Thiết bị & Hệ thốngCâu 326 / 521
A storage-battery emergency source must be capable of maintaining the total emergency load for what minimum time and voltage?
a.30 minutes at 80% of nominal
b.1 hour at 90% of nominal
c.2 hours at 100% of nominal
d.1 1/2 hours at not less than 87 1/2% of nominal voltage
Giải thích
Section 700.12 requires a storage battery serving as an emergency source to maintain the total load for a minimum of 1 1/2 hours without the voltage falling below 87 1/2 percent of nominal. Shorter durations or lower voltage thresholds do not meet the emergency-source requirement.
Trích dẫn luật: 2023 NEC §700.12Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
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