescents in general, and especially ones smaller and of lower
wattage than 4-footers, tend to be uneconomical when on-time is short.
Low duty cycle makes payback of energy savings longer, and frequent
starts cause extra wear. Rated life is typically specified by the
manufacturer to be typically achieved with 3 hours average runtime per
start. I generally do not recommend compact fluorescents for motion
sensor lights, closet lights, refrigerator lights, nor for bathroom lights
that are mostly used for short trips.

Some more details in:

http://www.misty.com/~don/cfx.html

- Don Klipstein )

In article , Blue wrote:
I talked with a guy in a large department store replacing flourescent bulbs
about the 1-2 problem. He said a failing bulb also extinguished the good
bulb but his procedure was to rather than try to find the bad bulb to simply
replace them both as they are cheap and aged at the same rate so that the
"good" bulb was nearly aged out anyway.

This is mainly for 2-foot and longer fluorescents, as well as some
ballastless compact fluorescents in 2-bulb fixtures that have separate
2-bulb ballasts somewhere in the fixture (not the usual screw-base compact
fluorescents).

- Don Klipstein )

In article ,
wrote:

On Tue, 26 Jul 2005 14:01:55 GMT, "Art"
wrote:

There was a recall of compact flourscent bulbs because of fire hazard. I
suspect with the shower of sparks you had you had the bad bulbs.

Could you please enlighten us about where this recall can be found.
These bulbs are GE brand. So they are not some off the wall brand,
even though they say (made in China).

I know of one affecting one model known to be sold under 2 brands, and
I guess not all production runs of that model.

Brands affected are "Commercial Electric" and "DuraBright". The model
is a 3-way spiral with highest brightness claimed to be equal/comparable
to 150 watts incandescent.

The link:

http://www.cpsc.gov/CPSCPUB/PREREL/prhtml05/05064.html

Please keep in mind that screw-in compact fluorescents equivalent to
more than 60-75 watts incandescent often do not do well in small enclosed
fixtures nor in downlights.

Other compact fluorescent stuff - the bad, the ugly and the mostly good:

My "compact fluorescent top page",

http://www.misty.com/~don/cfx.html

- Don Klipstein )

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Tue, 26 Jul 2005 09:06:14 -0400, "Percival P. Cassidy"
wrote:

I understand that many facilities with a large number of lighting
fixtures (whether fluorescent or incandescent) will figure out a
schedule according to which they simply replace all the bulbs/tubes
at once rather than have to keep coming back and replace one or two
here and there. Costs less in the long run.

I refuse to relamp.




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Version: PGP 7.1

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=wrRQ
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--
-john
wide-open at throttle dot info

Don Klipstein wrote:

In article ,
wrote:

Has anyone noticed that Compact Florescent bulbs burn out at the same
time? The first time I thought it was a coincidense, but it just
happened again. The last time I had 2 of them in a kitchen ceiling
fixture. I installed both at the same time, same fixture, on the same
switch. One bulb burned out, a few days later the other one did.
(these were the ones that stick straight out of the base)

The explanation may be heat. A significant heatwave has
made the national news a little bit. Integral-ballast compact
fluorescents, especially 15 watts or more, often have problems with
ceiling fixtures and small enclosed fixtures and downlights. Philips SLS
non-dimmable versions up to 20 watts are better, and their 23 watt
non-dimmable version is also rated for use in recessed ceiling downlights.

Compact fluorescents do not take heat as well as incandescents, and
produce more non-radiant heat than incandescents of same wattage (but at
least normally less than incandescents of same light output). Compact
fluorescents produce little infrared, so almost all energy failing to
become visible light becomes heat in the fixture as opposed to a fair
amount materializing in the same room but outside the fixture.

Now, it's the bathroom. The bathroom has one switch that controls two
identical wall mounted fixtures on each side of the mirror. About 10
days ago I turned on the bathroom lights and one of the CF bulbs went
up in smoke (literally). There was a shower of sparks in the base of
the bulb, and a puff of smoke, which ended the bulb. I replaced that
one with a standard bulb. Today I went in the bathroom, flipped on
the lights and the other CF bulb started flashing on an off and
seconds later it got real dim and then died. (these were the twisted
type, and both were installed at the same time).

This is more than coincidense.

Maybe heat, maybe a line voltage surge from lightning damaging but not
outright killing the bulbs (line voltage surge damage is more often but
not necessarily either immediately fatal or negligible-zero).

Note: There is nothing wrong with the wiring, switch or fixtures.

I am going back to standard bulbs though. The CF bulbs do not have
anywhere near the life they state, in fact standard bulbs seem to last
much longer. For the price of these CF bulbs and their short lives, I
dont think I am saving any money. Sure they use about 60% less power,
but they cost ten times as much as regular bulbs. Besides that, after
watching that one go up in smoke, I think they are a fire hazzard.

I now see not-too-bad compact fluorescent bulbs for about $4-$5 apiece,
great ones for about $8, and frequent promotional specials at home centers
for ones at least "fair" amounting to $2 per bulb or less.

Power savings are more typically 65-70%, in good cases 75%.

Some compact fluorescents are bad and some situations do not call for
them:

* Dollar store compact fluorescents in my somewhat major experience are
lousy to outright rubbish. I buy them mainly to report on them.
Complaints are many, including color, light output, light output in
comparison to claims of light output, and a high rate of scary early
failures.

* I have seen a bad run or two of 25 watt spirals, of both GE and Lights
of America brands.

* Lights of America is a brand where I have had a disproportionate share
of early failures and other disappointments, although their spirals made
after 2001 may be as good as other brands of spirals.

* Compact fluorescents, especially of higher wattages and/or other than
non-dimmable Philips SLS types up to 23 watts, often do not do well in
small enclosed fixtures and downlights due to heat buildup.
Most commercial/institutional buildings with compact fluorescent ceiling
fixtures have different bulbs that do not include ballasts, and the
ballasts are located in the fixture usually out of view.

* Fluorescents in general, and especially ones smaller and of lower
wattage than 4-footers, tend to be uneconomical when on-time is short.
Low duty cycle makes payback of energy savings longer, and frequent
starts cause extra wear. Rated life is typically specified by the
manufacturer to be typically achieved with 3 hours average runtime per
start. I generally do not recommend compact fluorescents for motion
sensor lights, closet lights, refrigerator lights, nor for bathroom lights
that are mostly used for short trips.

Some more details in:

http://www.misty.com/~don/cfx.html

- Don Klipstein )

Thanks for the info

Lou

wrote:

On Wed, 27 Jul 2005 02:01:56 +0000 (UTC), (Don
Klipstein) wrote:

In article ,
wrote:

Has anyone noticed that Compact Florescent bulbs burn out at the same
time? The first time I thought it was a coincidense, but it just
happened again. The last time I had 2 of them in a kitchen ceiling
fixture. I installed both at the same time, same fixture, on the same
switch. One bulb burned out, a few days later the other one did.
(these were the ones that stick straight out of the base)

The explanation may be heat. A significant heatwave has
made the national news a little bit. Integral-ballast compact
fluorescents, especially 15 watts or more, often have problems with
ceiling fixtures and small enclosed fixtures and downlights. Philips SLS
non-dimmable versions up to 20 watts are better, and their 23 watt
non-dimmable version is also rated for use in recessed ceiling downlights.

Compact fluorescents do not take heat as well as incandescents, and
produce more non-radiant heat than incandescents of same wattage (but at
least normally less than incandescents of same light output). Compact
fluorescents produce little infrared, so almost all energy failing to
become visible light becomes heat in the fixture as opposed to a fair
amount materializing in the same room but outside the fixture.

Now, it's the bathroom. The bathroom has one switch that controls two
identical wall mounted fixtures on each side of the mirror. About 10
days ago I turned on the bathroom lights and one of the CF bulbs went
up in smoke (literally). There was a shower of sparks in the base of
the bulb, and a puff of smoke, which ended the bulb. I replaced that
one with a standard bulb. Today I went in the bathroom, flipped on
the lights and the other CF bulb started flashing on an off and
seconds later it got real dim and then died. (these were the twisted
type, and both were installed at the same time).

This is more than coincidense.

Maybe heat, maybe a line voltage surge from lightning damaging but not
outright killing the bulbs (line voltage surge damage is more often but
not necessarily either immediately fatal or negligible-zero).

Note: There is nothing wrong with the wiring, switch or fixtures.

I am going back to standard bulbs though. The CF bulbs do not have
anywhere near the life they state, in fact standard bulbs seem to last
much longer. For the price of these CF bulbs and their short lives, I
dont think I am saving any money. Sure they use about 60% less power,
but they cost ten times as much as regular bulbs. Besides that, after
watching that one go up in smoke, I think they are a fire hazzard.

I now see not-too-bad compact fluorescent bulbs for about $4-$5 apiece,
great ones for about $8, and frequent promotional specials at home centers
for ones at least "fair" amounting to $2 per bulb or less.

Power savings are more typically 65-70%, in good cases 75%.

Some compact fluorescents are bad and some situations do not call for
them:

* Dollar store compact fluorescents in my somewhat major experience are
lousy to outright rubbish. I buy them mainly to report on them.
Complaints are many, including color, light output, light output in
comparison to claims of light output, and a high rate of scary early
failures.

* I have seen a bad run or two of 25 watt spirals, of both GE and Lights
of America brands.

* Lights of America is a brand where I have had a disproportionate share
of early failures and other disappointments, although their spirals made
after 2001 may be as good as other brands of spirals.

* Compact fluorescents, especially of higher wattages and/or other than
non-dimmable Philips SLS types up to 23 watts, often do not do well in
small enclosed fixtures and downlights due to heat buildup.
Most commercial/institutional buildings with compact fluorescent ceiling
fixtures have different bulbs that do not include ballasts, and the
ballasts are located in the fixture usually out of view.

* Fluorescents in general, and especially ones smaller and of lower
wattage than 4-footers, tend to be uneconomical when on-time is short.
Low duty cycle makes payback of energy savings longer, and frequent
starts cause extra wear. Rated life is typically specified by the
manufacturer to be typically achieved with 3 hours average runtime per
start. I generally do not recommend compact fluorescents for motion
sensor lights, closet lights, refrigerator lights, nor for bathroom lights
that are mostly used for short trips.

Some more details in:

http://www.misty.com/~don/cfx.html

- Don Klipstein )

Well, you might have a point about the heat. It got as hot as 130 in
here last week. (No AC).

And they are GE brand as someone said, they have problems. Here I
thought GE was a good name brand ????

Good brand for locomotives, less so for cheaper stuff:-))

Lou

In article ,
wrote:

And they are GE brand as someone said, they have problems. Here I
thought GE was a good name brand ????

I have had more bad experience with GE than with Philips and Sylvania,
but less than with Lights of America.

My biggest GE gripes for compact fluorescents are for a couple
specific ones probably obsoleted or discontinued.

My biggest gripe with GE now is they are outsourcing the F8T5 (not an
actual CFL but a smaller one of the "standard" fluorescents to China and
the label only claims 5,000 hours life. The F8T5 used to be claimed to
last 7500 hours. The 5,000 hour version costs no less than these ever
did.

- Don Klipstein )

An article in papers several year ago discussed the bulb high in the
far reaches of the NY Opera House that had been burning for 40 years
and nobody had any idea where the switch was for it if there was one.

On Mon, 01 Aug 2005 02:21:26 -0500, wrote:

That 5000 hour rating means nothing as far as I am concerned.
And how is that measured? Is it supposed to be continuous use, or
ON/OFF total use? I heard that turning an indecesant bulb on and off
shortens their life. Is that also true with CFL bulbs?

In article ,
wrote:

On Fri, 29 Jul 2005 01:12:24 +0000 (UTC), (Don
Klipstein) wrote:

I snip

My biggest gripe with GE now is they are outsourcing the F8T5 (not an
actual CFL but a smaller one of the "standard" fluorescents to China and
the label only claims 5,000 hours life. The F8T5 used to be claimed to
last 7500 hours. The 5,000 hour version costs no less than these ever did.

- Don Klipstein )

And what does that 5000 or 7500 hours really mean? No one really
times them.

The "Big Three" makers actualy test their fluorescent lamps in aging
tests, turning them off and restarting them every 3 hours. At least they
did and do this for ones made in their own plants.

However, lets just make a rough estimate. I would guess
that I average 30 minutes per day of lights in the bathroom. That
figure is probably a little high for actual usage, but I do
occasionally forget to shut the light off. So, 1/2 hour per day times
365 days in a year would be approximately 183 hours. So, lets just
round this off to 200 hours, since they were left on overnight a
couple times. I installed the bulbs about 1 1/2 years ago. (2 years
at most). That means I got at most 400 hours of usage out of these GE
CFL bulbs which are rated at 5000 hours. At this rate, I did not even
get 10% of their rated life.

At my rate of usage, they SHOULD have lasted 12.5 years.

These bulbs were NOT enclosed in glass, and the base was DOWN.

I don't think I'd complain if I got even half the rated life, but I
didn't even get 10%.

That 5000 hour rating means nothing as far as I am concerned.
And how is that measured? Is it supposed to be continuous use, or
ON/OFF total use?

Usually the rating is for total "on" time with an average of 3 hours
"on" time per start.

I heard that turning an indecesant bulb on and off shortens their life.

Most incandescents do not lose much life from this, despite
incandescents usually burning out during a cold start, and despite cold
starts even visibly shaking the filament or causing the filament to
produce a "ping" sound audible at close range in a quiet room. (Some
incandescents do suffer significant filament fatigue from cold starts, but
most don't.)
What happens is that an aging filament becomes unable to survive a cold
start a little before it becomes unable to survive continuous operation.

Filament failure from a cold start is usually from a filament with a
thin spot from uneven evaporation experiencing a temperature overshoot of
the thin spot. The thin spot melts during a cold start. However, these
thin spots will only survive continuous operation for a limited amount of
time if they are already unable to survive a cold start, since once they
get that bad they are worsening at a rate that accelerates worse than
exponentially.


Is that also true with CFL bulbs?

Yes, that is true, and much more true than with incandescents. The
filaments in fluorescents do suffer actual extra wear from starting.

Some are worse than others for use in bathrooms used mainly for short
trips, although I doubt any are really good if they average only a couple
minutes runtime per start.

Worse ones for this start in these ways:

1. Blink a few times before staying on.
2. Start truly instantly.
3. Start truly instantly, although with a minor sudden jump of brightness
1/4-1/2 second later.

Better ones start in these ways:

1. Delay of a fraction of a second to a second before turning on, and
then it's on without blinking.

2. The ends glow first and then the whole thing is on, without blinking.

3. The lamp fades on in a smooth, steady but rapid process taking a
fraction of a second to maybe as long as a second.

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

I have seen in some commercial buildings restrooms with fluorescent
lights controlled by occupancy sensors. Here this makes sense since a
4-foot fluorescent only costs about a dollar when purchased several cases
at a time, and electricity savings per bulb are greater than with lower
wattages.

- Don Klipstein )

In article , nospambob wrote:

An article in papers several year ago discussed the bulb high in the
far reaches of the NY Opera House that had been burning for 40 years
and nobody had any idea where the switch was for it if there was one.

Every once in a while I hear about this lightbulb somewhere or that one
somewhere else that has been running for many decades or about a century.

Now for the kicker: How much electricity is being consumed and how much
light is the bulb producing? Answer: These super long life bulbs produce
about or less than half as much light as that produced by "standard"
incandescents of the same power consumption.

If you double your power consumption to get the same amount of light and
avoid changing lightbulbs, chances are you increase your electricity cost
more than you spent on lightbulbs.

Heck, incandescent traffic signal bulbs are only designed to last 8,000
hours. And surely labor cost of changing lightbulbs is high there.

If you have some special need for a lightbulb to last a century, get a
230 or 240 volt lightbulb and run it at 120V. At half voltage, power
consumption will be about 28-29% of rated, life will be a few thousand
times rated, and light output will be somewhere around 9% of rated.

- Don Klipstein )

wrote:
On Mon, 1 Aug 2005 15:13:33 +0000 (UTC), (Don
Klipstein) wrote:


Don

Since you seem to have much knowledge about bulbs, I got another
question. When I drop a trouble light using a standard indecescant
bulb (or even a heavy useage bulb made for trouble lights), the bulb
often gets much brighter than it was originally, but usually they burn
out shortly after. Is this extra brightness because particles fall
off the filament and it gets thinner, or is there another reason?

Thanks

It is because part of the filament has shorted across itself and reduced
the resistance and increased the current flow. As they get older the
filament may sag and with a trouble light it may be moved into different
positions so the filament can cross over itself easier than in a fixed
light.

--
Joseph Meehan

Dia duit

In article ,
wrote:

Since you seem to have much knowledge about bulbs, I got another
question. When I drop a trouble light using a standard indecescant
bulb (or even a heavy useage bulb made for trouble lights), the bulb
often gets much brighter than it was originally, but usually they burn
out shortly after. Is this extra brightness because particles fall
off the filament and it gets thinner, or is there another reason?

I have seen lightbulbs do this, although not yet seen a trouble light do
this (I am not around trouble lights in use enough to see this).

If the filament has any sharp turns, part of the filament can get
shorted by mechanical shock. This results in the remainder of the
filament getting full line voltage.
I have seen this happen with nightlight bulbs and christmas bulbs with
multiple-support filaments with sharp turns at the supports, and also with
chandelier bulbs with V-shaped filaments.

I give a possibility that other styles of filament could become
partially shorted if stretched out of shape from an impact.

I do consider it possible that if a portion of a filament gets severely
stretched with the remainder of the filament unstretched, then the
stretched portion will run cooler, have reduced resistance, and allow the
filament to get excessive current and possibly total light output could
increase. I have seen filaments unevenly stretched by impacts/shock that
were obviously very uneven in temperature.

- Don Klipstein )

wrote:
..

So, if the filament shorts or overlaps itself or any of these things,
then when the light gets brighter, I would assume the wattage also
increases, and thus the amount of electricity being used. Is this
correct?

Yes, and the lamp becomes more efficient so the amount of increased
light is more than the increased energy used. Of course you pay with
shorter lamp life.

This leads to yet another point. If the wattage does
increase, and it was a 100 watt bulb in a fixture rated at maximum
wattage 100w. Then the fixture is really overloaded, right?

Usually not. Fixtures are rated for temporary overloads.

I
suppose this could actually become a safety issue, even though the
bulbs generally burn out soon.

It could, but I would believe that the actual number where it becomes a
safety issue is very very small.

--
Joseph Meehan

Dia duit

In article ,
wrote:
On Mon, 1 Aug 2005 19:54:23 +0000 (UTC), (Don
Klipstein) wrote:

I have seen lightbulbs do this, although not yet seen a trouble light do
this (I am not around trouble lights in use enough to see this).

If the filament has any sharp turns, part of the filament can get
shorted by mechanical shock. This results in the remainder of the
filament getting full line voltage.
I have seen this happen with nightlight bulbs and christmas bulbs with
multiple-support filaments with sharp turns at the supports, and also with
chandelier bulbs with V-shaped filaments.

I give a possibility that other styles of filament could become
partially shorted if stretched out of shape from an impact.

I do consider it possible that if a portion of a filament gets severely
stretched with the remainder of the filament unstretched, then the
stretched portion will run cooler, have reduced resistance, and allow the
filament to get excessive current and possibly total light output could
increase. I have seen filaments unevenly stretched by impacts/shock that
were obviously very uneven in temperature.

So, if the filament shorts or overlaps itself or any of these things,
then when the light gets brighter, I would assume the wattage also
increases, and thus the amount of electricity being used. Is this
correct?

This is correct. Most lightbulbs that I see brightened by mechanical
shock have enough filament shorted to increase power consumption 10-20%.
If the filament is partially shorted but not stretched, it's roughly a
square root thing. Unstretched filament with more than roughly 40%
overcurrent will melt instantly.

This leads to yet another point. If the wattage does
increase, and it was a 100 watt bulb in a fixture rated at maximum
wattage 100w. Then the fixture is really overloaded, right? I
suppose this could actually become a safety issue, even though the
bulbs generally burn out soon.

If the fixture barely does not overheat with an undamaged bulb and
cannot handle the extra heat from bulbs damaged this way, then it is a
safety issue. I would think that trouble lights would be made to take
into account stretched filaments consuming extra power, whether or not
more light resulted. Now I wonder if that's wishful thinking...

- Don Klipstein )