Motors & EquipmentCâu 97 / 120
A hermetic refrigerant motor-compressor has a rated-load current of 20 amperes. What is the maximum branch-circuit short-circuit and ground-fault protective device at the standard 175 percent figure?
a.60 amperes
b.25 amperes
c.45 amperes
d.35 amperes
Giải thích
Protection for a motor-compressor is sized at not more than 175 percent of the rated-load current: 20 x 1.75 = 35 A, which is a standard rating. Where that device still will not carry the starting current it may be increased, but never above 225 percent, which here would be 45 amperes. A 25-ampere device is below the calculated value and would nuisance trip on start.
Trích dẫn luật: 2023 NEC §440.22(A)Luyện miễn phí toàn bộ 120 câu hỏi — không cần đăng ký.
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