T 5 lamps

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Heat loss is the real hidden cause. Heat loss is where almost all forms of energy transformation lose the "money" when you change electromotive force to "light energy" the heat is not used. When you step down or up in voltage the heat is not used. Heat is a byproduct caused by electrons hitting each other and kinetic energy is converted to heat. $$$$ The difference should be alot more light out of the lamps a 26 watt fluorescent lamp will give you a lot more light then a 100 watt incandescent lamp. T-5 to T-12 I don't know how the light output will change.
 
Jim W in Tampa said:
Bit confused on wattage of t5.They say 28 watts for the 4 footers.Have 40 of them installed 40 x 28 = 1120 watts but they are using almost 20 amps at 120 wich is 2400 watts.Am i missing something ?Ballast amps are 1 for 2 lamp fixture.
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If the power factor is not 1 then the 2400 watts is not real power but apparent power, part of which is the reactive power component for which you will not be getting charged for. The difference probably comes partly from a low power factor and the ballast inefficiency. Are you using magnetic or elecronic ballasts? Electronic ballasts tend to be a lot better at efficiency and at power factor. e/m
 
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What really will help here alot with the T-5's most are electronic ballasted type and majorty of them have pretty high ballast factor on hand most useally run something like .95 BF IIRC some have much higher like 1.15 BF that will kick more light but will increase wattage a little sorta like overdrive on your truck.

i know Advance is common ballast they used in the T-5's but there are other manufacters as well and most are pretty close to eachother sizewise and ratings as well.

Merci, Marc
 
Energy-Miser said:
If the power factor is not 1 then the 2400 watts is not real power but reactive power and you are not getting charnged for all of it. The difference, probably comes partly from a low power factor and the ballast inefficiency. Are you using magnetic or elecronic ballasts? Electronic ballasts tend to be a lot better at efficiency and at power factor. e/m
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They are electronic
 
Jim W in Tampa said:
20 fixtures x 2 lamps

All of this is making me rethink them screw in type we use to replace incandesant bulbs,might be just as big a rip off.
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Good point. I've casually wondered this myself. Someone ought to test this with an ammeter. They don't seem to get hot, though, I can definitely say that.
 
Jim W in Tampa said:
If it turns out to really being 2400 watts then that 28 watts per bulb is false advertising.
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Jim, it's not 'false advertising' that number is the wattage of the lamp when supplied by the correct ballast.

Your circuit does not 'supply' the lamps, your circuit supplies the ballast.
 
Jim W in Tampa said:
All of this is making me rethink them screw in type we use to replace incandescent bulbs,might be just as big a rip off.
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WOW.....all this time no one has realized what you just figured out....:grin:

Jim, they are not a 'rip off' they produce more lumens per watt then incandescents.
 
iwire said:
WOW.....all this time no one has realized what you just figured out....:grin:

Jim, they are not a 'rip off' they produce more lumens per watt then incandescents.
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OK lets say i put in a 100 watt to get the light of what a 60 would gave me.How many watts will this cost me ?Its misleading
 
I am surprised at some of the answers here.

Bottom line is the circuit load must be calculated by the markings on the ballast regardless of the lamp wattage the NEC requires this as the lamp wattage is meaningless at the supply voltage.


Check out 220.18(B) it directly applies here.
 
Jim W in Tampa said:
OK lets say i put in a 100 watt to get the light of what a 60 would gave me.How many watts will this cost me ?Its misleading
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It will draw what it says it draws.

There is no 'separate' ballast on a screw in CFL, the rating is the rating of the entire unit.

Not the same as the fixtures you are talking about.
 
only thing I can think of to add is that you may need a true RMS meter to get an accurate reading, but I don't think it will make THAT big a difference
 
iwire said:
It will draw what it says it draws.

There is no 'separate' ballast on a screw in CFL, the rating is the rating of the entire unit.

Not the same as the fixtures you are talking about.
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OK then they are a winner.I have found that it takes a 100 to really equal a 60 but thats still better deal.
 
RayS said:
only thing I can think of to add is that you may need a true RMS meter to get an accurate reading, but I don't think it will make THAT big a difference
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I was thinking that, specially because i have read somewhere that the electronic ballasts introduce non-linearities. This means that although your measurement of the voltage would be accurate (as it is still a sinusoidal of 60 hz frequency), the measurement of the current may be off, because the current will have harmonics in it which is the result of the operation of the non-linear ballast. Now, is there enough inaccuracy in reading the RMS amperage due to this to make up the difference we are talking about here iis probably open to debate. It may be a contributing factor. e/m.
 
Energy-Miser said:
I was thinking that, specially because i have read somewhere that the electronic ballasts introduce non-linearities. This means that although your measurement of the voltage would be accurate (as it is still a sinusoidal of 60 hz frequency), the measurement of the current may be off, because the current will have harmonics in it which is the result of the operation of the non-linear ballast. Now, is there enough inaccuracy in reading the RMS amperage due to this to make up the difference we are talking about here iis probably open to debate. It may be a contributing factor. e/m.
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How would harmonics affect a 120 volt circuit?

but they are using almost 20 amps at 120 which is 2400 watts
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iwire said:
Harmonic currents do exist on single phase circuits but they do not 'add up' on the neutral like they do with three phase.
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I guess that should have asked if this were a two wire circuit (which I assumed that it is given his measurement is on a 120 volt circuit). A two wire circuit would have current equal in each conductor.
 
On a two wire circuit with harmonic currents a standard amprobe will not read accurately. A true RMS amp clamp is needed to accurately measure the current on a two wire circuit with harmonic currents.

I believe that was what EM was trying to point out.
 
Just curious, are you sure that the lamps are 28w? I just installed 101 two lamp fixtures that used 54 watt lamps. The ballast 1 amp draw with two 54w lamps. I do not remember if the ballast listed different wattage lamps.

Jim
 
Jim, the 54s are high output versions while the 28s are the standard T-5 wattage for that length. The pins are the same so IMO it is a real pain.

I service a facility that uses 100s of the 28 and 54 watt versions and the maintenance guys can never seem to install the right lamp size into the fixtures.
 
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