Overview

Heating cables are effective in distributing heat throughout a room, as they can adapt to any room size, shape, or requirements. However, they cannot be installed within walls without sufficient protection against mechanical and electrical stresses. NEC 2023 introduced a new Section 424.48, outlining the necessary requirements for such installations. This change aims to incentivize manufacturers to develop heating cables and cable sets suitable for wall installation and establish a standardized practice for safe installation inside walls.

Applying the 2023 Code

Heating cables are flexible cables designed to produce heat when an electric current flows through them. They serve various purposes, including preventing pipe freezing, de-icing roofs and gutters, and providing floor heating. Recently, they’ve gained popularity for room heating due to their ability to evenly distribute heat throughout the space. This heating method offers several advantages over traditional systems, including quiet operation, eco-friendliness, space-saving design, and cost-effectiveness. However, installing heating cables within walls for efficient room heating requires adequate protection against mechanical and electrical stresses. Previous NEC editions didn’t specify protection requirements for such installations. To address this gap, NEC 2023 introduced Section 424.48, detailing the necessary requirements for installing heating cables and cable sets within walls. Per Section 424.48, heating cables can only be installed in, on, or behind walls provided they are identified as suitable for such installations, are GFCI and AFCI protected, come with copper brain, metal sheath or other approved means of grounding, and are not installed more than 1.2m (4 ft) above the floor”. These changes will encourage equipment manufacturers to develop new heating products suitable for wall installation.

What’s New for the 2023 NEC?

The table below presents a comparison between the 2020 NEC and the 2023 NEC regarding Section 424.48.

2020 NEC

No reference to Heating cable installations can be found in NEC 2020.

2023 NEC

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.