Why does my 42w cfl read 0.57 amps on it? Shouldnt...

renyman

Active Member
it be 0.35 amps if im using 120v? According to this site 42w=0.35.

http://www.jobsite-generators.com/power_calculators.html

This is a big deal for me considering im trying to squeeze every last watt out of my 15a circuit. Ive read from several places that 15a = 1800w and to be safe you shouldnt go over about 1350w ecspecially if youre running a ballast. Should i just go by the watt rating on my cfls or should i assume my bulbs are actually 68w which equals 0.57amps.
 

94blowncobra

Active Member
it be 0.35 amps if im using 120v? According to this site 42w=0.35.

http://www.jobsite-generators.com/power_calculators.html

This is a big deal for me considering im trying to squeeze every last watt out of my 15a circuit. Ive read from several places that 15a = 1800w and to be safe you shouldnt go over about 1350w ecspecially if youre running a ballast. Should i just go by the watt rating on my cfls or should i assume my bulbs are actually 68w which equals 0.57amps.
Sounds like there rating them for min voltage of 100v. But thats right .35a is what you will end up with with 120 v on the nose give or take.
 

Pipe Dream

Well-Known Member
I think electrical devices take more energy to start than to run. Probably just like a buffer zone or something.
 

That 5hit

Well-Known Member
and cfls are self ballast so maybe the deff. is the ballast on the cfl
maybe the ballast has an amp of 0.22 and the bulb has an amp of 0.35 and the both add up to 0.57
 

logzz

Active Member
The 80% rule or the reason people suggest 1350 watt instead of 1500 on 15 amp circuit's only apply, if your running the appliance 3 or more hours.
 

smppro

Well-Known Member
and cfls are self ballast so maybe the deff. is the ballast on the cfl
maybe the ballast has an amp of 0.22 and the bulb has an amp of 0.35 and the both add up to 0.57
Yeah thats what i was thinking, most people forget they have a ballast because they are built in.
 
Don't take the manufacturers specs. Take a measurement yourself. You will find the amp draw is far less than the rated wattage. I measure a 250 watt cfl and found it actually only draws 0.9 amps @ 115 volts that means these are actually 103.5 watts! same goes for a 125 watter it only drew 0.44 amps @ 115 v. These were actual wattage bulbs. I would't be surprised if your 42 watters are drawing less than 0.2 amps! bottom line is to get yourself an clamp on inductive amp meter and check teh current draw yourself
 

renyman

Active Member
Don't take the manufacturers specs. Take a measurement yourself. You will find the amp draw is far less than the rated wattage. I measure a 250 watt cfl and found it actually only draws 0.9 amps @ 115 volts that means these are actually 103.5 watts! same goes for a 125 watter it only drew 0.44 amps @ 115 v. These were actual wattage bulbs. I would't be surprised if your 42 watters are drawing less than 0.2 amps! bottom line is to get yourself an clamp on inductive amp meter and check teh current draw yourself

fuck yeah man. awesome idea. thanks for the replys everyone.
 
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