A commercial building has a lighting load of 20,000 watts. The lighting fixtures are 120/277V. What is the minimum branch-circuit ampacity required?

Exam tip

When calculating branch-circuit ampacity for lighting, always multiply the total load by 1.25, as per NEC Article 210.6(A)(1).

Why B is correct

According to 2026 NEC Article 210.6(A)(1), the branch-circuit ampacity is determined by multiplying the total load in watts by 1.25. In this case, 20,000 watts x 1.25 = 25,000 watts. The 25,000 watts divided by 277V gives 90.3A, which rounds up to 100A. The other options are incorrect as they do not meet the calculated requirement.