An toànCâu 431 / 521
An energized electrical work permit is generally required when:
a.Any electrical work is performed, even de-energized
b.Energized work is justified because de-energizing would introduce additional hazards or is infeasible, and the work is within the restricted approach or arc flash boundary
c.The job simply takes longer than eight hours
d.Working on a 24-volt control circuit
Giải thích
An energized work permit is required when justified energized work occurs within the restricted approach or arc flash boundary. Routine de-energized work does not need one, job duration is irrelevant, and very low-voltage circuits below the shock/arc thresholds generally do not require the permit.
Trích dẫn luật: NFPA 70ELuyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- An arc-flash study shows an available incident energy of 8 cal/cm² at the working distance. The arc-rated clothing and PPE must have an arc rating of:
- Rubber insulating gloves used for energized work on a 480V system must be:
- Under Cal/OSHA and NFPA 70E, the primary/preferred way to protect workers from electrical hazards is to:
- Before you rely on a voltage detector to verify absence of voltage, you should:
- You are servicing a circuit that feeds a variable frequency drive (VFD) with large DC-bus capacitors. After disconnecting power you must:
- You are installing a 480Y/277V panelboard with exposed live parts likely to require examination while energized. There is a concrete (grounded) wall on the opposite side of the working space (Condition 1). What is the minimum working-space depth in front of the panel?
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