Branch Circuits & FeedersQuestion 20 of 120
A 277-volt feeder supplies three continuous lighting loads of 12, 15 and 18 amperes. What is the minimum standard feeder overcurrent device rating?
a.50 amperes
b.45 amperes
c.60 amperes
d.70 amperes
Explanation
Total the loads first: 12 + 15 + 18 = 45 A, all continuous, so the device must be at least 45 x 1.25 = 56.25 A and the next standard rating is 60 A. The 45 A answer omits the continuous-load factor, 50 A is below the calculated minimum, and 70 A overshoots the next standard size.
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