The continuous ampere rating of a switch or circuit breaker used as a disconnecting means for cranes and monorail hoists shall be not less than ____% of the combined short-time ampere rating of the motors, or less than ____% of the sum of the short-time ampere rating of the motors required for any single motion. A) 50 / 75 B) 80 / 100 C) 100 / 125 D) 125 / 175
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Answer: A
Article 610 of the 2017 NEC focuses on cranes and hoists. Part IV of this Article covers the requirements for disconnecting means. As per Sec. 610.33, “The continuous ampere rating of the switch or circuit breaker required by 610.32 shall not be less than 50% of the combined short-time ampere rating of the motors or less than 75% of the sum of the short-time ampere rating of the motors required for any single motion.”
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].