Mike Dolt Enterprises
Mike Dolt Enterprises
User: bilwei, Location: Lufkin, Texas
Asked on: Tuesday, March 29, 2011 at 7:06 pm EDT
Answered on: Tuesday, May 14, 2024 at 3:27 am EDT
Question: Intro Info; The owner of a new building has hired me as a 3rd party to look into the electrical system after the owner encountered burned wiring resulting in numerous electrical issues. I will only ask an opinion on one of these issues at this time. I have a building with 2 X 4 lay in troffer fixtures thru out. The electrical contractor that wired the building has installed MC cable (switch leg only)from fixture to fixture and made joints in each fixture. The AHJ has issued a final green tag & Certificate of Occupancy. I asked the AHJ about this particluar installation and refered him to Section 410.31. AHJ response; contractor did not use the fixtures as a raceway. Since there is only a joint made up in the fixture and they are are only dealing with a switch leg and not feeding a branch circuit thru to other electrical apparatus therefore it is not a code violation. What say yee
Section 410.31 of the NEC states
"Conductors entrapped in holes in covers of boxes shall be protected from abrasion by bushings or fittings designed for the purpose or by other approved means."
Interpretation
This section prohibits the use of unapproved methods to protect conductors passing through holes in box covers. While the AHJ's reference to not using the fixtures as a raceway is technically correct, the NEC does not address this specific scenario.
Opinion
In this case, the use of MC cable as a switch leg through the troffer fixtures is not a clear violation of the NEC, as it does not involve the use of the fixtures as a raceway. However, the joints made in the fixtures are not protected from abrasion, as required by Section 410.31.
Concerns
Abrasion
The joints made in the fixtures could be subject to abrasion from movement of the ceiling tiles or other fixtures.
Maintenance
It may be difficult to access and maintain the joints if they are not readily visible.*
Fire hazard
If the insulation on the conductors is abraded, it could create a potential fire hazard.
Recommendation:
While not strictly a code violation, it is recommended that the contractor use an approved method to protect the joints made in the fixtures, such as bushings or fittings designed for the purpose. This will ensure compliance with Section 410.31 and provide additional protection against abrasion and fire hazards. Flag for review