Kiểm tra & Khắc phục sự cốCâu 493 / 521
The 2023 NEC added a requirement on how terminations must be tightened when the manufacturer provides a torque value. What does it require?
a.Tighten firmly by hand until the conductor cannot be pulled out
b.Use any screwdriver and tighten an extra quarter-turn past snug
c.Torque is only required on conductors 4 AWG and larger
d.Tighten to the manufacturer's specified torque using a calibrated torque tool
Giải thích
Where a manufacturer provides a torque value, the connection must be made with a calibrated torque tool (torque screwdriver/wrench) to that value, since both under- and over-torquing cause failures and heating. Hand-tight or 'quarter-turn' methods (a, b) are not the code rule, and the requirement is not limited to large conductors (c).
Trích dẫn luật: 2023 NEC §110.14(D)Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
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