Thiết bị & Hệ thốngCâu 290 / 521
The equipment grounding conductor for a motor branch circuit is sized based on what, per NEC 250.122?
a.The motor horsepower
b.The rating of the branch-circuit short-circuit/ground-fault protective device
c.The full-load current only
d.The conductor insulation temperature
Giải thích
NEC 250.122 sizes the equipment grounding conductor from Table 250.122 using the rating of the overcurrent device (the branch-circuit short-circuit/ground-fault device) ahead of the equipment. Horsepower, FLC alone, and insulation rating do not directly set the EGC size.
Trích dẫn luật: 2023 NEC §250.122Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- NEC 450.9 requires that transformer ventilation openings be arranged so that they:
- A feeder supplies three 460 V, three-phase motors: 25 HP (34 A), 15 HP (21 A), and 10 HP (14 A). Per NEC 430.24, what minimum feeder ampacity is required?
- Per NEC 430.62, the maximum feeder overcurrent device for several motors equals the largest branch-circuit protective device rating plus the sum of the other motors' FLCs. If the largest motor's branch device is 90 A and the other motors' FLCs total 35 A, what is the maximum feeder device?
- Per NEC Table 430.250, what is the full-load current of a 7.5 HP, 230 V, three-phase motor?
- For the 7.5 HP, 230 V motor (FLC 22 A), what minimum branch-circuit conductor ampacity is required by NEC 430.22?
- For the 7.5 HP, 230 V motor (FLC 22 A), what is the maximum nontime-delay fuse per Table 430.52 (300%)?
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