Services & DistributionQuestion 106 of 521
A panelboard must have a rating (busbar ampacity) not less than:
a.The minimum feeder capacity required for the load served, as computed per Article 220
b.50% of the service rating
c.The largest single branch circuit only
d.Twice the neutral load
Explanation
Per 408.30, a panelboard must have a rating not less than the minimum feeder or service capacity required for the load computed under Article 220. Sizing only to a single branch circuit or an arbitrary fraction of the service would leave the busbar under-rated for the actual load.
Law Reference: 2023 NEC §408.30Practice all 521 questions free — no signup required.
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