Q. How is the conductor ampacity for Type MC cable determined per the NEC?
See the answer below.
This answer is based on the 2017 NEC.
A. Conductor ampacity is calculated on the 90°C insulation rating of the conductors; however, the conductors must be sized to the termination temperature rating in accordance with Sec. 110.14(C)(1) [330.80].
These materials are provided to us by Mike Holt Enterprises of Leesburg, Fla. To view additional Code training materials offered by this company, visit http://www.mikeholt.com/code.
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.