Light Bulb Question...100 watts vs. 60 watts

[Ken_McE]

Torchboy:
A CFL that uses 60 W will be the equivalent of a 300 W incandescent. You probably don't want six of those.

Based on his first post, JME wants around 10,000 lumens.


mmpteach
What do you do if you think your electrical wires may be dry?

move? *


Matrixshaman:
I don't understand this question nor some of the responses. You don't want your electrical wiring to be wet! What are you talking about?

My bad. It is not that you have moisture in the wires. My concern is that if JSM heats the wires in the fixture hot enough, long enough, he may bake out the plasticizer in the insulation. You combine this with a little vibration, maybe the wire is a bit pinched or stretched somewhere, you start getting possibilities...

ab1ht:
Why not switch to LED replacements? They sell these in most hardware stores now. A little pricey, yes, but they will last forever.

Many of the over the counter LED products are not quite ready for prime time.


* Not really

 

[TorchBoy]

Torchboy:
A CFL that uses 60 W will be the equivalent of a 300 W incandescent. You probably don't want six of those.

Based on his first post, JME wants around 10,000 lumens.

Sorry, I didn't remember that 100 W bulbs at 110 V are supposedly more efficient than 100 W bulbs at 230 V, but I figure 6 x 60 W CFLs could give you 21,000 - 24,000 lumens.

 

[Ken_McE]

I figure 6 x 60 W CFLs could give you 21,000 - 24,000 lumens.

I think that we are using different rules of thumb (well, I'm using rules of thumb) in our calculations. I assume that a CFL will be three times as efficient as an incan. I think you are assuming four times as efficient? That led me to compare a 60 watt CFL with a 180 watt incan, I figure that's around 3,000 lumens per bulb, 6 X 3,000 = ~ 18,000 lumens, that's almost double what he needs, so maybe that would be a little bright.

I use a somewhat lower figure because I have repeatedly run into misleadingly labeled CFLs, and I have come to distrust the manufacturers. What I'd like to do is test some and see for myself what's what, but realistically I know I'm never going to rent time on a integrating sphere, so I settle for just using conservative estimates.

 

[TorchBoy]

I think that we are using different rules of thumb (well, I'm using rules of thumb) in our calculations. I assume that a CFL will be three times as efficient as an incan. I think you are assuming four times as efficient? That led me to compare a 60 watt CFL with a 180 watt incan, I figure that's around 3,000 lumens per bulb, 6 X 3,000 = ~ 18,000 lumens, that's almost double what he needs, so maybe that would be a little bright.

Yes we do have different rules of thumb but (once I realised it) I was trying to get around that by using lumens. According to the table at the link I posted, a 100 W tungsten incandescent at 220 V provides 13.8 lm/W, while a 100 W tungsten incandescent at 120 V provides 17.5 lm/W(!) so CFLs here in New Zealand are a bigger step up from incandescent than in the USA. FWIW a rule of thumb of 5x is used on CFL packaging here.

CFLs are said in the table to be 46–72 lm/W, and I've seen 63-70 lm/W claimed on the top branded ones here. A total 18,000 lumens would be quite possible, although possibly a bit low for big CFLs at just 50 lm/W.

I still reckon he probably wouldn't want six 60 W CFLs.

 

[LEDninja]

Where can you buy 60watt CFL? What do you do if you think your electrical wires may be dry?

Why do you think your electrical wires may be dry?
Household electrical circuits are 15A. Electricians simply use wire rated for that. 4*100W light bulbs use 4A or 1/4 of normal wire used in household wiring. Going from 4*60W to 4*100W should not be a problem for the wiring.

Now if your house is wired by an electrical engineer who calculates the exact gauge of wire needed for an application and use that then all bets are off.

 

[mpteach]

Im no electrician but as i understand it.

Household electrical cuircuits are 20A and 15A. Code even requires 20A cuircuits for some things like bathrooms. For receptacles and lighting 14 guage is for 15A cuircuits and 12 guage is for 20A. For long runs beyond a certain distance you go to bigger guage. Circuits to dedicated equipment can be different.

That electrical engineer would read the codebook chart and use the required stardard size wires, or for dedicated equipment he would use the specs. No much calculating involved.

 

[LEDninja]

That electrical engineer would read the codebook chart and use the required stardard size wires, or for dedicated equipment he would use the specs. No much calculating involved.

Ha Ha Ha
My experience is exactly the opposite. Engineers tend to do what they are taught in school. Some do not know the codebook exist. For dedicated equipment he would WRITE the specs.

When I 1st started to work (I was still doing piping drafting) I went down to the shop during breaks. One day I saw an assembler rewiring a piece of equipment built by the R&D department. I asked why - he knew nothing about the stuff. He said "look". I saw a sea of green. "Well its still 6 months to Christmas but what is wrong?" I got a lecture on wiring colours: black hot, white neutral, green ground. Some people would touch a terminal block attached to a green wire to ground themselves (same as a computer guy touching a power supply case) and having green wire running power is a NO-NO. The Ontario Hydro Safety inspector had passed through and had a fit.

I got lots more stories of the wild and wacky ways some engineers do things.

 

[mpteach]

How on earth did they think that equipment could ever be certified? How could they even test or troublshoot their own crap if it was all green? If there was high voltages thats unsafe. I cant think of an EE not knowing green is ground. That wouldnt fly in his ee school projects. I would have fired that really bad proffesional engineer if i was his boss.

I can imagine a non-EE engineer who took one basic electricity course his sophmore year, using ohms law to calculate the incorect wire sized needed to add a light socket to his house or something of that nature, that wouldnt surpise me.

 

[Alaric Darconville]

I have put six 100 watt light bulbs in my room. Each ceiling socket is rated for 60 watts, not 100. How much of a fire hazard is this? Also how long would it tale of being on?

If they are all controlled from the same switch, that could cause problems in itself. The surge current when all six lamps are energized at once can exceed the capacity of the switch to handle (some switches are rated for 600W max incandescent load, however*) and the surge may also cause an older breaker to trip.

This is because the filaments pass more current when cold/warming up than when they are at their operating temperature.

Also, if one of the bulb blows, it can cause arcing to occur inside the bulb. Add that arc and resultant current draw to the remaining 500W, and that could trip the breaker before the bulb's own fuse blows (yes, many incandescent bulbs have an internal fuse). Also, considering that many bulbs blow when you first apply power, you can see how you can have the massive cold-filament surge current combined with the arc.

So now your problem is that you're exceeding the fixtures' individual specifications and you may be exceeding that branch circuits specifications.

And if it does catch on fire, your insurance company may choose to deny your claim based on exceeding the fixtures' specifications alone.


*The max incandescent load takes into account the cold filament surge current

 

[mpteach]

If they are all controlled from the same switch, that could cause problems in itself. The surge current when all six lamps are energized at once can exceed the capacity of the switch to handle (some switches are rated for 600W max incandescent load, however*) and the surge may also cause an older breaker to trip.

This is because the filaments pass more current when cold/warming up than when they are at their operating temperature.

Also, if one of the bulb blows, it can cause arcing to occur inside the bulb. Add that arc and resultant current draw to the remaining 500W, and that could trip the breaker before the bulb's own fuse blows (yes, many incandescent bulbs have an internal fuse). Also, considering that many bulbs blow when you first apply power, you can see how you can have the massive cold-filament surge current combined with the arc.

So now your problem is that you're exceeding the fixtures' individual specifications and you may be exceeding that branch circuits specifications.

And if it does catch on fire, your insurance company may choose to deny your claim based on exceeding the fixtures' specifications alone.


*The max incandescent load takes into account the cold filament surge current

The breaker blows anytime the branch specs are exceeded. Thats more an anoyance than safety issue. Exceeding the rating of the fixtures is a safety issue and the insurance companies could deny a claim because of that. Ive cleaned up firedamaged houses, nasty nasty.

Make sure you have fresh batts in your smoke detector lol.