Calculations第 11 / 110 题
For a 200-A dwelling service using the 83% conductor allowance, what is the smallest copper ungrounded conductor (75 C) permitted for the main power feeder?
a.#3/0 AWG
b.#1/0 AWG
c.#2/0 AWG
d.#4/0 AWG
解析
200 A x 0.83 = 166 A required ampacity. At 75 C, #2/0 Cu is rated 175 A, which satisfies 166 A, so #2/0 is the smallest permitted.
法律依据: 2023 NEC 310.12免费刷完整 110 道题库 — 无需注册。
同考点相关题目
- A dwelling has four fastened-in-place appliances (dishwasher, disposal, water heater, compactor) totaling 6,000 VA. What is the demand load after applying the fastened-appliance demand factor?
- A dwelling's total calculated load is 24,000 VA on a 240-V, single-phase service. What is the calculated service current?
- Using the 75 C column, what is the smallest copper conductor rated to carry a 100-A service load?
- An electric range has a Column C demand of 8,000 VA. Using the 70% neutral demand for ranges, what is the range contribution to the feeder neutral load?
- From the motor full-load current table, what is the full-load current of a 25-HP, 480-V, three-phase induction motor?
- A single continuous-duty motor has a table full-load current of 34 A. What minimum conductor ampacity is required for its branch circuit?