Arc flash hazard

Code Q&A: Labeling Requirements for Service Equipment

Aug. 17, 2017
NEC Labeling Requirements for Service Equipment

Underlined text indicates a change in the rules for the 2017 NEC.

Q.  Does the Code have service equipment fault current labeling requirements for services rated 1,200A and more?

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A.  Yes. Service equipment rated 1,200A or more must have a field or factory installed label containing the following details and have sufficient durability to withstand the environment [110.16(B)]:

(1)  Nominal system voltage

(2)  Available fault current at the service overcurrent protection device

(3)  Clearing time of the service overcurrent protection device based on the available fault current at the service equipment

(4)  Date the service equipment available fault current label was installed

Exception: Service equipment labeling isn’t required if an arc‑flash label in accordance with NFPA 70E, Standard for Electrical Safety in the Workplace, [see Note 3] is applied.

Note No. 1: NFPA 70E, Standard for Electrical Safety in the Workplace, provides guidance in determining the severity of potential exposure, planning safe work practices, arc-flash labeling, and selecting personal protective equipment.

Note No. 3: NFPA 70E, Standard for Electrical Safety in the Workplace provides specific criteria for developing arc-flash labels, such as nominal system voltage, incident energy levels, arc-flash boundaries, and selecting personal protective equipment.

These materials are provided to us by Mike Holt Enterprises in Leesburg, Fla. To view Code training materials offered by this company, visit 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.

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