An toànCâu 426 / 521
In NFPA 70E, the 'limited approach boundary' is best described as:
a.The distance within which a full arc-flash suit is always mandatory
b.A distance from an exposed energized part within which a shock hazard exists; an unqualified person must not cross it without a qualified escort and appropriate PPE
c.Exactly the same distance as the arc flash boundary
d.A boundary that applies only to DC systems
Giải thích
The limited approach boundary is a shock-protection boundary; crossing it means a shock hazard is present, so unqualified persons need a qualified escort and PPE. It is distinct from the arc flash (thermal) boundary and applies to both AC and DC. The full arc suit is tied to incident energy, not this line.
Trích dẫn luật: NFPA 70ELuyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- A Class A GFCI intended to protect people trips at approximately what ground-fault current?
- What is the difference between a Class A (personnel) GFCI and a 30-milliampere 'equipment' ground-fault protection device?
- The arc flash boundary is best defined as the distance at which:
- Crossing the restricted approach boundary toward an exposed energized part requires:
- 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:
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