Services, Grounding & BondingQuestion 56 of 120
How must a panelboard be protected against overcurrent?
a.By an overcurrent device rated at 125 percent of the panelboard rating
b.By the sum of the branch-circuit devices installed in it
c.By an overcurrent device having a rating not greater than the panelboard rating
d.No separate protection is required if the feeder conductors are properly sized
Explanation
Each panelboard must be protected by an overcurrent device rated no higher than the panelboard rating, located either in the panelboard itself as a main or ahead of it in the feeder. Summing the branch devices routinely exceeds the panelboard rating because of diversity, and no code rule allows protecting a panelboard at 125 percent of its rating.
Law Reference: 2023 NEC §408.36Practice all 120 questions free — no signup required.
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