Wood Ceilings & Pendant Light

[macmikeman]

When I install pendants against wood such as glue lam beams and the like I use these-
from Thomas and Betts. They come in white, ivory, and brown. Plastic.

 

[Dennis Alwon]

When I install pendants against wood such as glue lam beams and the like I use these-
from Thomas and Betts. They come in white, ivory, and brown. Plastic.

Yes but they are ugly especially when there is a chrome canopy or brass. Sounds like Mac is the only one who heard of this rule.

 

[Strathead]

This code makes sense though. It is kind of an extension of the code (which I can't find right now) that requires outlet boxes to be flush or protruding. I see what I consider a mistake in the wording of 314 though. That being that it shouldn't just be luminaires. What about ceiling fans, for example? These should certainly fall under the same restrictions, if there is a combustion issue.

 

[Dennis Alwon]

This code makes sense though. It is kind of an extension of the code (which I can't find right now) that requires outlet boxes to be flush or protruding.

314.20 and I agree it makes total sense

I see what I consider a mistake in the wording of 314 though. That being that it shouldn't just be luminaires. What about ceiling fans, for example? These should certainly fall under the same restrictions, if there is a combustion issue.

Time for a code proposal...:thumbsup:

 

[Dennis Alwon]

I don't think there is a clear answer to be found at the moment,

But why is gypsum allowed to be held back 1/4" If it were considered combustible then that would not be allowed.

Many years ago we talked about the flash point of paper (arguably 451?F) which came up because I said that it would be non compliant to leave a note on paper in an outlet box. I finally conceded.

 

[Gregg Harris]

But why is gypsum allowed to be held back 1/4" If it were considered combustible then that would not be allowed.

Many years ago we talked about the flash point of paper (arguably 451?F) which came up because I said that it would be non compliant to leave a note on paper in an outlet box. I finally conceded.

Dennis I do not believe the requirement is intended for pendant lighting and it appears that it is being addressed for clarity. Adding at the end of 314.20 if required by 410.23 for the next code cycle.

The insulation required by UL listed products years ago is what stimulated 314.20. The insulation eliminates the requirement
Proposal to Change 2011 NEC 18-69 Log #1594 NEC-P18

Final Action: Accept
(410.23)

________________________________________________________________

Submitter: Edward Joseph, Underwriters Laboratories Inc.
Recommendation: Revise text to read as follows:
410.23 Covering of Combustible Material at Outlet Boxes. Any combustible wall or ceiling finish exposed between the edge of a luminaire canopy or pan and an outlet box, having a surface area of 1160 mm2 (180 in2) or more, shall be covered with noncombustible material.
Substantiation: This proposed revision to Section 410.23 aligns the requirements in the NEC and ANSI/UL1598 for ?listed? luminaires and serves to further support Section 410.6 which requires the installation of ?listed? luminaires.
Questions have been raised by inspection authorities concerning Section 410.23 as to whether or not there is a need to additionally cover combustible mounting surfaces as defined within in the Article, when installing a ?listed? ceiling mounted or wall mounted canopy style luminaire that does not have a back-plate or back-cover.
Based on explanatory notes in 2008 NEC handbook, Section 410.23 was written to address overheating of combustible surfaces. The note states the following: ? Luminaires must be designed and installed not only to prevent overheating of conductors but to prevent overheating of adjacent combustible wall or ceiling finishes. Hence, it is required that any combustible finish between the edge of a luminaire canopy and an outlet box be covered with a noncombustible material or luminaire accessory. See 314.20 for the requirements covering combustible finishes. Where luminaires are not directly mounted on outlet boxes, suitable outlet box covers are required.?
Listed luminaires are evaluated to the requirements of the Standard for Luminaires, ANSI/ UL1598. Based on requirements in the ANSI/UL 598 standard, ?listed? canopy style surface or ceiling mounted luminaires do not require a back-plate or back-cover provided the total area of the surface being covered by the canopy is less than 1160 mm2 (180 in2). In addition, these ?listed? canopy style luminaires are evaluated based on requirements in the standard to ensure that temperatures on wall or ceiling surfaces on which the luminaire is mounted do not exceed 90 degrees centigrade. This 90 degrees centigrade limit, is the limit that both the luminaire standard and the NEC assigns for continuous heating of combustible materials. These requirements have been in effect for ?listed? luminaires for several decades.
In summary, the requirements for ?listed? luminaires fulfills the requirement of Section 410.23 and therefore, does not warrant the need for additional protection of a combustible mounting surface beyond what the ?listed? luminaire provides. This proposed revision to Section 410.23 will provide the needed clarification.
Panel Meeting Action: Accept
Number Eligible to Vote: 11
Ballot Results: Affirmative: 11

 

[Dennis Alwon]

Very interesting. Now why is 180 square inches the cutoff. I didn't think the issue was just heat since we have to protect walls where boxes are set back from combustibles. This new proposal doesn't make total sense to me

 

[Gregg Harris]

Very interesting. Now why is 180 square inches the cutoff. I didn't think the issue was just heat since we have to protect walls where boxes are set back from combustibles. This new proposal doesn't make total sense to me

The 180 square inches of protection is equal to the circumference of the canopy,if it was larger than 14 'nches no protection is required. The further away the less heat involved

 

[Dennis Alwon]

I understand what the sq. inches is about- it can also be a rectangular canopy. I don't understand the logic with 314.20

 

[macmikeman]

The other thing you can do, which I use when rewiring old houses around here that have tongue and groove ceilings, usually dried out termite chewed wood... , is to go get some of those "medallions" from the Home Depot to put between the fixtures and the wood ceilings. They have a knockout in the center sized to fit perfectly over a 3" fixture box.

 

[Gregg Harris]

I understand what the sq. inches is about- it can also be a rectangular canopy. I don't understand the logic with 314.20

These are both the same

312.3 Position in Wall. In walls of concrete, tile, or other noncombustible material, cabinets shall be installed so that the front edge of the cabinet is not set back of the finished surface more than 6 mm (? in.). In walls constructed of wood or other combustible material, cabinets shall be flush with the finished surface or project therefrom.
314.20 In Wall or Ceiling. In walls or ceilings with a surface of concrete, tile, gypsum, plaster, or other noncombustible material, boxes employing a flush-type cover or faceplate shall be installed so that the front edge of the box, plaster ring, extension ring, or listed extender will not be set back of the finished surface more than 6 mm (1/4 in.).
In walls and ceilings constructed of wood or other combustible surface material, boxes, plaster rings, extension rings, or listed extenders shall be flush with the finished surface or project therefrom.

 

[Dennis Alwon]

If you do the math a standard 5 " canopy is 19.625 sq. in

 

[jumper]

Asked 4 electricians at work, so including me- not one of five people knew this section!!:slaphead:

Nice thread Dennis.:thumbsup:

 

[Dennis Alwon]

Asked 4 electricians at work, so including me- not one of five people knew this section!!:slaphead:

Nice thread Dennis.:thumbsup:

TY

I was thinking about this last night and many wall sconces on the outside of many homes would be an issue. Why doesn't the manufacturer just put a metal backing on the canopy or fixture. Fixtures like the one below on siding is a problem.

 

[guschash]

I don't think I ever saw insulation that was sold just for that purpose. Guess I need to get for my truck also.