Article 424 Fixed Electric Space-Heating Equipment
424.48 Installation of Cables in Walls. Unless prohibited by 424.38(B), heating cables and cable sets shall be permitted to be installed in, on, or behind walls provided all of the following are met:
(1) Heating cables and cable sets shall be identified as suitable for installation in, on, or behind walls.
(2) Heating cables and cable sets shall be GFCI protected.
(3) Grounding means, such as copper braid, metal sheath, or other approved means, shall be provided.
(4) Heating cables and cable sets shall be AFCI protected.
(5) Heating cables and cable sets shall be permitted to be installed no more than 1.2 m (4 ft) above the floor.
This requirement shall become effective January 1, 2026.

Material taken from the National Electric Code. is reprinted with permission from NFPA 70., 2023 edition. National Electrical Code®, Copyright 2022, National Fire Protection Association, Quincy, MA. All rights reserved.