Question 13122 of 749 · Maryland Journeyperson Electrician Exam
A 9 kW, 480 volt, three-phase resistive heater is a continuous load. What is the minimum standard overcurrent device rating?
Exactly one answer is correct.
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Correct answer to question 13122
- B: 15 A
Explanation
Current is 9,000 / (480 x 1.732) = 10.8 A, and 10.8 x 1.25 = 13.5 A, so the next standard size is 15 A. Forgetting 1.732 gives 18.75 x 1.25 = 23.4 A and leads to 25 A.
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