Code Q&A: Where Can You Not Use Flexible Cords and Flexible Cables?

Feb. 10, 2022

Test your knowledge of the NEC.

Courtesy of www.MikeHolt.com.

Based on the 2020 NEC.

Q. The NEC does not permit flexible cords and flexible cables to be used for what purposes?

See answer below.

A. Unless specifically permitted in Sec. 400.10, flexible cords, flexible cables, cord sets (extension cords), and power‑supply cords are not permitted for the following (Sec. 400.12):

(1) Flexible cords, flexible cables, cord sets (extension cords), and power‑supply cords are not permitted to be a substitute for the fixed wiring.

(2) Flexible cords, flexible cables, cord sets (extension cords), and power-supply cords are not permitted to be run through holes in walls, structural ceilings, suspended or dropped ceilings, or floors (Fig. 1).

(3) Flexible cords, flexible cables, cord sets (extension cords), and power‑supply cords are not permitted to be run through doorways, windows, or similar openings.

(4) Flexible cords, flexible cables, cord sets (extension cords), and power‑supply cords are not permitted to be attached to building surfaces.

Exception to (4): Flexible cords and flexible cables used for temporary wiring [Sec. 590.4] may be attached to building surfaces.

(5) Flexible cords, flexible cables, cord sets (extension cords), and power‑supply cords are not permitted to be concealed by walls, floors, or ceilings, or located above suspended or dropped ceilings (Fig. 2).

Exception to (5): Flexible cords, flexible cables, and power‑supply cords are permitted if contained within an enclosure for use in other spaces used for environmental air as permitted by [Sec. 300.22(C)(3)].

(6) Flexible cords, flexible cord sets (extension cords), and power‑supply cords are not permitted to be installed in raceways, except as permitted by Sec. 400.17 for industrial establishments where the conditions of maintenance and supervision ensure that only qualified persons will service the installation.

(7) Flexible cords, flexible cord sets (extension cords), and power‑supply cords are not permitted where they are subject to physical damage.

Author’s Comment: It remains unclear how the uses not permitted can apply to cord sets and power-supply cords since they are not included in the scope of Art. 400.

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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.