Branch Circuits & FeedersCâu 2 / 120
For that same 24-ampere continuous load, what is the minimum size copper branch-circuit conductor, assuming 75 degrees C terminations and THWN insulation?
a.12 AWG
b.10 AWG
c.8 AWG
d.14 AWG
Giải thích
The conductor must carry at least 125 percent of the continuous load, or 30 A. In the 75 degrees C column of Table 310.16, 12 AWG copper is only 25 A, so it fails; 10 AWG copper is 35 A and is adequate, and 240.4(D) still allows a 30 A device on 10 AWG. Choosing 8 AWG is oversized for the minimum asked, and 14 AWG is limited to 15 A.
Trích dẫn luật: 2023 NEC §210.19(A)Luyện miễn phí toàn bộ 120 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- A 208-volt, single-phase branch circuit supplies a continuous load of 24 amperes. What is the minimum standard overcurrent device rating permitted?
- Six current-carrying 12 AWG THHN copper conductors are installed in a single EMT run at a 30 degrees C ambient. What is the adjusted ampacity of each conductor before termination limits are applied?
- Four current-carrying 8 AWG THWN-2 copper conductors run in a raceway through a 48 degrees C ambient. What is the adjusted ampacity of each conductor?
- A 120-volt circuit carries 20 amperes through 12 AWG copper (6,530 circular mils) to a load 100 feet away. Using K = 12.9, what is the approximate voltage drop?
- A 480-volt, three-phase feeder carries 40 amperes 250 feet using 6 AWG copper (26,240 circular mils). Using K = 12.9, what is the approximate voltage drop?
- A 120-volt branch circuit must carry 12 amperes 120 feet with voltage drop held to 3 percent. Using K = 12.9 for copper, what is the smallest conductor that meets the target?
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