Article 310.4A of the National Electrical Code (NEC)Purpose

Article 310.4A requires that conductors entering a raceway, enclosure, or other electrical equipment be protected from damage due to vibration or physical abuse.

In Detail



Applies to

Conductors in enclosures, raceways, or electrical equipment where they are subject to: Vibration Abrasion Other physical damage

Protection Measures

Conductors must be secured to prevent movement or abrasion. Approved cable clamps, straps, or fittings must be used for securement. Busbars or other conductors must be braced to resist vibration. Where conductors enter a raceway or enclosure, bushings must be used to protect them from sharp edges or abrasion.

Exceptions

Conductors that are not subject to vibration or physical damage. Conductors that are already protected by other means, such as flexible metal conduit or flexible cord. Conductors in combination with power distribution blocks.

Situations Where Article 310.4A Applies

Electrical panels and enclosures Raceways and conduit systems Switchboards and switchgear Motor control centers Industrial and commercial equipment* Generators and other rotating machinery

Note:

If an inspector incorrectly issued a violation based on Article 310.4A, you can provide evidence demonstrating that the conductors were not subject to vibration or physical damage. You can also request a reinspection from the inspector or a higher authority. Flag for review