Branch Circuits & FeedersQuestion 23 of 120
The rule permitting the next higher standard overcurrent device rating above the conductor ampacity may be applied only where that device rating does not exceed what value?
a.400 amperes
b.600 amperes
c.1,000 amperes
d.800 amperes
Explanation
The round-up allowance stops at 800 amperes; above that rating the overcurrent device must not exceed the ampacity of the conductors it protects. The other values are not thresholds in 240.4(B), and choosing 600 A would needlessly restrict legitimate designs in the 601 to 800 A range.
Law Reference: 2023 NEC §240.4(B)Practice all 120 questions free — no signup required.
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