This weeks post is about attaching ceiling wires to fixtures installed in grid type ceilings. I get calls all the time about having to attach wires to fixtures installed in grid type ceilings. For the record our electrical Code states that we have to “screw, clip, or rivet” the fixtures to the grid, that’s it! The hangers wires which are so routinely required, come from the manufacturers instruction for the particular type of ceiling grid. 99% of the time that these wires are required there are no ceiling grid details or manufacturers instructions that show these requirements, but are just someone’s interpretation of a UL standard or building code which may or may not be correct. I have heard story after story of how the Electrical contractor had to install these extra wires on the fixtures when in fact it is NOT an electrical Code requirement. Hanger wires on fixtures should be done by the person(s) responsible for the ceiling and only when they are needed (required).
Below you will find a memo sent out by Jeffrey A. Fecteau CBO, ECO a Senior Regulatory Engineer working for UL addressing fixtures installed in grid type ceilings. Jeff has always been helpful in solving problems that arise out in the field brought on by an inspector/contractor conflict. Also posted below you will find a FBC formal interpretation that went into effect November 12, 2015. This was sent out this week by Broward County Board of Rules and Appeals. This formal interpretation now puts the grid wire problem into the design professional and/or the manufacturers hands to solve. Hope this helps.
Memo from Jeffrey Fecteau
Over the years, I have been asked numerous times, where in the code is the requirement that slack wires are to be attached to grid supported luminaires? I have provided the following response;
NEC section 410.36(B) requires that the framing members of suspended ceiling systems that are used to support luminaires shall be securely fastened to each other and shall be securely attached to the building structure at appropriate intervals. Luminaires shall be securely fastened to the ceiling framing member by mechanical means such as bolts, screws, or rivets. Listed clips identified for use with the type of ceiling framing member(s) and luminaire(s) shall also be permitted.
The 2015 IBC section 808.1.1.1 requires that suspended acoustical ceiling systems shall be installed in accordance with the provisions of ASTM C 635 and ASTM C 636.
The additional support requirements come from the ceiling grid standard ASTM C636 (Standard Practice for Installation of Metal Ceiling Suspension Systems for Acoustical Tile and Lay-In Panels);
2.7 Ceiling Fixtures:
2.7.1 Mount fixtures installed in acoustical tile or lay-in panel ceilings in a manner that will not compromise ceiling performance.
2.7.2 Fixtures shall not be supported from main runners or cross runners if the weight of the fixture causes the total dead load to exceed the deflection capability of the ceiling suspension system. In such cases, the fixture load shall be supported by supplemental hangers within 6 in. [150 mm] of each corner, or the fixture shall be separately supported.
2.7.3 Fixtures shall not be installed so that main runners or cross runners will be eccentrically loaded except where provision is inherent in the system (or is separately provided for) to prevent undesirable section rotation or displacement, or both. In any case, runners supporting ceiling fixtures shall not rotate more than 2° after the fixture loads are imposed.
2.7.4 Where fixture installation would produce rotation of runners in excess of 2°, install fixtures with the use of suitable accessory devices. These devices shall support the fixture in such a manner that main runners and cross runners will be loaded symmetrically rather than eccentrically.
Additional seismic requirements may be located in Chapter 16, section 1613 of the IBC.
Attached you will find a ruling from Broward County Board of Appeals on this issue. This may be something that you would like to include in the code enforcement requirements of your jurisdiction either by ordinance or by policy.
Jeff Fecteau
Jeffrey A. Fecteau CBO, ECO
Senior Regulatory Engineer UL
Till next time be safe work safe
Jake