Code Quiz of Day

Rating of Supply Conductors for X-Ray Equipment

June 30, 2015

The ampacity of supply branch-circuit conductors and the overcurrent protective devices for X-ray equipment shall not be less than _____.

Mike Holt

The ampacity of supply branch-circuit conductors and the overcurrent protective devices for X-ray equipment shall not be less than _____.

a) 50% of the momentary rating
b) 100% of the long-term rating
c) the larger of a or b
d) the smaller of a or b

See answer and applicable Code reference

The correct answer is: c) the larger of a or b

Article 660 covers all X-ray equipment operating at any frequency or voltage for industrial or other nonmedical or nondental use. As noted in Sec. 660.6(A), "The ampacity of supply branch-circuit conductors and the overcurrent protective devices shall not be less than 50% of the momentary rating or 100% of the long-term rating, whichever is greater."

About the Author

Mike Holt

Mike Holt is the owner of Mike Holt Enterprises (www.MikeHolt.com), one of the largest electrical publishers in the United States. He earned a master's degree in the Business Administration Program (MBA) from the University of Miami. He earned his reputation as a National Electrical Code (NEC) expert by working his way up through the electrical trade. Formally a construction editor for two different trade publications, Mike started his career as an apprentice electrician and eventually became a master electrician, an electrical inspector, a contractor, and an educator. Mike has taught more than 1,000 classes on 30 different electrical-related subjects — ranging from alarm installations to exam preparation and voltage drop calculations. He continues to produce seminars, videos, books, and online training for the trade as well as contribute monthly Code content to EC&M magazine.