Branch Circuits & Feeders第 3 / 120 题
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?
a.25 amperes
b.20 amperes
c.22.5 amperes
d.24 amperes
解析
Start in the 90 degrees C column of Table 310.16, where 12 AWG THHN is 30 A, then apply the adjustment factor for 4 through 6 current-carrying conductors, which is 80 percent: 30 A x 0.80 = 24 A. The 22.5 A answer wrongly starts from the 75 degrees C value of 25 A, 25 A applies no adjustment at all, and 20 A is simply the 60 degrees C table value.
法律依据: 2023 NEC §310.15(C)(1)免费刷完整 120 道题库 — 无需注册。
同考点相关题目
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