Protecting exposed NM cable
Where exposed NM cable could be damaged, it must be protected by rigid or intermediate metal conduit, EMT, Schedule 80 PVC or another approved means. Where it passes through a floor, that protection must extend at least 6 in. above the floor.
What the code requires
Exposed NM cable must closely follow the surface of the building finish or run on running boards.
Where it could be physically damaged, the cable must be protected by rigid metal conduit, intermediate metal conduit, EMT, Schedule 80 PVC conduit, RTRC marked -XW, or another approved means. Where it passes through a floor, it must be enclosed in one of these, extending at least 6 in. (150 mm) above the floor.
In unfinished basements and crawl spaces, cable run at angles with joists may be fastened directly to the bottom edges of the joists only if it is at least two 6 AWG or three 8 AWG conductors. Smaller cable must go through bored holes or on running boards. Cable on an unfinished basement wall may be run in listed conduit or tubing, or protected under 300.4. The conduit needs a bushing or adapter, the jacket must extend through it into the box at least ¼ in., and the cable must be secured within 12 in. of where it enters the conduit.
New in 2023, the conduit or tubing must have a bushing or adapter where the cable enters and exits, to protect it from abrasion. A separate new rule, 334.19, requires the cable's outer jacket to extend at least ¼ in. past any clamp or cable entry.
On the job
- NM cable sleeved in PVC on garage walls with no bushing at the ends is a common correction, as is Schedule 40 PVC where Schedule 80 is required.
- Protective sleeves where cable passes through a floor must extend at least 6 in. above the floor.
What changed in 2023
The 2023 NEC added the bushing or adapter requirement at the ends of protective conduit, and a new 334.19 requiring the cable jacket to extend at least ¼ in. past a clamp or cable entry.
Related sections
- NEC 300.4: Protecting cables from nails and screws
- NEC 334.19
- NEC 334.17
- NEC 334.30: Stapling and supporting NM cable
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Kyle Robert Anderson KBC Electric · CSLB #1073066 · C-10 Electrical · Licensed since 2021