Question 13038 of 731 · Texas Journeyman Electrician Exam
What is the maximum one-way length for a 120 volt circuit of 12 AWG copper (6,530 circular mils) carrying 16 A if voltage drop must not exceed 3 %?
Exactly one answer is correct.
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Correct answer to question 13038
- B: 57 ft
Explanation
Allowed drop is 3.6 V, and L = VD x CM / (2 x K x I) = 3.6 x 6,530 / (2 x 12.9 x 16) = 57 ft. Forgetting the factor 2 doubles the result to 114 ft.
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