t8 fixture power usage?

[slakwhere]

so the new garage i'm buying only has 2 60 watt bulbs in the whole thing

i need to add some lighting, and it looks like T8 is the way to go... but i'm curious what a standard 32w bulb pulls for amps. is the standard equation of Watts/volts = Amps? or do these things peak/burst/pulse higher?

my plan is to go 36 bulbs (4 per fixture, 9 fixtures) on 2 separate switches, but i'm wondering what kind of load this will generate so i can calculate the wire gauge accurately. current plan is 16 gauge wire so each circuit can handle 20 amps.

5 fixtures X 4 bulbs X 32 watts = 640 watts / 120v = 5.3 amps?
9 fixtures X 4 bulbs X 32 watts = 1152 watts / 120v = 9.6 amps?

 

[Aceman]

If I remember right, one 4-lamp 4' T8 ballast draws right at one amp.

 

[slakwhere]

that seems to stand in line with my calculations, thanks aceman!

 

[mrb]

that would be 12ga wire, not 16.

on fluorescent fixtures ignore the bulb wattage -you have to look at the current draw printed on the ballast.

 

[slakwhere]

that would be 12ga wire, not 16.

on fluorescent fixtures ignore the bulb wattage -you have to look at the current draw printed on the ballast.

mrb guess i have to go back to home depot and see what the ballasts say they draw

 

[StaggeringGoat]

You also have to calculate the ballast factor, some are less than 1, some are more than 1. That means they feed the bulbs more or less wattage. I have some 2-tube fixtures with Sylvania ballasts and they only draw 50 watts, even though there is 64 watts of tubes.

 

[slakwhere]

with 12ga wire and 5 lights per circuit i should be WAY under what's expected... but i'll double check ballast #'s to be sure.