Question 13108 of 749 · Maryland Journeyperson Electrician Exam
A 15 kVA, single-phase transformer with a 240 volt primary is protected on the primary side only. Which statement about its primary current is correct?
Exactly one answer is correct.
You got of questions right. Here on the question pages nobody remembers which ones you got wrong. The trainer saves your progress and asks the mistakes again until they stick.
Or free: the 10 questions most people get wrong
Show solution
Correct answer to question 13108
- D: It is 62.5 A, so the 125 % primary rule applies
Explanation
Primary current is 15,000 / 240 = 62.5 A. Because that is 9 A or more, primary-only protection uses 125 %; the 167 % and 300 % limits apply only to primary currents below 9 A and below 2 A.
More questions: Electrical Calculations
- 13109A branch circuit supplies a 36 A continuous load and nothing else. What is the minimum overcurrent device rating?
- 13110A 40 A continuous load is supplied with THWN copper conductors terminating on 75 °C rated equipment. What is the minimum conductor size?
- 13111A branch circuit supplies 30 A of continuous load and 20 A of noncontinuous load. What is the minimum standard overcurrent device rating?
- 13112What is the maximum continuous load permitted on a 20 A branch circuit protected by a standard (not 100 % rated) breaker?
- 13113What is the maximum continuous lighting load in volt-amperes on a 277 volt, 20 A branch circuit?
- 13114How many 277 volt LED luminaires drawing 0.75 A each may be connected to a 20 A branch circuit if they operate continuously?