Dịch vụ & Phân phốiCâu 72 / 521
The interrupting rating of an overcurrent device must be:
a.Equal to the load current
b.At least 65,000 A in all cases
c.Equal to the conductor ampacity
d.Not less than the available fault current at its line terminals
Giải thích
Per 110.9, equipment intended to interrupt current at fault levels must have an interrupting rating at least equal to the available fault current at its line terminals. A device with too low an interrupting rating can fail catastrophically. Load current and conductor ampacity are unrelated to interrupting rating.
Trích dẫn luật: 2023 NEC §110.9Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- The main bonding jumper in service equipment serves to:
- A feeder is protected by a 100 A overcurrent device. Using Table 250.122, the minimum size copper equipment grounding conductor is:
- At other than dwelling units, service equipment must be legibly field-marked with:
- The short-circuit current rating (SCCR) of equipment such as a panelboard means the equipment can:
- In general, conductors may be connected in parallel (electrically joined at both ends) only where the individual conductors are:
- When conductors are installed in parallel, the paralleled conductors of each phase, neutral, or grounded circuit conductor must:
Cập nhật gần nhất: · quy trình kiểm tra
Đội Ngũ Biên Tập PrepPass · Đối chiếu với California CSLB C-10 Electrical Trade Examination · Quy trình kiểm tra