Calculating power use.

[Reg1952]

When I am figuring out how much power my florescent lights will use do I add the bulb wattage and the ballast wattage together to get total usage. Or does the ballast just use power when starting? eg. 2 32 watt bulbs and a ballast that draws 1 amp(120 watts) = 184 watts per fixture? Am I doing this right??

 

[Rookie2]

Just add the lamp wattage together to be close. the actual is printed on the ballast.

 

[zkling]

How accurate of a number do you want? Do you have a clamp amp meter?

 

[sberry]

I am with zkling,,, what are you trying to do? This is just an easy deal. When I size most circuits I figure 100 watts to the amp. I realize that is not correct but its super easy no miss way to leave the headroom without havin to do a bunch of figurin.

 

[Reg1952]

Just trying to get a rough idea what type of wattage 12 T8 fixtures with 2 bulbs per fixture would pull.

 

[ddawg16]

Assuming 32w bulbs....24 bulbs x 32w = 6.4A....

Assuming you don't want to exceed 80% for a continuous load...even with a 15a ckt for lighting, your fine.

 

[Mustang51js]

Like said above, 24x32=786/120(volts)= 6.4 amps

 

[gasaxeman]

Calculate from what is listed on the ballast

 

[Reg1952]

So if I times .786 x 8 (8 hours a day) = 6.288 kw x 12.9 cents a kw = 81.11 cents a day to run my lights?