Hi how many four tube fluorescent fittiings can you have on one 10 amp circuit in a commercial installation I know ten is the norm but have to be sure

You need the voltage supplied to the lights and the watts of each tube. Add your watts together then divide that by the voltage that will give you your amps. Lighting in the NEC is consider a contious load so your over current device can only be rated at 80%.

Calculating the load of a fluorescent fixture is a bit more than just adding the wattage of the lamps.

There is still the ballast factor.

Each ballast has a nameplate that states the total amp draw, combining the wattage of the lamps and VA of the ballast.

Calculating the load of a fluorescent fixture is a bit more than just adding the wattage of the lamps.

There is still the ballast factor.

Each ballast has a nameplate that states the total amp draw, combining the wattage of the lamps and VA of the ballast.

Good to know. I learned something new