For power fuses installed in equipment operating at over 1,000V, their maximum voltage rating shall not be less than the maximum _______ voltage. Fuses having a minimum recommended operating voltage shall not be applied below this voltage.
A) circuit B) symmetrical C) asymmetrical D) none of the above
See the answer below.
Answer: A
Article 490 covers the general requirements for equipment operating at more than 1,000V, nominal. As specifically outlined in Sec. 490.21(B)(1)(3), “The maximum voltage rating of power fuses shall not be less than the maximum circuit voltage. Fuses having a minimum recommended operating voltage shall not be applied below this voltage.”
Owen is the owner and president of National Code Seminars and the holder of master electrician certifications in 46 states. He can be reached at [email protected].