Question 8064 of 790 · California General 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.
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 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.
More questions: Motors, HVAC, Generators and Transformers
- 8065With primary and secondary protection, what is the maximum secondary device rating for a transformer with a secondary current of 9 A or more?
- 8066A 45 kVA, 480 volt three-phase transformer has primary-only protection. What is the maximum standard primary breaker size?
- 8067What must be done regarding the ventilation of a transformer?
- 8068A 75 kVA dry-type transformer is installed indoors. What is the minimum separation from combustible material without a fire-resistant barrier?
- 8072Oil-insulated transformers installed indoors are generally required to be installed in what?
- 8074Secondary conductors leave a transformer and do not exceed 10 ft in length. What may they terminate in without protection at the secondary terminals?