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

[tnom]

No I am interested in making a point. I have done that.

[tnom]

Nor have you ever thought of a fixture being used to power high current devices.

[Nate Nagel]

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

[tnom]

It depends on the student.

[Nate Nagel]

We were talking about CFLs, not high current devices. (facepalm)

nate

[tnom]

Included in the discussion was the rating of a fixture, or did you forget?

[tnom]

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.

[Nate Nagel]

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

[Don Klipstein]

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 ( [e-mail])

[Don Klipstein]

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 ( [e-mail])

[HeyBub]

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.

[Don Klipstein]

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 ( [e-mail])

[Don Klipstein]

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 ( [e-mail])

[CJT]

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.

[CJT]

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

[Don Klipstein]

In article , Nate Nagel wrote in part:

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 ( [e-mail])

[David Nebenzahl]

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.

[David Nebenzahl]

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.

[David Nebenzahl]

On 1/19/2009 6:55 PM [e-mail] spake thus:

I see you haven't found the right room yet, It's two doors down on the left.

[ropeyarn]

Even at 1.5: I can rest easy :-)

Thanks