An toànCâu 434 / 521
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?
a.2 feet
b.2½ feet
c.3 feet
d.4 feet
Giải thích
For nominal voltages of 151-600V, Condition 1 requires a minimum clear working-space depth of 3 feet in front of the equipment. The 3½- and 4-foot figures apply to Conditions 2 and 3 in that voltage range, and 2 or 2½ feet is never permitted for this equipment.
Trích dẫn luật: 2023 NEC §110.26Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- An energized electrical work permit is generally required when:
- 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:
- A 480V panel is installed so the worker stands between two energized sections with exposed live parts on both sides of the working space (Condition 3). What minimum working-space depth is required?
- The clear working space in front of a panelboard must be at least how wide and how high?
- The 'dedicated equipment space' above an indoor panelboard or switchboard:
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