I am circuiting 100 watt Metal Halide fixtures, 277 v, stanchion mounted on exterior platforms and walkways. What should I use for circuit loading:
a) 100w= 130 input wattage (from ballast chart) or
b) 1.15 max. input amps (from same chart).
I, along with the people I have worked with, always used the input wattage, but have recently been told to use the input amps.
130 input wattage vs 1.15 amps (318 watts) which is about 2.5 times more. Thats a lot more breakers.