The ceiling fixtures in our house all have labels indicating the maximum
wattage (incandescent) bulb to place in the fixture.

I assume this is a heat-based limit...
of course it is. Do you think the actual light causes the fixture to catch
fire?

Although heat may and probably is the issue, over wattage through
current draw certainly could become a problem.

wrote:
The ceiling fixtures in our house all have labels indicating the maximum
wattage (incandescent) bulb to place in the fixture.
I assume this is a heat-based limit...
of course it is. Do you think the actual light causes the fixture to catch
fire?

Although heat may and probably is the issue, over wattage through
current draw certainly could become a problem.

It *could...* if CFLs were made that drew over 60W. I haven't seen one
yet... heck, even a 48" T12 only draws 40W a tube.

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

Nate Nagel wrote:
wrote:
The ceiling fixtures in our house all have labels indicating the
maximum wattage (incandescent) bulb to place in the fixture.
I assume this is a heat-based limit...
of course it is. Do you think the actual light causes the fixture to
catch
fire?

Although heat may and probably is the issue, over wattage through
current draw certainly could become a problem.

It *could...* if CFLs were made that drew over 60W. I haven't seen one
yet... heck, even a 48" T12 only draws 40W a tube.

nate


Indeed...I figure as long as I compare apples to apples (watts to
watts), the issue if illumination values doesn't matter..

Thanks for the responses.

ropeyarn wrote:
Nate Nagel wrote:
wrote:
The ceiling fixtures in our house all have labels indicating the
maximum wattage (incandescent) bulb to place in the fixture.
I assume this is a heat-based limit...
of course it is. Do you think the actual light causes the fixture
to catch
fire?

Although heat may and probably is the issue, over wattage through
current draw certainly could become a problem.

It *could...* if CFLs were made that drew over 60W. I haven't seen
one yet... heck, even a 48" T12 only draws 40W a tube.

nate


Indeed...I figure as long as I compare apples to apples (watts to
watts), the issue if illumination values doesn't matter..

Thanks for the responses.

I like to buy on a high ratio of lumens to watts. Even pre cfl, I
observed that some long life incandescents gave less light for the same
wattage.

Frank wrote:

I like to buy on a high ratio of lumens to watts. Even pre cfl, I
observed that some long life incandescents gave less light for the
same wattage.

Yeah. Some charitable organizations used to sell "long life bulbs" and help
the victims of Chastic Fibrosis (a disease usually found in foxes).

Turns out, the filaments were 10d nails or some such.

ropeyarn wrote:
Nate Nagel wrote:
wrote:
The ceiling fixtures in our house all have labels indicating the
maximum wattage (incandescent) bulb to place in the fixture.
I assume this is a heat-based limit...
of course it is. Do you think the actual light causes the fixture
to catch
fire?

Although heat may and probably is the issue, over wattage through
current draw certainly could become a problem.

It *could...* if CFLs were made that drew over 60W. I haven't seen
one yet... heck, even a 48" T12 only draws 40W a tube.

nate


Indeed...I figure as long as I compare apples to apples (watts to
watts), the issue if illumination values doesn't matter..

Thanks for the responses.

Well... I don't know whether a 15W CFL produces more or less heat than a
15W incandescent. I ASSume less, but I don't know how much less. That
said, the largest CFL I've seen is 23W and we're talking about 60W light
fixtures, so I don't know that it matters all that much.

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

Nate Nagel wrote:

Well... I don't know whether a 15W CFL produces more or less heat than a
15W incandescent. I ASSume less, but I don't know how much less. That
said, the largest CFL I've seen is 23W and we're talking about 60W light
fixtures, so I don't know that it matters all that much.

There's basic physics at work here. Watts are a measure of electricity
consumption, not light output. Heat produced is completely based on watts
consumed. Incandescent bulbs are essentially electric heaters that happen to
throw out a small amount of light. You just need to make sure you are comparing
the actual current draw and not the equivilent light output.

A modern "60w" CFL is using less that 15w of electricity, the "75w" draw about
18w, and "100w" use about 23w actual.

In article , Robert Neville wrote:
Nate Nagel wrote:

Well... I don't know whether a 15W CFL produces more or less heat than a
15W incandescent. I ASSume less, but I don't know how much less. That
said, the largest CFL I've seen is 23W and we're talking about 60W light
fixtures, so I don't know that it matters all that much.

There's basic physics at work here. Watts are a measure of electricity
consumption, not light output. Heat produced is completely based on watts
consumed. Incandescent bulbs are essentially electric heaters that happen to
throw out a small amount of light. You just need to make sure you are comparing
the actual current draw and not the equivilent light output.

A modern "60w" CFL is using less that 15w of electricity, the "75w" draw about
18w, and "100w" use about 23w actual.

I consider at least some of this optimistic.

A "standard" 100W 120V A19 incandescent rated to last 750 hours and made
by one of the "Big 3" (GE, Sylvania or Philips) and with "CC-8" style
filament is usually rated to produce 1710 lumens, sometimes 1730 or 1750.

CFLs getting that high tend to have wattage at least 26 watts, though I
am aware of a non-spiral one by Philips rated to achieve that with 25
watts.

With a couple thousand hours of aging and/or even only moderately
non-optimum temperature, 30 watt spirals hardly get past 1750 lumens.

At least a 30 watt spiral will not overheat a fixture rated for 60 watt
incandescents - but it can easily overheat itself in small enclosed
fixtures and downlights.
Safer is 23 watts - "a bit dimmish for 100 watt incandescent
equivalence" is what I would call those. After a few thousand hours of
aging and/or off-optimum temperature, I would like to call those
equivalent to 75 watt "standard" 120V incandescents (which traditionally
produce 1190, sometimes 1210 lumens IIRC). 23 watt CFLs nowadays are
indeed rated to produce 1600 lumens right after they have gotten past the
first 100 operating hours.

Also, I tend to see a CFL of usual 2700K color temp. rating a few
percent dimmer than an incandescent of same lumens due to the
scotopic/photopic issue, which I find a bit significant in most home
lighting. I would not counter that with color temps. above 3500 K - color
temp. above 3500 K easily appears "dreary gray" in most home lighting.

What I like to do is consider 13-15 watt CFLs to be comparable to
"longlife" and "industrial service" 60 watt incandescents, 18-20 watt CFLs
to be comparable to 1,000 hour 60 watt incandescents, and 23 watt CFLs to
be comparable to 75 watt 750 hour incandescents.

- Don Klipstein )

In article , Nate Nagel wrote:
ropeyarn wrote:
Nate Nagel wrote:
wrote:
The ceiling fixtures in our house all have labels indicating the
maximum wattage (incandescent) bulb to place in the fixture.
I assume this is a heat-based limit...
of course it is. Do you think the actual light causes the fixture
to catch
fire?

Although heat may and probably is the issue, over wattage through
current draw certainly could become a problem.

It *could...* if CFLs were made that drew over 60W. I haven't seen
one yet... heck, even a 48" T12 only draws 40W a tube.

Indeed...I figure as long as I compare apples to apples (watts to
watts), the issue if illumination values doesn't matter..

Thanks for the responses.

Well... I don't know whether a 15W CFL produces more or less heat than a
15W incandescent. I ASSume less, but I don't know how much less. That
said, the largest CFL I've seen is 23W and we're talking about 60W light
fixtures, so I don't know that it matters all that much.

A 15 watt CFL will heat the fixture much more than a 15 watt
incandescent despite the CFL producing more light.

I see plenty of 26 watt CFLs and a few 30 watt ones - should not
overheat a fixture rated for 60 watt incandescents, but could overheat
themselves if the fixture is a small enclosed fixture or a downlight.
I see a few 42 watt ones (roughly / almost 150 watt incandescent
equivalence) - and I have one test result of one of those heating a
fixture a little more than a 60 watt incandescent does (due to a higher
percentage of its output being non-radiant heat as opposed to infrared).

23 watt ones will not overheat the fixture and will usually not overheat
themselves. Some fixtures may cause some but not all CFLs of wattages as
low as 14 watts to overheat.

- Don Klipstein )

In article , ropeyarn wrote:
Nate Nagel wrote:
wrote:
The ceiling fixtures in our house all have labels indicating the
maximum wattage (incandescent) bulb to place in the fixture.
I assume this is a heat-based limit...
of course it is. Do you think the actual light causes the fixture to
catch
fire?

Although heat may and probably is the issue, over wattage through
current draw certainly could become a problem.

It *could...* if CFLs were made that drew over 60W. I haven't seen one
yet... heck, even a 48" T12 only draws 40W a tube.

nate


Indeed...I figure as long as I compare apples to apples (watts to
watts), the issue if illumination values doesn't matter..

Thanks for the responses.

I would multiply CFL wattage by 1.5 (maybe as much as 1.75) for fixture
heating effect in comparison to incandescent, since incandescents produce
a lot of infrared. Most of that infrared becomes heat - in the room but
not in the fixture. CFLs produce little infrared, but mostly non-radiant
heat and visible light.

- Don Klipstein )

Don Klipstein wrote:
In article , ropeyarn wrote:
Nate Nagel wrote:
wrote:
The ceiling fixtures in our house all have labels indicating the
maximum wattage (incandescent) bulb to place in the fixture.
I assume this is a heat-based limit...
of course it is. Do you think the actual light causes the fixture to
catch
fire?
Although heat may and probably is the issue, over wattage through
current draw certainly could become a problem.
It *could...* if CFLs were made that drew over 60W. I haven't seen one
yet... heck, even a 48" T12 only draws 40W a tube.

nate

Indeed...I figure as long as I compare apples to apples (watts to
watts), the issue if illumination values doesn't matter..

Thanks for the responses.

I would multiply CFL wattage by 1.5 (maybe as much as 1.75) for fixture
heating effect in comparison to incandescent, since incandescents produce
a lot of infrared. Most of that infrared becomes heat - in the room but
not in the fixture. CFLs produce little infrared, but mostly non-radiant
heat and visible light.

- Don Klipstein )

Even at 1.5:
I can rest easy :-)

Thanks

On Mon, 19 Jan 2009 16:38:41 -0500, Nate Nagel
wrote:

wrote:
The ceiling fixtures in our house all have labels indicating the maximum
wattage (incandescent) bulb to place in the fixture.
I assume this is a heat-based limit...
of course it is. Do you think the actual light causes the fixture to catch
fire?

Although heat may and probably is the issue, over wattage through
current draw certainly could become a problem.

It *could...* if CFLs were made that drew over 60W. I haven't seen one
yet... heck, even a 48" T12 only draws 40W a tube.

nate

The discussion is about fixtures, and their heat rating, not
necessarily CFL's.

On Mon, 19 Jan 2009 15:59:38 -0500, wrote:

The ceiling fixtures in our house all have labels indicating the maximum
wattage (incandescent) bulb to place in the fixture.

I assume this is a heat-based limit...
of course it is. Do you think the actual light causes the fixture to catch
fire?

Although heat may and probably is the issue, over wattage through
current draw certainly could become a problem.

A bulb that draws 25W to produce the light of a 75W incadescent bulb
isn't going to overtax a fixture designed for 75W.

On Mon, 19 Jan 2009 19:23:56 -0600, AZ Nomad
wrote:

On Mon, 19 Jan 2009 15:59:38 -0500, wrote:

The ceiling fixtures in our house all have labels indicating the maximum
wattage (incandescent) bulb to place in the fixture.

I assume this is a heat-based limit...
of course it is. Do you think the actual light causes the fixture to catch
fire?

Although heat may and probably is the issue, over wattage through
current draw certainly could become a problem.

A bulb that draws 25W to produce the light of a 75W incadescent bulb
isn't going to overtax a fixture designed for 75W.

Correct you are, but what happens to a fixture that is rated for
a 100 watt incandescent bulb when you use it for something other
than lighting? Are you saying that as long as you don't develop
100 watts of heat then the fixture will be just fine?

wrote:
On Mon, 19 Jan 2009 19:23:56 -0600, AZ Nomad
wrote:

On Mon, 19 Jan 2009 15:59:38 -0500, wrote:

The ceiling fixtures in our house all have labels indicating the maximum
wattage (incandescent) bulb to place in the fixture.
I assume this is a heat-based limit...
of course it is. Do you think the actual light causes the fixture to catch
fire?
Although heat may and probably is the issue, over wattage through
current draw certainly could become a problem.
A bulb that draws 25W to produce the light of a 75W incadescent bulb
isn't going to overtax a fixture designed for 75W.

Correct you are, but what happens to a fixture that is rated for
a 100 watt incandescent bulb when you use it for something other
than lighting? Are you saying that as long as you don't develop
100 watts of heat then the fixture will be just fine?

Yes, so long as you aren't actually drawing more than 100W.

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

On Mon, 19 Jan 2009 20:40:19 -0500, Nate Nagel
Correct you are, but what happens to a fixture that is rated for
a 100 watt incandescent bulb when you use it for something other
than lighting? Are you saying that as long as you don't develop
100 watts of heat then the fixture will be just fine?

Yes, so long as you aren't actually drawing more than 100W.

nate

So a fixture that is rated for a 100 watt incandescent that would
normally draw less than 1 amp can draw 20 amps as long as there
is no heat involved?

On Mon, 19 Jan 2009 20:56:45 -0500, wrote:
On Mon, 19 Jan 2009 20:40:19 -0500, Nate Nagel
Correct you are, but what happens to a fixture that is rated for
a 100 watt incandescent bulb when you use it for something other
than lighting? Are you saying that as long as you don't develop
100 watts of heat then the fixture will be just fine?

Yes, so long as you aren't actually drawing more than 100W.

nate

So a fixture that is rated for a 100 watt incandescent that would
normally draw less than 1 amp can draw 20 amps as long as there
is no heat involved?

No. Where'd you get that insane idea?

wrote:
On Mon, 19 Jan 2009 20:40:19 -0500, Nate Nagel
Correct you are, but what happens to a fixture that is rated for
a 100 watt incandescent bulb when you use it for something other
than lighting? Are you saying that as long as you don't develop
100 watts of heat then the fixture will be just fine?
Yes, so long as you aren't actually drawing more than 100W.

nate

So a fixture that is rated for a 100 watt incandescent that would
normally draw less than 1 amp can draw 20 amps as long as there
is no heat involved?

Did you read the words that I typed?

I'm guessing... no.

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

wrote:

So a fixture that is rated for a 100 watt incandescent that would
normally draw less than 1 amp can draw 20 amps as long as there
is no heat involved?

Thats a nonsensical question. If you are drawing 20A of 120v AC electricity, you
are using 2400w of electricity*. And there will always be heat involved.

*Assuming the power factor is 1, which for light bulbs and most residential
useage, is true.

On Mon, 19 Jan 2009 19:34:25 -0700, Robert Neville wrote:
wrote:

So a fixture that is rated for a 100 watt incandescent that would
normally draw less than 1 amp can draw 20 amps as long as there
is no heat involved?

Thats a nonsensical question. If you are drawing 20A of 120v AC electricity, you
are using 2400w of electricity*. And there will always be heat involved.

*Assuming the power factor is 1, which for light bulbs and most residential
useage, is true.

time to killfile the clown. tnom isn't interested in any answers, but only
in participating in a perpetual argument.

On Mon, 19 Jan 2009 19:34:25 -0700, Robert Neville
wrote:

wrote:

So a fixture that is rated for a 100 watt incandescent that would
normally draw less than 1 amp can draw 20 amps as long as there
is no heat involved?

Thats a nonsensical question. If you are drawing 20A of 120v AC electricity, you
are using 2400w of electricity*. And there will always be heat involved.

So in all instances 2400 watts of electricity will create 2400 watts
of heat? Couldn't 2400 watts of electricity only create 100 watts of
heat?

Nate Nagel wrote:

wrote:

On Mon, 19 Jan 2009 19:23:56 -0600, AZ Nomad
wrote:

On Mon, 19 Jan 2009 15:59:38 -0500,
wrote:

The ceiling fixtures in our house all have labels indicating the
maximum wattage (incandescent) bulb to place in the fixture.
I assume this is a heat-based limit...

of course it is. Do you think the actual light causes the fixture
to catch
fire?

Although heat may and probably is the issue, over wattage through
current draw certainly could become a problem.

A bulb that draws 25W to produce the light of a 75W incadescent bulb
isn't going to overtax a fixture designed for 75W.


Correct you are, but what happens to a fixture that is rated for a 100
watt incandescent bulb when you use it for something other than
lighting? Are you saying that as long as you don't develop 100 watts
of heat then the fixture will be just fine?


Yes, so long as you aren't actually drawing more than 100W.

nate

I think perhaps his point is how the power factor can affect the current
vs watt relationship.

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

On Mon, 19 Jan 2009 19:57:12 -0600, CJT wrote:

Nate Nagel wrote:

wrote:

On Mon, 19 Jan 2009 19:23:56 -0600, AZ Nomad
wrote:

On Mon, 19 Jan 2009 15:59:38 -0500,
wrote:

Correct you are, but what happens to a fixture that is rated for a 100
watt incandescent bulb when you use it for something other than
lighting? Are you saying that as long as you don't develop 100 watts
of heat then the fixture will be just fine?


Yes, so long as you aren't actually drawing more than 100W.

nate

I think perhaps his point is how the power factor can affect the current
vs watt relationship.

My point is that a light fixture rated for a 100 watt incandescent
only has to be robust enough to support the current of that same bulb.
1 amp.

wrote:
On Mon, 19 Jan 2009 19:57:12 -0600, CJT wrote:

Nate Nagel wrote:

wrote:

On Mon, 19 Jan 2009 19:23:56 -0600, AZ Nomad
wrote:

On Mon, 19 Jan 2009 15:59:38 -0500,
wrote:

Correct you are, but what happens to a fixture that is rated for a 100
watt incandescent bulb when you use it for something other than
lighting? Are you saying that as long as you don't develop 100 watts
of heat then the fixture will be just fine?

Yes, so long as you aren't actually drawing more than 100W.

nate

I think perhaps his point is how the power factor can affect the current
vs watt relationship.

My point is that a light fixture rated for a 100 watt incandescent
only has to be robust enough to support the current of that same bulb.
1 amp.

yes, we've covered that already.

Can you find an example of a CFL that draws more than 100 watts? What
point are you trying to make, anyway?

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

wrote:

On Mon, 19 Jan 2009 19:57:12 -0600, CJT wrote:


Nate Nagel wrote:


wrote:


On Mon, 19 Jan 2009 19:23:56 -0600, AZ Nomad
wrote:


On Mon, 19 Jan 2009 15:59:38 -0500,
wrote:


Correct you are, but what happens to a fixture that is rated for a 100
watt incandescent bulb when you use it for something other than
lighting? Are you saying that as long as you don't develop 100 watts
of heat then the fixture will be just fine?


Yes, so long as you aren't actually drawing more than 100W.

nate


I think perhaps his point is how the power factor can affect the current
vs watt relationship.


My point is that a light fixture rated for a 100 watt incandescent
only has to be robust enough to support the current of that same bulb.
1 amp.

Then I guess I don't see where the argument is. The other guy said it
would be ok to draw no more than 100W, which is consistent with what
you're saying.

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

In article , CJT wrote: (edited slightly)
Nate Nagel wrote:

wrote:

On 19 Jan 09 19:23:56 -0600, AZ Nomad said:

On 19 Jan 2009 15:59:38 -0500, wrote:

The ceiling fixtures in our house all have labels indicating the
maximum wattage (incandescent) bulb to place in the fixture.
I assume this is a heat-based limit...

of course it is. Do you think the actual light causes the fixture
to catch fire?

Although heat may and probably is the issue, over wattage through
current draw certainly could become a problem.

A bulb that draws 25W to produce the light of a 75W incadescent bulb
isn't going to overtax a fixture designed for 75W.

Correct you are, but what happens to a fixture that is rated for a 100
watt incandescent bulb when you use it for something other than
lighting? Are you saying that as long as you don't develop 100 watts
of heat then the fixture will be just fine?

Yes, so long as you aren't actually drawing more than 100W.

I think perhaps his point is how the power factor can affect the current
vs watt relationship.

My experience so far is that even with lower power factor, CFLs
usually draw less current and VA than incandescents of same light output.
And in the few cases when they draw more, they don't draw much more. And
my experience so far is that no spiral CFLs draw more current and VA than
"equivalent incandescent" despite lower power factor.

And in case anyone wonders about VA and amps being billed or amounting
to fuel consumption - only "real watts" get billed, and current other than
that associated with "real watts" has much less contribution to fuel
consumption for generators than "real watts" do.
The reactive and harmonic amps merely increase wire and transformer and
generator winding heating (that loss causes a minor increase in fuel
consumption, small compared to that needed to deliver same extra amps to
resistive loads), maybe also vibration in the generators. Power companies
bitch about power factor mainly out of need to accomodate amps not
resulting in billable watts, and they often surcharge commercial and
industrial customers (not residential ones) for power factor of a customer
as a whole falling below .8. The issue is wire and transformers carrying
amps not associated with billable watts or watt-hours.

Replacing a 60 watt incandescent with a CFL of wattage 13 to 19 watts
will reduce coal burning even if both draw the same amps.

- Don Klipstein )

On 1/19/2009 5:40 PM Nate Nagel spake thus:

wrote:

On Mon, 19 Jan 2009 19:23:56 -0600, AZ Nomad
wrote:

On Mon, 19 Jan 2009 15:59:38 -0500, wrote:

The ceiling fixtures in our house all have labels indicating the maximum
wattage (incandescent) bulb to place in the fixture.
I assume this is a heat-based limit...

of course it is. Do you think the actual light causes the fixture to catch
fire?

Although heat may and probably is the issue, over wattage through
current draw certainly could become a problem.

A bulb that draws 25W to produce the light of a 75W incadescent bulb
isn't going to overtax a fixture designed for 75W.

Correct you are, but what happens to a fixture that is rated for
a 100 watt incandescent bulb when you use it for something other
than lighting? Are you saying that as long as you don't develop
100 watts of heat then the fixture will be just fine?

Yes, so long as you aren't actually drawing more than 100W.

I wouldn't sweat the "drawing more than 100 watts" part. Really.

Think about it: I'd feel safe betting that *almost all* light fixtures
(sockets) are electrically capable of handling far more than their rated
values in watts. Many standard Edison-base light sockets are rated at
660 watts.

The issue isn't too much current flowing through the contacts and wires:
it's too much heat being generated by the bulb.


--
"I know I will go to hell, because I pardoned Richard Nixon."

- Former President Gerald Ford to his golf partners, as related by
the late Hunter S. Thompson

In article m, David
Nebenzahl wrote:

On 1/19/2009 5:40 PM Nate Nagel spake thus:

SNIP a fair amount to edit for space
Yes, so long as you aren't actually drawing more than 100W.

I wouldn't sweat the "drawing more than 100 watts" part. Really.

Think about it: I'd feel safe betting that *almost all* light fixtures
(sockets) are electrically capable of handling far more than their rated
values in watts. Many standard Edison-base light sockets are rated at
660 watts.

I once saw a "bankers' lamp" style desk lamp rated for 60 watt tubular
"T10" bulbs produce a slight burning odor and have wire insulation
slightly char with a 60 watt bulb. It was plenty fine and dandy with a 40
watt one.

I suspect the fixture was manufactured and tested in a country where the
prevailing line voltage is 230V, or most thermal testing was done with a
230V bulb or otherwise vacuum-containing bulb. I suspect most 60 watt
230V bulbs of that style have a vacuum - most bulbs drawing less than
about 20-25 watts per visibly-apparent inch of filament length have a
vacuum.
But the 120V 60 watt version of that bulb is gas filled. (Gas allows
higher filament temperature, but conducts heat from the filament to the
surface of the bulb). So I am guessing that the 120V version runs hotter
than the 230V version. It did indeed run quite hot.
Meawhile, the USA-usual 40-watt version has a vacuum and runs cool.

The issue isn't too much current flowing through the contacts and wires:
it's too much heat being generated by the bulb.

- Don Klipstein )

On 1/20/2009 3:27 PM Don Klipstein spake thus:

In article m, David
Nebenzahl wrote:

On 1/19/2009 5:40 PM Nate Nagel spake thus:

SNIP a fair amount to edit for space
Yes, so long as you aren't actually drawing more than 100W.

I wouldn't sweat the "drawing more than 100 watts" part. Really.

Think about it: I'd feel safe betting that *almost all* light fixtures
(sockets) are electrically capable of handling far more than their rated
values in watts. Many standard Edison-base light sockets are rated at
660 watts.

I once saw a "bankers' lamp" style desk lamp rated for 60 watt tubular
"T10" bulbs produce a slight burning odor and have wire insulation
slightly char with a 60 watt bulb. It was plenty fine and dandy with a 40
watt one.

Yes.

Just to make the point excruciatingly clear, at the risk of beating this
already-dead horse to death: even though the ratings have little to do
with the amount of current drawn by the bulb, I would never attempt to
exceed those ratings, say by putting a 75-watt bulb in a fixture labeled
for 60 watts. In fact, as pointed out by your example, it would be
better to err on the side of caution, especially if in doubt. If the
fixture says 100 watts, use a 75 watt bulb, maximum.


--
"I know I will go to hell, because I pardoned Richard Nixon."

- Former President Gerald Ford to his golf partners, as related by
the late Hunter S. Thompson

But the electronics in a CFL may fail faster if they get hot due to being in
an enclosed light.

"Don Klipstein" wrote in message
...
In article m, David
Nebenzahl wrote:

On 1/19/2009 5:40 PM Nate Nagel spake thus:

SNIP a fair amount to edit for space
Yes, so long as you aren't actually drawing more than 100W.

I wouldn't sweat the "drawing more than 100 watts" part. Really.

Think about it: I'd feel safe betting that *almost all* light fixtures
(sockets) are electrically capable of handling far more than their rated
values in watts. Many standard Edison-base light sockets are rated at
660 watts.

I once saw a "bankers' lamp" style desk lamp rated for 60 watt tubular
"T10" bulbs produce a slight burning odor and have wire insulation
slightly char with a 60 watt bulb. It was plenty fine and dandy with a 40
watt one.

I suspect the fixture was manufactured and tested in a country where the
prevailing line voltage is 230V, or most thermal testing was done with a
230V bulb or otherwise vacuum-containing bulb. I suspect most 60 watt
230V bulbs of that style have a vacuum - most bulbs drawing less than
about 20-25 watts per visibly-apparent inch of filament length have a
vacuum.
But the 120V 60 watt version of that bulb is gas filled. (Gas allows
higher filament temperature, but conducts heat from the filament to the
surface of the bulb). So I am guessing that the 120V version runs hotter
than the 230V version. It did indeed run quite hot.
Meawhile, the USA-usual 40-watt version has a vacuum and runs cool.

The issue isn't too much current flowing through the contacts and wires:
it's too much heat being generated by the bulb.

- Don Klipstein )

On Mon, 19 Jan 2009 20:37:16 -0500, wrote:
On Mon, 19 Jan 2009 19:23:56 -0600, AZ Nomad
wrote:

On Mon, 19 Jan 2009 15:59:38 -0500, wrote:

The ceiling fixtures in our house all have labels indicating the maximum
wattage (incandescent) bulb to place in the fixture.

I assume this is a heat-based limit...
of course it is. Do you think the actual light causes the fixture to catch
fire?

Although heat may and probably is the issue, over wattage through
current draw certainly could become a problem.

A bulb that draws 25W to produce the light of a 75W incadescent bulb
isn't going to overtax a fixture designed for 75W.

Correct you are, but what happens to a fixture that is rated for
a 100 watt incandescent bulb when you use it for something other
than lighting? Are you saying that as long as you don't develop
100 watts of heat then the fixture will be just fine?

As long as you don't exceed the current and heat ratings, you'll
be fine.

Correct you are, but what happens to a fixture that is rated for
a 100 watt incandescent bulb when you use it for something other
than lighting? Are you saying that as long as you don't develop
100 watts of heat then the fixture will be just fine?

As long as you don't exceed the current and heat ratings, you'll
be fine.

So now you are bringing current into the equation. I'm glad the light
bulb turned on.

On Mon, 19 Jan 2009 21:17:09 -0500, wrote:

Correct you are, but what happens to a fixture that is rated for
a 100 watt incandescent bulb when you use it for something other
than lighting? Are you saying that as long as you don't develop
100 watts of heat then the fixture will be just fine?

As long as you don't exceed the current and heat ratings, you'll
be fine.

So now you are bringing current into the equation. I'm glad the light
bulb turned on.

I never proposed exceeding a fixture's current rating.

On Mon, 19 Jan 2009 20:34:13 -0600, AZ Nomad
wrote:

On Mon, 19 Jan 2009 21:17:09 -0500, wrote:

Correct you are, but what happens to a fixture that is rated for
a 100 watt incandescent bulb when you use it for something other
than lighting? Are you saying that as long as you don't develop
100 watts of heat then the fixture will be just fine?

As long as you don't exceed the current and heat ratings, you'll
be fine.

So now you are bringing current into the equation. I'm glad the light
bulb turned on.

I never proposed exceeding a fixture's current rating.

But you and others originally omitted any mention of current,
and focused only on heat instead.