I have a recessed light above my sink that is eating bulbs. About every
4th day the the R19 buld in the can burns out. I've checked the
connections in the switch box and replaced the switch - to no avail.
Any other suggestions?
Thx
-K2

KTwo wrote:

I have a recessed light above my sink that is eating bulbs. About every
4th day the the R19 buld in the can burns out. I've checked the
connections in the switch box and replaced the switch - to no avail. Any
other suggestions?
Thx
-K2

Sounds like an overheating problem to me.

What's the wattage of the bulbs? Is it at or below the fixture's maximum
wattage rating?

Are there vent openings in the can which are blocked by something above
the fixture?

If all else fails, replace the switch with a slide type dimmer and rig
something to keep the slider from moving all the way to "full".

HTH,

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"As long as there are final exams, there will be prayer in public
schools"

050429 2145 - KTwo posted:

I have a recessed light above my sink that is eating bulbs. About every
4th day the the R19 buld in the can burns out. I've checked the
connections in the switch box and replaced the switch - to no avail.
Any other suggestions?
Thx
-K2

Sounds like a heat problem. Try one of the new fluorescent screw-in lamps.
They run a lot cooler. One of the new "40 watt" equivalent lamps is labeled
to draw 10 watts, and after about a minute, brightens up and seems to have a
lumens equivalent of at least a 50 watt incandescent lamp.

KTwo wrote:
I have a recessed light above my sink that is eating bulbs. About
every 4th day the the R19 buld in the can burns out. I've checked the
connections in the switch box and replaced the switch - to no avail.
Any other suggestions?
Thx
-K2

I agree that heat would be the first thing I would check. I would also
check the contacts to make sure they are clean and making solid contact. I
assume there is no water getting splashed on the lamp? Vibration can also
be a killer. Does a disposal dishwasher or something above the lamp on the
next floor cause vibration?

--
Joseph Meehan

Dia duit

"indago" wrote in message
...
050429 2145 - KTwo posted:

I have a recessed light above my sink that is eating bulbs. About every
4th day the the R19 buld in the can burns out. I've checked the
connections in the switch box and replaced the switch - to no avail.
Any other suggestions?
Thx
-K2

Sounds like a heat problem. Try one of the new fluorescent screw-in
lamps.
They run a lot cooler. One of the new "40 watt" equivalent lamps is
labeled
to draw 10 watts, and after about a minute, brightens up and seems to have
a
lumens equivalent of at least a 50 watt incandescent lamp.

Have a 3-60W bulb kitchen fixture that was failing bulbs well before they
should have died--heat was the problem. Put in two 23 W new fluorescent
screw-in lamps (equiv to 100 W) and what a difference. Runs much cooler
with significantly more light. Left in one 60W bulb. Now have Lumens equal
to 260W (vs. 180) while actually using 106W. Thinking of replacing the
remaining 60W bulb except that it might be too bright now. g
MLD

On Fri, 29 Apr 2005 21:45:49 -0400, KTwo wrote:

I have a recessed light above my sink that is eating bulbs. About every
4th day the the R19 buld in the can burns out. I've checked the
connections in the switch box and replaced the switch - to no avail.
Any other suggestions?
Thx
-K2

IMHO:

Check for arcing on the bulb. You might have a bad connection with
the screwing socket.

BTW, humidity might be effecting also, so ensure the bulb is screwed
in securly.

Guessing ifyou have higher than average household voltage all your
lights would have problems not just this one.

hth,

tom @ www.ChopURL.com

indago ) said...

050429 2145 - KTwo posted:

I have a recessed light above my sink that is eating bulbs. About every
4th day the the R19 buld in the can burns out. I've checked the
connections in the switch box and replaced the switch - to no avail.
Any other suggestions?

Sounds like a heat problem. Try one of the new fluorescent screw-in lamps.
They run a lot cooler. One of the new "40 watt" equivalent lamps is labeled
to draw 10 watts, and after about a minute, brightens up and seems to have a
lumens equivalent of at least a 50 watt incandescent lamp.

There are four things that can shorten the life of a bulb:

- heat
- excessive turning on an off (manually or from a faulty switch)
- vibration
- voltage

When a bulb received more of any of these than it was designed for,
its life shortens. For instance, roughly a 5% increase in voltage will
reduce the life of a bulb by 50% (YMMV). So, a bulb rated at 1000 hours
of operation at 120 volts will only operate for 500 hours at 126 volts,
all else being equal.

Now, a bulb going after only four days (that's only 96 hours of operation,
if it was burning continuous) sounds like something is REALLY excessive,
and could even be a combination of things. In fact, a combination is
likely here since the level of excess in any one factor needed to reduce
the bulb's life to this would likely not go easily unnoticed.

Fixures have maximum bulb wattages based on their ability to properly
dissipate heat. Using a bulb of higher wattage means the fixture will
heat up too much and bulb life will be substantially reduced (in great
excess, plastic parts will melt, or fire can be an issue). Alternatively,
if vent holes are blocked or insulation is too close to the fixture,
excessive heat can build up even with the correct wattage bulb (or even
with a lower wattage bulb!)

Every time a bulb is turned on when it is cold, a great strain is placed
on it. Cold filaments have a much lower resistance, so there is a brief
surge of current greater than normally flows through it. You will likely
experience a bulb blowing more often when you turn it on than having it
just go while already lit due to this surge. Over the life of the bulb,
each turn-on takes a little away from its life. Even when hot, it is better
(for its lifespan) to leave it powered than to turn it off and on again.
A faulty switch that has poor contacts, or even a faulty socket for the
bulb can effectively be turning the bulb off and on again and thus be
shortening its lifespan.

Vibration is a killer, and one that may have the quickest effect of
killing a light bulb. If you ever experience a bulb blowing while it
has been lit for sometime (as opposed to when you flip the switch
described above), it is more likely due to vibration than to old age.
This is the one factor I would suspect if there were only a single factor
here.

I would check all of these, probably in this order: vibration, heat,
faulty switch or socket, then voltage.

--
Calvin Henry-Cotnam
"Never ascribe to malice what can equally be explained by incompetence."
- Napoleon
-------------------------------------------------------------------------
NOTE: if replying by email, remove "remove." and ".invalid"

"KTwo" wrote in message
news
I have a recessed light above my sink that is eating bulbs. About every
4th day the the R19 buld in the can burns out. I've checked the
connections in the switch box and replaced the switch - to no avail. Any
other suggestions?
Thx
-K2

Heat is seldom a factor in light bulb failure particularly if you have not
been having trouble with the lamps in that fixture previously. You may have
gotten a carton of poor-qualty bulbs, get a replacement from another store
or manufacturer to check.

The most likely cause of premature incandescent bulb failure is physical
shock or vibration. Halogen incandescent bulbs are particularly sensitive
to such failures. Put your hand on the fixture with any appliances (like a
dishwasher) in the area running. If you can feel a vibration or see the
lamp filament moving around (a slight flickering), install a bulb made for
vibration service (fan bulbs or bulbs designed for garage door openers). A
screw-in compact fluorescent lamp will also be much less sensitive to shock
or vibration.

Bad switches or loose connections don't cause standard incandescent bulbs to
fail unless the bad connection is in the lamp socket. Then an arc (very
hot) can be established which burns the bulb base or cracks the glass seal
of the bulb. You can check that easily by looking at the base and socket.
Look for any signs of melted metal or blackening.

TKM

The Real Tom wrote:
On Fri, 29 Apr 2005 21:45:49 -0400, KTwo wrote:

I have a recessed light above my sink that is eating bulbs. About
every 4th day the the R19 buld in the can burns out. I've checked
the connections in the switch box and replaced the switch - to no
avail. Any other suggestions?
Thx
-K2

IMHO:

Check for arcing on the bulb. You might have a bad connection with
the screwing socket.

BTW, humidity might be effecting also, so ensure the bulb is screwed
in securly.

Guessing ifyou have higher than average household voltage all your
lights would have problems not just this one.

If it were a floating neutral it could also cause high voltage, on one
circuit (while causing low voltage on the other) . However since we are
talking about light bulbs burning out as fast as they do, I would guess the
OP would have said something about how bright the lamps were and likely
noticed other problems.


hth,

tom @ www.ChopURL.com

--
Joseph Meehan

Dia duit

Ya know, it might be a good time to do the calculations for what
sized and wattage resistor would be needed to give a 10% drop
in the supply voltage to the bulb, since an inline dimmer runs about
14 dollars at Home Depot.

"Jeff Wisnia" wrote in message
...
If all else fails, replace the switch with a slide type dimmer and rig
something to keep the slider from moving all the way to "full".

KTwo wrote:
I have a recessed light above my sink that is eating bulbs. About every
4th day the the R19 buld in the can burns out. I've checked the
connections in the switch box and replaced the switch - to no avail. Any
other suggestions?
Thx
-K2


Probably heat build-up is killing the lamps. Try using one size smaller
wattage.

Best regards,
Bob

zxcvbob wrote:
KTwo wrote:

I have a recessed light above my sink that is eating bulbs. About
every 4th day the the R19 buld in the can burns out. I've checked the
connections in the switch box and replaced the switch - to no avail.
Any other suggestions?
Thx
-K2



Probably heat build-up is killing the lamps. Try using one size smaller
wattage.

Best regards,
Bob

Also check if there is insulation installed on top of the can, should be
a clear space above the fixture to allow for heat dissipation.
Dave

MLD wrote:


Have a 3-60W bulb kitchen fixture that was failing bulbs well before they
should have died--heat was the problem. Put in two 23 W new fluorescent
screw-in lamps (equiv to 100 W) and what a difference. Runs much cooler
with significantly more light. Left in one 60W bulb. Now have Lumens equal
to 260W (vs. 180) while actually using 106W. Thinking of replacing the
remaining 60W bulb except that it might be too bright now. g
MLD

My kitchen fixture is a 2-60W unit. Wound up replacing one, sometimes
both each month. Switched to the fluorescent lamps over a year ago.
Haven't touched it since.

Jeff Wisnia wrote:
KTwo wrote:

I have a recessed light above my sink that is eating bulbs. About
every 4th day the the R19 buld in the can burns out. I've checked the
connections in the switch box and replaced the switch - to no avail.
Any other suggestions?
Thx
-K2


Sounds like an overheating problem to me.

What's the wattage of the bulbs? Is it at or below the fixture's maximum
wattage rating?

Are there vent openings in the can which are blocked by something above
the fixture?

If all else fails, replace the switch with a slide type dimmer and rig
something to keep the slider from moving all the way to "full".

HTH,

Jeff

Jeff -

Overheating seems to be the general opinion. A number of the bulbs that
have burned out to date where left for a couple of days and only burned
out when one of my daughters turned the light off accidently when trying
to turn the disposal off (the switches are in the same box). I'll try a
smaller bulb. I don't think vibration is an issue. This light is above
by kitchen sink, so there is no garbage disposal on the floor above it.
The master bathroom is above it and I don't believe that is a large
source of vibration.

Thx

-K2

indago wrote:
050429 2145 - KTwo posted:


I have a recessed light above my sink that is eating bulbs. About every
4th day the the R19 buld in the can burns out. I've checked the
connections in the switch box and replaced the switch - to no avail.
Any other suggestions?
Thx
-K2


Sounds like a heat problem. Try one of the new fluorescent screw-in lamps.
They run a lot cooler. One of the new "40 watt" equivalent lamps is labeled
to draw 10 watts, and after about a minute, brightens up and seems to have a
lumens equivalent of at least a 50 watt incandescent lamp.

I had thought about compact flourescent (CF), but for another reason. I
was thinking that since CF don't have a filament that there's nothing
to burn out. Hadn't thought about it from the heat angle.
I've looked and have only found one source (on the web or in a store)
for CF R16 bulbs - and they're $20/ea. Ouch.
Thx
-K2

Dave Morrison wrote:
zxcvbob wrote:

KTwo wrote:

I have a recessed light above my sink that is eating bulbs. About
every 4th day the the R19 buld in the can burns out. I've checked
the connections in the switch box and replaced the switch - to no
avail. Any other suggestions?
Thx
-K2




Probably heat build-up is killing the lamps. Try using one size
smaller wattage.

Best regards,
Bob


Also check if there is insulation installed on top of the can, should be
a clear space above the fixture to allow for heat dissipation.
Dave

Unfortunately I can't do that. The can was installed when the house was
built and it's a sheetrock ceiling. I guess I could check, but that
will be a last resort, and I'll just replace the fixture while I have
the ceiling torn apart.

-K2

TKM wrote:
"KTwo" wrote in message
news
I have a recessed light above my sink that is eating bulbs. About every
4th day the the R19 buld in the can burns out. I've checked the
connections in the switch box and replaced the switch - to no avail. Any
other suggestions?
Thx
-K2


Heat is seldom a factor in light bulb failure particularly if you have not
been having trouble with the lamps in that fixture previously. You may have
gotten a carton of poor-qualty bulbs, get a replacement from another store
or manufacturer to check.

The most likely cause of premature incandescent bulb failure is physical
shock or vibration. Halogen incandescent bulbs are particularly sensitive
to such failures. Put your hand on the fixture with any appliances (like a
dishwasher) in the area running. If you can feel a vibration or see the
lamp filament moving around (a slight flickering), install a bulb made for
vibration service (fan bulbs or bulbs designed for garage door openers). A
screw-in compact fluorescent lamp will also be much less sensitive to shock
or vibration.

Bad switches or loose connections don't cause standard incandescent bulbs to
fail unless the bad connection is in the lamp socket. Then an arc (very
hot) can be established which burns the bulb base or cracks the glass seal
of the bulb. You can check that easily by looking at the base and socket.
Look for any signs of melted metal or blackening.

TKM



No sign of any arcing in socket or on the bulbs that I pull out. I'll
see what I can find for a vibration service R19 buld.
Thx
-K2

Joseph Meehan wrote:
KTwo wrote:

I have a recessed light above my sink that is eating bulbs. About
every 4th day the the R19 buld in the can burns out. I've checked the
connections in the switch box and replaced the switch - to no avail.
Any other suggestions?
Thx
-K2


I agree that heat would be the first thing I would check. I would also
check the contacts to make sure they are clean and making solid contact. I
assume there is no water getting splashed on the lamp? Vibration can also
be a killer. Does a disposal dishwasher or something above the lamp on the
next floor cause vibration?

I don't think I have a water problem. Even though the master bathroom
is directly above the light, there is no evidence on the ceiling around
the lamp or in the master bathroom of leakage. The light is above the
kitchen sink, and with 9' ceilings I'd have to have a talk with my
daughters about how the do dishes if there is water getting splashed on it.
Thx
-K2

You should be able to remove the fixture only. If it was installed
where you can't take it out by itself then it's likely installed
wrong.

Unfortunately I can't do that. The can was installed when the house was
built and it's a sheetrock ceiling. I guess I could check, but that
will be a last resort, and I'll just replace the fixture while I have
the ceiling torn apart.

-K2

Good luck.
Pictures would help to understand why you cannot remove just the
fixture.




Remove "YOURPANTIES" to reply

MUADIB®

http://www.angelfire.com/retro/sster...IN%20PAGE.html

one small step for man,.....
One giant leap for attorneys.

KTwo wrote:
....
Overheating seems to be the general opinion. A number of the bulbs that
have burned out to date where left for a couple of days and only burned
out when one of my daughters turned the light off accidently when trying
to turn the disposal off (the switches are in the same box). I'll try a
smaller bulb. I don't think vibration is an issue. This light is above
by kitchen sink, so there is no garbage disposal on the floor above it.
The master bathroom is above it and I don't believe that is a large
...

Sounds like in an enclosed area w/ not enough air movement around the
can...

I'd definitely go w/ the smaller wattage bulb and a 130V-rated would
also extend life.

If at all possible I'd try to pull the can and make sure there isn't
anything blocking the area around the fixture...

"KTwo" wrote in message
news
Jeff Wisnia wrote:
KTwo wrote:

I have a recessed light above my sink that is eating bulbs. About every
4th day the the R19 buld in the can burns out. I've checked the
connections in the switch box and replaced the switch - to no avail. Any
other suggestions?
Thx
-K2

SNIP


Jeff -

Overheating seems to be the general opinion. A number of the bulbs that
have burned out to date where left for a couple of days and only burned
out when one of my daughters turned the light off accidently when trying
to turn the disposal off (the switches are in the same box). I'll try a
smaller bulb. I don't think vibration is an issue. This light is above
by kitchen sink, so there is no garbage disposal on the floor above it.
The master bathroom is above it and I don't believe that is a large source
of vibration.

Thx

-K2

You can't rule it out just yet. One of the most troublesome lamp-failure
complaints that I ever got involved in (as a lighting engineer) involved
just such a situation. The problem was a dining room chandelier with
several lamps and it seemed to eat lamps. We tried dimmers, different
lamps, electrical checks, etc. Nothing changed. Lamps failed almost daily.
Then one evening we were sitting in the dining room and there was a great
thump overhead and one of the lamps failed. Turned out that the kids' room
was up there and it was the one of the kids jumping off the top level of the
bunk bed. Bulbs with long thin filaments are particularly sensitive to
what the lamp companies call "hot shock" and these poor lamps were getting a
regular dose.

Anybody clumping around in the bathroom upstairs on a regular basis?

TKM

"Calvin Henry-Cotnam" wrote in message
...
indago ) said...

050429 2145 - KTwo posted:

I have a recessed light above my sink that is eating bulbs. About every
4th day the the R19 buld in the can burns out. I've checked the
connections in the switch box and replaced the switch - to no avail.
Any other suggestions?

Sounds like a heat problem. Try one of the new fluorescent screw-in
lamps.
They run a lot cooler. One of the new "40 watt" equivalent lamps is
labeled
to draw 10 watts, and after about a minute, brightens up and seems to have
a
lumens equivalent of at least a 50 watt incandescent lamp.

There are four things that can shorten the life of a bulb:

- heat
- excessive turning on an off (manually or from a faulty switch)
- vibration
- voltage

When a bulb received more of any of these than it was designed for,
its life shortens. For instance, roughly a 5% increase in voltage will
reduce the life of a bulb by 50% (YMMV). So, a bulb rated at 1000 hours
of operation at 120 volts will only operate for 500 hours at 126 volts,
all else being equal.

Now, a bulb going after only four days (that's only 96 hours of operation,
if it was burning continuous) sounds like something is REALLY excessive,
and could even be a combination of things. In fact, a combination is
likely here since the level of excess in any one factor needed to reduce
the bulb's life to this would likely not go easily unnoticed.

Fixures have maximum bulb wattages based on their ability to properly
dissipate heat. Using a bulb of higher wattage means the fixture will
heat up too much and bulb life will be substantially reduced (in great
excess, plastic parts will melt, or fire can be an issue). Alternatively,
if vent holes are blocked or insulation is too close to the fixture,
excessive heat can build up even with the correct wattage bulb (or even
with a lower wattage bulb!)

Every time a bulb is turned on when it is cold, a great strain is placed
on it. Cold filaments have a much lower resistance, so there is a brief
surge of current greater than normally flows through it. You will likely
experience a bulb blowing more often when you turn it on than having it
just go while already lit due to this surge. Over the life of the bulb,
each turn-on takes a little away from its life. Even when hot, it is
better
(for its lifespan) to leave it powered than to turn it off and on again.
A faulty switch that has poor contacts, or even a faulty socket for the
bulb can effectively be turning the bulb off and on again and thus be
shortening its lifespan.

Vibration is a killer, and one that may have the quickest effect of
killing a light bulb. If you ever experience a bulb blowing while it
has been lit for sometime (as opposed to when you flip the switch
described above), it is more likely due to vibration than to old age.
This is the one factor I would suspect if there were only a single factor
here.

I would check all of these, probably in this order: vibration, heat,
faulty switch or socket, then voltage.

--
Calvin Henry-Cotnam
"Never ascribe to malice what can equally be explained by incompetence."
- Napoleon
-------------------------------------------------------------------------
NOTE: if replying by email, remove "remove." and ".invalid"

Your voltage and vibration causes for unusually short incandescent bulb life
are correct; but heat and on/off cycles are not. The little bit of extra
heat in a tight fixture makes no difference to a bulb filament which is
operating at 3373 degrees C. For heat to affect bulb life, you have to
either have enough heat to melt the glass, crack the internal glass seal or
destroy the lamp basing cement. Think about incandescent bulbs in ovens and
other high-temperature applications. There's nothing special about them.

On/off operation might affect bulb life a bit when the bulb is old; but not
when the bulb is new. If on/off made a difference, we wouldn't see flashing
sign lamps on theater marquees.

TKM

snip

Your voltage and vibration causes for unusually short incandescent bulb
life are correct; but heat and on/off cycles are not. The little bit of
extra heat in a tight fixture makes no difference to a bulb filament which
is operating at 3373 degrees C. For heat to affect bulb life, you have to
either have enough heat to melt the glass, crack the internal glass seal
or destroy the lamp basing cement. Think about incandescent bulbs in
ovens and other high-temperature applications. There's nothing special
about them.

On/off operation might affect bulb life a bit when the bulb is old; but
not when the bulb is new. If on/off made a difference, we wouldn't see
flashing sign lamps on theater marquees.

....but a bulb that is never shut off will last longer than a bulb going off
and on. All my bulbs fail when turned on.

If a bulb is never cycled, its filament can get much weaker before it fails
because it doesn't have to withstand any shock of heating or cooling.

"Noozer" wrote in message
news:OkTce.1178374$Xk.570089@pd7tw3no...
snip

Your voltage and vibration causes for unusually short incandescent bulb
life are correct; but heat and on/off cycles are not. The little bit of
extra heat in a tight fixture makes no difference to a bulb filament
which is operating at 3373 degrees C. For heat to affect bulb life, you
have to either have enough heat to melt the glass, crack the internal
glass seal or destroy the lamp basing cement. Think about incandescent
bulbs in ovens and other high-temperature applications. There's nothing
special about them.

On/off operation might affect bulb life a bit when the bulb is old; but
not when the bulb is new. If on/off made a difference, we wouldn't see
flashing sign lamps on theater marquees.

...but a bulb that is never shut off will last longer than a bulb going
off and on. All my bulbs fail when turned on.

If a bulb is never cycled, its filament can get much weaker before it
fails because it doesn't have to withstand any shock of heating or
cooling.
According to light bulb test data in the lighting literature, turning a
bulb on and off has no effect during most of the bulb life. It is only when
the bulb gets older and the filament starts to crystallize and get brittle
that on/off makes a difference and why bulbs often fail when turned on due
to the current surge and rapid heating. Old bulbs are also more sensitive
to shock and vibration -- the brittle filament again.

Tests with bulbs left on and with bulbs on/off cycled when corrected for
burning time showed little difference in life.

The above are long-held notions, maybe "urban legends", but the data don't
confirm that heat or on/off cycling shorten incandescent bulb life. The
references are in the Illuminating Engineering Society of North America
Handbook, 9th. Ed. Chapter 6.

TKM

MUADIB® wrote:
You should be able to remove the fixture only. If it was installed
where you can't take it out by itself then it's likely installed
wrong.


Unfortunately I can't do that. The can was installed when the house was
built and it's a sheetrock ceiling. I guess I could check, but that
will be a last resort, and I'll just replace the fixture while I have
the ceiling torn apart.


Pictures would help to understand why you cannot remove just the
fixture.

I pulled the fixture part down, but not out. The fixture (the part the
light bulb screws into, right?) is wired directly to the junction box on
the can somewhere in the ceiling. The wires leave the fixture and go
out of the can to the junction box. The only thing on the wires was a
piece of small black plastic (1/4" by 1/2") clamped on the hot wire.
Couldn't see any writing on it.

I did go to Home Depot and got a 30W bulb to replace the long string of
recently defunct 50W bulbs. The can does say that it will take a 50W R20.

-K2

And whose fault is that?
How often did you say they had to be replaced? ;-Þ

"KTwo" wrote in message
news
The master bathroom is above it and I don't believe that is a large
source of vibration.

Thx

-K2

In article , KTwo wrote:

I had thought about compact flourescent (CF), but for another reason. I
was thinking that since CF don't have a filament that there's nothing
to burn out.

Doesn't mean they last forever, though. :-) But they *do* have a much longer
life than incandescent bulbs.

Hadn't thought about it from the heat angle.

Yep. Same light output, with a *lot* less heat - which means that they use a
lot less electricity, too, about 75% less.

I've looked and have only found one source (on the web or in a store)
for CF R16 bulbs - and they're $20/ea. Ouch.

The lifespan is going to be about five or six times as long as an incandescent
lamp. If you're paying more than $4 each for your incandescents, the CF is a
better buy *solely* on the basis of the cost of the lamps. When you figure in
the savings in electricity costs over the life of the bulb, the CF is a *huge*
money saver.

--
Regards,
Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?

On Sat, 30 Apr 2005 14:42:12 -0400, KTwo wrote:

The master bathroom is above it and I don't believe that is a large
source of vibration.

Thx

-K2


I'm sorry.

Steve B.

Michael Baugh wrote:
And whose fault is that?
How often did you say they had to be replaced? ;-Þ

"KTwo" wrote in message
news
The master bathroom is above it and I don't believe that is a large
source of vibration.

Thx

-K2



Some of them die in three or four days. They actually burn out faster
than we can go through AA batteries! ;-)

TKM ) said...

For heat to affect bulb life, you have to
either have enough heat to melt the glass, crack the internal glass seal or
destroy the lamp basing cement. Think about incandescent bulbs in ovens and
other high-temperature applications.

Then why are special bulbs manufactured for those applications?

Yes, bulb filaments operate at very high temperatures, but the overall
heat buildup for the bulb as a whole has a design limit. Exceed that limit,
whithout exceeding limits that would cause a fire or do other damage, and
you will see a decrease in bulb life.

On/off operation might affect bulb life a bit when the bulb is old; but not
when the bulb is new.

It is stress, but generally has little effect on a newer bulb.

If on/off made a difference, we wouldn't see flashing
sign lamps on theater marquees.

True, but what is the total hours of operation of these lamps and how
does this compare to that of a bulb that is just left on?


All that said, a main point in my original post was that with the exception
of vibrations, it is not likely that any one factor could reduce the life
of a bulb nearly as much as the original poster was experiencing.

--
Calvin Henry-Cotnam
"Never ascribe to malice what can equally be explained by incompetence."
- Napoleon
-------------------------------------------------------------------------
NOTE: if replying by email, remove "remove." and ".invalid"

"Calvin Henry-Cotnam" wrote in message
...
TKM ) said...

For heat to affect bulb life, you have to
either have enough heat to melt the glass, crack the internal glass seal
or
destroy the lamp basing cement. Think about incandescent bulbs in ovens
and
other high-temperature applications.

Then why are special bulbs manufactured for those applications?

The only thing different about oven bulbs is that they have high-temperature
basing cement so the base won't come apart and stick in the socket when the
bulb is replaced. They may also have a a smaller glass envelope than
similar wattage lamps made for general lighting service.

Yes, bulb filaments operate at very high temperatures, but the overall
heat buildup for the bulb as a whole has a design limit. Exceed that
limit,
whithout exceeding limits that would cause a fire or do other damage, and
you will see a decrease in bulb life.

As I said, that's a widely-held opinion, but the tests reported in lighting
journals, papers, etc. don't confirm that bulb life is reduced until the
glass softens or a seal cracks and lets in air. That's not likely to happen
in a situation where the fixture just seems to be hot to the touch even if
there's some smoking or deterioration of the fixture finishes.

On/off operation might affect bulb life a bit when the bulb is old; but
not
when the bulb is new.

It is stress, but generally has little effect on a newer bulb.

If on/off made a difference, we wouldn't see flashing
sign lamps on theater marquees.

True, but what is the total hours of operation of these lamps and how
does this compare to that of a bulb that is just left on?

That's with the total "on" time taken into account.

All that said, a main point in my original post was that with the
exception
of vibrations, it is not likely that any one factor could reduce the life
of a bulb nearly as much as the original poster was experiencing.

Agree. There's something else going on here. It sure sounds like poor lamp
quality and I'd like to see what happens when the OP tries another brand or
type of bulb.

TKM

"KTwo" wrote in message
...
MUADIB® wrote:
You should be able to remove the fixture only. If it was installed
where you can't take it out by itself then it's likely installed
wrong.


Unfortunately I can't do that. The can was installed when the house was
built and it's a sheetrock ceiling. I guess I could check, but that will
be a last resort, and I'll just replace the fixture while I have the
ceiling torn apart.


Pictures would help to understand why you cannot remove just the
fixture.

I pulled the fixture part down, but not out. The fixture (the part the
light bulb screws into, right?) is wired directly to the junction box on
the can somewhere in the ceiling. The wires leave the fixture and go out
of the can to the junction box. The only thing on the wires was a piece
of small black plastic (1/4" by 1/2") clamped on the hot wire. Couldn't
see any writing on it.

I did go to Home Depot and got a 30W bulb to replace the long string of
recently defunct 50W bulbs. The can does say that it will take a 50W R20.

-K2

Do let us know how the 30W is doing. Also, try the 50W Halogen PAR (flood)
lamp. HD has those too. If you did indeed get some faulty 50W R20s, I hope
that you saved them and the packaging so you can take them back. If HD
won't do anything, send them to the manufacturer. Likely you will at least
get replacements and maybe a few extra.

TKM

In article , indago wrote:
050429 2145 - KTwo posted:

I have a recessed light above my sink that is eating bulbs. About every
4th day the the R19 buld in the can burns out. I've checked the
connections in the switch box and replaced the switch - to no avail.
Any other suggestions?
Thx
-K2

Sounds like a heat problem. Try one of the new fluorescent screw-in lamps.
They run a lot cooler. One of the new "40 watt" equivalent lamps is labeled
to draw 10 watts, and after about a minute, brightens up and seems to have a
lumens equivalent of at least a 50 watt incandescent lamp.

Please note some things about using compact fluorescents in recessed
ceiling fixtures, downlights, etc:

1. Compact fluorescents produce more non-radiant heat than incandescents
of similar wattage, although usually less than that of incandescents of
same light output.
For example, a 42 watt compact fluorescent makes the fixture hotter than
a 60 watt incandescent does, although not as hot as a 150 watt
incandescent that the 42 watt CF approximates in light output.

2. Compact fluorescents do not take temperature extremes as well as
incandescents do. Excessive heat can reduce life, dim them, and adversely
affect their color and color rendering properties.

Many compact fluorescents are not even rated for use in recessed ceiling
fixtures.
Two that I have known to be rated for use in recessed ceiling fixtures
are the Philips SLS 15 and 20 watt, and notably not higher wattages of
this product line. (It's been a few years since I last checked.) The 15
and 20 watt SLS are available with snap-on R30 (3.75 inch diameter) and
R40 (5 inch diameter) snap-on reflectors. The R40 version is not quite as
good optically as an incandescent floodlight, and the R30 version is more
severely compromised.
The 20 watt has raw light output about that of 75 watt incandescents,
although in floodlight duty with the R40 reflector may be closer to 60
watt unless the lamp count is large enough that you benefit from beams
spreading into each other. The 15 watt version has raw light output about
that of 60 watt incandescent.

As for other compact fluorescents in heat buildup situations: It
appears to me that you usually get away with it with wattages up to 23
watts, and not with wattages of 24 watts or more. (For one thing, the 23
watt version of spiral units appears to me an improved version of 24 and
25 watt ones that did not do as well before.) I do expect that 26 watt
and higher wattages will run into more heat trouble than wattages 23 watts
or less. I do expect that most models 13 watts or less (with light
output at most on a good day about that of a 60 watt "standard"
incandescent) will run reasonably well in fixtures that accumulate heat.

My compact fluorescent "top page" is http://www.misty.com/~don/cfx.html

- Don Klipstein )

TKM wrote:


Do let us know how the 30W is doing. Also, try the 50W Halogen PAR (flood)
lamp. HD has those too. If you did indeed get some faulty 50W R20s, I hope
that you saved them and the packaging so you can take them back. If HD
won't do anything, send them to the manufacturer. Likely you will at least
get replacements and maybe a few extra.

TKM


Well, it's been 24 hours and a couple of off-on cycles and the 30W bulb
still works. I may not seem like much but it has exceeded the lifespan
of some other bulbs.

Bad bulbs are a possibility as I think the latest string of bulbs was a
6 pack from Costco. But they were Sylvania, not some no-name brand. If
the 30W doesn't make muster then I'll look at a halogen PAR.

Thx
-K2

In article , KTwo wrote:
indago wrote:
050429 2145 - KTwo posted:


I have a recessed light above my sink that is eating bulbs. About every
4th day the the R19 buld in the can burns out. I've checked the
connections in the switch box and replaced the switch - to no avail.
Any other suggestions?
Thx
-K2


Sounds like a heat problem. Try one of the new fluorescent screw-in lamps.
They run a lot cooler. One of the new "40 watt" equivalent lamps is labeled
to draw 10 watts, and after about a minute, brightens up and seems to have a
lumens equivalent of at least a 50 watt incandescent lamp.

I had thought about compact flourescent (CF), but for another reason. I
was thinking that since CF don't have a filament that there's nothing
to burn out. Hadn't thought about it from the heat angle.
I've looked and have only found one source (on the web or in a store)
for CF R16 bulbs - and they're $20/ea. Ouch.

How about "reflector flood" compact fluorescents of size larger than R16
if they fit in your fixture?

The number after the R (or other bulb shape designation) in the USA
usually means diameter in 1/8's of an inch. R16 is 2 inches in diameter,
and R40 is 5 inches in diameter.

Look for larger sizes should they fit. Since the tubing of a compact
fluorescent is bigger than an incandescent filament, you need a larger
reflector to get the same optical properties. I do suggest seeing if the
largest reflector size reflectorized compact fluorescent works for you.

- Don Klipstein )

In article , The Real Tom wrote:
On Fri, 29 Apr 2005 21:45:49 -0400, KTwo wrote:

I have a recessed light above my sink that is eating bulbs. About every
4th day the the R19 buld in the can burns out. I've checked the
connections in the switch box and replaced the switch - to no avail.
Any other suggestions?
Thx
-K2

IMHO:

Check for arcing on the bulb. You might have a bad connection with
the screwing socket.

BTW, humidity might be effecting also, so ensure the bulb is screwed
in securly.

Watch for poor contact in sockets that have previously experienced
overtightening!

I remember seeing somewhere a recommendation to not screw in a lightbulb
to an extent beyond 1/8 of a turn past the point of feeling like it made
contact. Tightening past that point supposedly risks bending down the
center contact in the socket.

Should you have a socket "damaged" by prior overtightening, then WITH
POWER OFF, preferably with the appropriate breaker off:
Pry the "cenhter contact" in the socket upwards with a screwdriver or
whatever with just enough force to make it a little higher than it was
recently, and "pat it down" with a light touch to make sure you actually
bent it a little upwards.

- Don Klipstein )

In article , KTwo wrote:
Dave Morrison wrote:

Also check if there is insulation installed on top of the can, should be
a clear space above the fixture to allow for heat dissipation.
Dave

Unfortunately I can't do that. The can was installed when the house was
built and it's a sheetrock ceiling. I guess I could check, but that
will be a last resort, and I'll just replace the fixture while I have
the ceiling torn apart.

The fixture should be removable enough to check for being covered by
heat insulation - a major no-no!

- Don Klipstein )

"KTwo" wrote in message
...
TKM wrote:


Do let us know how the 30W is doing. Also, try the 50W Halogen PAR
(flood) lamp. HD has those too. If you did indeed get some faulty 50W
R20s, I hope that you saved them and the packaging so you can take them
back. If HD won't do anything, send them to the manufacturer. Likely
you will at least get replacements and maybe a few extra.

TKM
Well, it's been 24 hours and a couple of off-on cycles and the 30W bulb
still works. I may not seem like much but it has exceeded the lifespan of
some other bulbs.

Bad bulbs are a possibility as I think the latest string of bulbs was a 6
pack from Costco. But they were Sylvania, not some no-name brand. If the
30W doesn't make muster then I'll look at a halogen PAR.

Thx
-K2

The trouble is that lamps are made on such fast machinery today that if a
machine gets out of adjustment, many bad lamps can be made very quickly. The
quality manufacturers constantly test their products on the manufacturing
line, so the chance of bad lamps getting out the door is small; but it does
happen. At least with Sylvania lamps you'll likely get a response and
some replacements if indeed the lamps are bad.

TKM

Good answer. I suggest the Hitachi unit.

"KTwo" wrote in message
...
Michael Baugh wrote:
And whose fault is that?
How often did you say they had to be replaced? ;-Þ

"KTwo" wrote in message
news
Some of them die in three or four days. They actually burn out faster
than we can go through AA batteries! ;-)