National Electrical Installation Standards

Standards as High as Your Own

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Wednesday, October 9, 2019

Question:

Re: CQD answer published Thursday, October 3, 2019 - Suspended Ceiling Luminaires

Along with this question. I have a question about the MC cable from troffer fixture to the next fixture. We were asked to mount a support wire for this MC cable independent from the ceiling supports. In the past we used the CADDY clips that were installed on the same wires that also support the ceiling "T" Bars. Our inspector is asking for separate wires to the ceiling for MC cable support. Most of the cables were 10'-12' long. The Suspended ceiling is 9' and the roof trusses are about 18'-20'. We know they are requiring the Earthquake Clips to secure the fixture to the "T"-Bars.

Tom Inman
A

Answer:

Hey Tom thanks for your related question. The inspector is correct. Support wires that are in addition to the ceiling grid support wires (and secured at both ends) can be used as the support for wiring systems as stated in the second sentence of 300.11(B). The independent (additional) support wires must be distinguishable as stated in the last sentence of 300.11(B)(2). The exception to 300.11(B)(2) allows the ceiling support system to be used - only if the ceiling system manufacturer has instructions of how to do that.

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