National Electrical Installation Standards

Standards as High as Your Own

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Tuesday, October 9, 2018

Question:

Re: CQD answer published Wednesday, September 14, 2018 -Suspended Ceiling Luminaires 2

Good morning, I enjoy the Forum and all that you do.  I am not sure if in today's answer you misspoke or perhaps we have a different interpretation of 410.36(B).  As I understand it, the section covers ceiling systems used to support luminaires.  If the luminaire is supported independently, such as by wires on opposite corners, it is supported by the wires and not by the ceiling system.  As such, it is not required to secure the luminaire to the framing member.  In this case, in the event a fire fighter removes all or a portion of the ceiling grid in the course of fighting a fire, the luminaires would remain in place if unattached to the grid.  If attached, removing the grid would also bring down the luminaires.  Seismic concerns are also covered by this logic.  On the other hand, if the luminaire is supported solely by the grid, it must be secured to the grid per 410.36(B).

J Grant Hammett

A

Answer:

Hey J Grant thanks for your comment and we are glad you enjoy CQD. Proposal 18-32 was Accepted in Principle during the processing of the 1987 NEC and the words "so supported" were removed from the second sentence of 410-16(c). The Panel Comment was " The Panel agrees that all Fixtures within a ceiling system should be attached to that ceiling system."

Comment 18-23 suggested adding an exception to not require fastening to a suspended ceiling where the "fixtures" are supported directly to the structural ceiling. That comment was rejected with the supporting wording: "It is the Panel's intent to require fixtures otherwise supported to be fastened to the grid."

It is understandable how your interpretation can be made with the existing wording. Consider submitting a Public Input for the 2023 NEC in 410.36(B) to improve the wording so it is clear the rule applies whether or not the suspended ceiling is the only means of support or not.

See tomorrows answer for even more information about luminaires in suspended ceilings.

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