Code Q&A: Cord- and Plug-Connected Equipment

Sept. 6, 2012

Your most pressing National Electrical Code (NEC) questions answered

Q. What is the Code limitation for sizing circuits that supply cord- and plug-connected equipment?

A. Cord- and plug-connected equipment not fastened in place, such as a drill press or table saw, must not have an ampere rating more than 80% of the branch circuit rating [210.23(A)(1)].

However, UL and other testing laboratories list portable equipment (such as hair dryers) up to 100% of the circuit rating. The NEC is an installation standard, not a product standard, so it can't prohibit this practice. So there's really no way to limit the load to 80% of the branch-circuit rating if testing laboratories permit equipment to be listed for 100% of the circuit rating.

Equipment fastened in place (other than luminaires) must not be rated more than 50% of the branch-circuit ampere rating if this circuit supplies luminaires, receptacles, or both [210.23(A)(2)]. For example, can a whole house (central) vacuum motor rated 13A be installed on an existing 20A circuit that supplies more than one receptacle outlet? The answer is no. An individual 15A or 20A branch circuit will be required in this situation.

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.