Fixture wattage or ballast rating?

[rrc14]

When sizing fluorescent/HID lighting circuits do we use the fixture wattage or the ballast rating? Is there some multiplier that is used with the fixture wattage to estimate the ballast power requirements?

There was an excellent thread on this forum not too long ago on this topic, but I can't seem to locate it.

Thanks,

 

[Dennis Alwon]

When sizing fluorescent/HID lighting circuits do we use the fixture wattage or the ballast rating? Is there some multiplier that is used with the fixture wattage to estimate the ballast power requirements?

There was an excellent thread on this forum not too long ago on this topic, but I can't seem to locate it.

Thanks,

You would use the ballast rating not the wattage of the bulb

 

[Rockyd]

See 220.18(B)