Fill in the blank with the appropriate answer.

When calculating inductive and LED lighting loads for circuits supplying lighting units that have ballasts, transformers, autotransformers, or LED drivers, the calculated load shall be based on ____________.

A. the total wattage of the lamps of the lighting units

B. the total amperage of the lighting units

C. the combined total of the wattage and the amperage of the lighting units

D. There is no need to calculate, as all branch circuits are rated at 20A

 

Answer: B

Article 220 of the 2011 NEC focuses on the load calculations for branch circuits, feeders and services. As noted in 220.18(B), "For circuits supplying lighting units that have ballasts, transformers, autotransformers, or LED drivers, the calculated load shall be based on the total ampere ratings of such units and not on the total watts of the lamps."

Owen is the owner and president of National Code Seminars and the holder of master electrician certifications in 46 states. He can be reached at necexpert@aol.com.