Thiết bị & Hệ thốngCâu 343 / 521
How must overcurrent devices in an emergency system be coordinated?
a.Coordination is prohibited
b.Selectively coordinated with all supply-side overcurrent protective devices
c.Coordination is required only above 1000 volts
d.Coordination is not addressed by the NEC
Giải thích
Section 700.32 requires emergency-system overcurrent protective devices to be selectively coordinated with all supply-side overcurrent devices. Selective coordination ensures that only the device nearest a fault opens, so a fault on one branch does not shut down the entire emergency system.
Trích dẫn luật: 2023 NEC §700.32Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
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