Question 13046 of 749 · Maryland Journeyperson Electrician Exam
What is the allowable ampacity of 6 AWG THHN copper (90 °C column) with three current-carrying conductors in a raceway at an ambient temperature of 40 °C?
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Correct answer to question 13046
- B: 68.3 A
Explanation
Table 310.16 gives 75 A for 6 AWG copper in the 90 °C column, and the 30 °C based correction factor for 36 to 40 °C in that column is 0.91: 75 x 0.91 = 68.3 A. Using the 75 °C value with its 0.88 factor (65 x 0.88) gives 57.2 A.
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