CFLs vs incandescent "max wattage" cautions in overhead fixtures....

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snipped-for-privacy@mucks.net wrote:

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

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?
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snipped-for-privacy@mucks.net wrote:

Good God.
There are two reasons why fixtures have a maximum current rating (well, really, they're the same reason, but let's ignore that for now.) One is the actual current passing through the wires and socket. There is no Edison-base CFL commonly available that draws more than 23W, so you're good there. The other reason is heat. Unless someone can demonstrate that a 23W (or whatever) CFL can actually put out *more* heat than a 60W light bulb, then that is also not a concern.
Now some posters have mentioned shortened life in certain orientations/enclosed fixtures - that is something of a concern, but won't damage the fixture itself or the house's wiring unless either current or heat ratings of the fixture are exceeded.
Go ahead, argue with the above. I'm sure you'll find *SOMETHING* in there...
nate
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wrote:

I will find a flaw in your reasoning. When you say "Unless someone can demonstrate that a 23W (or whatever) CFL can actually put out *more* heat than a 60W light bulb, then that is also not a concern." you are saying that that fixture would never be used for high current devices. Therefore you have no concern.
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snipped-for-privacy@mucks.net wrote:

What the HELL are you talking about?
The OP asked if it was OK to put a "100W equivalent" CFL in a 60W rated fixture. A "100W" CFL typically draws about 23 watts. What the heck does that have to do with "high current devices?"
nate
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26 watt ones ("more truly 100 watt incandescent equivalent") are now so common as to be available at CVS drugstores. 30 and 42 watt ones are somewhat common in "big box" major chain home centers, though 30-watt *might* be a bit specific to Lowes. 30 watt has "incandescent equivalence" being what I would call "mildly outshining a 100 watt 'standard' incandescent when it is young and in favorable conditions". 42 watt I would call "a bit dimmer than 'standard' 150 watt incandescent". (I somewhat remember a "standard" 150 watt 120V 750-hour-rated incandescent of "Big-3 brand" and with CC-8 style filament having rated light output somewhere in the 2900's of lumens.)
I have seen one size bigger still in some True Value hardware stores. I forget the wattage - I suspect somewhere in the 50's. Light output in lumens I somewhat remember as "close to 200 watt incandescent equivalence". (Keep in mind that a 120V 200W incandescent of "Big 3" brand and with "CC-8" style filament and rated to have average life expectancy of 750 hours produces close to 4,000 lumens.)
- Don Klipstein ( snipped-for-privacy@misty.com)
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On Mon, 19 Jan 2009 20:47:48 -0600, AZ Nomad

No I am interested in making a point. I have done that.
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snipped-for-privacy@mucks.net wrote:

Judging by the post to which you are responding, it seems the point you've made is that you belong in a killfile.
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Nate Nagel wrote:

I think perhaps his point is how the power factor can affect the current vs watt relationship.
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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.
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snipped-for-privacy@mucks.net wrote:

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?
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On 1/19/2009 6:21 PM Nate Nagel spake thus:
>

Even if they existed, it wouldn't matter: the electrical parts of any lamp socket are perfectly capable of handling far more than 100 watts (1 amp at 120 volts, nominal). A typical socket rating is 660 watts (at least for ceramic sockets, maybe somewhat less for phenolic resin).
The problem is not excessive current (or power, if you prefer): it's heat.
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Nebenzahl wrote:

I seem to think that many are rated only 250-300 watts.

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On 1/20/2009 3:29 PM Don Klipstein spake thus:

>

That sounds right; still 2.5x-3x the rating for a 100 watt light, plenty of "headroom".
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snipped-for-privacy@mucks.net wrote:

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

>>>>>

>>>>

>>>

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.
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Nebenzahl wrote:

<SNIP a fair amount to edit for space>

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.

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

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.
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