Question 8064 of 844 · Washington 01 Journey Level Electrician Exam
A transformer rated 1000 volts or less has both primary and secondary protection. What is the maximum primary device rating?
Exactly one answer is correct.
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Correct answer to question 8064
- D: 250 percent of rated primary current
Explanation
Table 450.3(B) allows the primary device to be rated up to 250 percent of the primary current when secondary protection is also provided. The secondary device is then normally limited to 125 percent for secondary currents of 9 A or more.
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