Stumped by the Code? NEC Requirements for Installing TC Cable

July 12, 2023

Answering your NEC questions

Mike Holt

Courtesy of www.MikeHolt.com

All questions and answers are based on the 2023 NEC.

Q: What are the conditions TC cable can be used and installed?

A: Section 336.10 lists the conditions that TC cable can be used and installed.

Type TC cable is permitted to be used:

(1) For power, lighting, control, and signaling circuits.

(2) In cable trays including those with mechanically discontinuous segments up to 1 ft.

(3) In raceways.

(4) In outdoor locations supported by a messenger wire.

(5) For Class 1 circuits in accordance with Art. 725.

(7) Between a cable tray and equipment if it complies with Sec. 336(10)(7).

(8) In wet locations where the cable is resistant to moisture and corrosive agents.

(9) In one- and two-family dwellings, Type TC-ER-JP cable is permitted for branch circuits and feeders where installed in accordance with Part II of Art. 334 for interior wiring, and Part II of Art. 340 for exterior wiring (see Figure).

Exception: Where Type TC cable is used to connect a generator and its associated equipment, the cable ampacity limitations of Sec. 334.80 and Sec. 340.80 do not apply.

Author’s Comment: The “ER” marking on Type TC-ER cable identifies it as suitable for exposed run use in accordance with UL. The “JP” marking on Type TC-ER-JP cable identifies it as suitable to be pulled through wood framing members because the cable has met the joist pull testing requirements of UL.

(10) Direct buried where identified for direct burial.

Q: Under what conditions can TC cable not be used and installed?

A: The conditions where TC cable cannot be used and installed are stated in Sec. 336.12.

Type TC cables are not permitted:

(1) Where exposed to physical damage.

(2) Outside a raceway or cable tray system, except as permitted in Sec. 336.10(4), Sec. 336.10(7), Sec. 336.10(9), and Sec. 336.10(10).

(3) Exposed to the direct rays of the sun, unless identified as sunlight resistant.

Q: How much can you bend TC cable?

A: According to Sec. 336.24, bends in Type TC cable must be made so the cable will not be damaged. Type TC cable without metal shielding must have a minimum bending radius as follows:

(1) Four times the overall diameter for cables 1 in. or less in diameter.

(2) Five times the overall diameter for cables larger than 1 in. but not more than 2 in. in diameter.

These materials are provided 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.