Wood Ceilings & Pendant Light

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Wood Ceilings & Pendant Light

  • I knew it was Code

    Votes: 0 0.0%
  • I did not Know It was Code

    Votes: 16 100.0%
  • I knew it and always make it compliant

    Votes: 0 0.0%
  • I knew it and never did anything about it

    Votes: 0 0.0%

  • Total voters
    16
  • Poll closed .
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Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
How many members have ever installed non combustible material between the canopy and the box when installing a pendant on a wood ceiling ?


314.25(B) Exposed CombustibleWall or Ceiling Finish. Where a luminaire canopy or pan is used, any combustible wall or ceiling finish exposed between the edge of the canopy or pan and the outlet box shall be covered with noncombustible material.
 
Last edited:

iwire

Moderator
Staff member
Location
Massachusetts
How many members have ever installed non combustible material between the canopy and the box when installing a pendant on a wood ceiling ?

IMO This section does not apply to pendent fixtures but to surface fixtures and I would be willing to bet that is the reason they always ship with fiberglass insulation on the back side.


New-Home-CO-Signature-Surface-Mount-Light.jpg


But to answer your question, no I was not aware of it.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
IMO This section does not apply to pendent fixtures but to surface fixtures and I would be willing to bet that is the reason they always ship with fiberglass insulation on the back side.


But to answer your question, no I was not aware of it.

It simple says fixture so why would it not apply to pendants-- I agree it seems silly but the reason in part is due to an arc--- at least according to the handbook
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
What materials did they use? Aluminum foil?

For surface fixtures, various combinations of foil, fiberglass and fiberboard. For pendant canopy I actually saw a chunk of wallboard once, but I suspect that was really there as a mechanical spacer to keep tightening the attachment crown nuts from bending the canopy.
 

Sierrasparky

Senior Member
Location
USA
Occupation
Electrician ,contractor
OK so how are we to comply. I don't know of anyone who makes a Listed product for this purpose. You can use those Arlingtion box extenders but they will not always cover the entire canopy.
As far as I know drywall is combustible.

Heck Around these parts I always run into fixtures being hung in a wood ceiling with no box. It's like the contractor thought that the box was only there to screw the fixture mounts to. I see all the time a fixture strap screwed directly to the wood ceiling , romex just poked through, no connector nothing. And sometime Aluminum to bat!
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I am shocked that this issue has not come up before. A friend who is study for his unlimited exam called me and questioned what it really meant. I had to admit it was a new one on me. I am sure I have violated this rule many times.

My thoughts were as Bob stated earlier - that it was meant for surface fixtures but it clearly states luminaires. Guess we will have to keep some insulation or something on the van.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
OK so how are we to comply. I don't know of anyone who makes a Listed product for this purpose. You can use those Arlingtion box extenders but they will not always cover the entire canopy.
As far as I know drywall is combustible.

Heck Around these parts I always run into fixtures being hung in a wood ceiling with no box. It's like the contractor thought that the box was only there to screw the fixture mounts to. I see all the time a fixture strap screwed directly to the wood ceiling , romex just poked through, no connector nothing. And sometime Aluminum to bat!

Drywall is considered non combustible however the paper on the back side is combustible. I am guessing that tin foil will do the trick.
 

Sierrasparky

Senior Member
Location
USA
Occupation
Electrician ,contractor
Drywall is considered non combustible however the paper on the back side is combustible. I am guessing that tin foil will do the trick.

I do not think that Drywall is considered NON combustable . It may have certain resistence , I would need to look that up further.Some sites say Limited combustable.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I do not think that Drywall is considered NON combustable . It may have certain resistence , I would need to look that up further.Some sites say Limited combustable.

Have you ever been turned down for your switch box being back 1/4" from the finished edge? That is because it is not combustible. If it were considered combustible then the box would need to be flush with the outer surface of the rock. Read 314.20

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.
 

Sierrasparky

Senior Member
Location
USA
Occupation
Electrician ,contractor
Drywall is considered non combustible however the paper on the back side is combustible. I am guessing that tin foil will do the trick.

Have you ever been turned down for your switch box being back 1/4" from the finished edge? That is because it is not combustible. If it were considered combustible then the box would need to be flush with the outer surface of the rock. Read 314.20
Nope,

However I bet that you can find somewhere in the NFPA that Drywall is not classified as non-combustable.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Drywall is considered non combustible however the paper on the back side is combustible. I am guessing that tin foil will do the trick.

I don't think there is a clear answer to be found at the moment, but there does seem to be a trend:

In regard to gypsum wallboard, the product's paper facing prevents it from passing ASTM E 136. However, because it does have a demonstrated ability to perform in fire rated assemblies, the NFPA has placed it in a special classification called limited-combustible. This category distinguishes gypsum wallboard from other, more highly combustible products. To qualify as limited-combustible, a material must have a noncombustible structural base or core, a surface less than 1/8 in. (0.3 cm) thickness and a flame-spread rating of 50 or less.


This last requirement can be confusing because the three national model building codes, (ICBO's Uniform Building Code, SBCCI's Standard Building Code and BOCA's National Building Code), all allow composite materials that meet the NFPA's definition of limited-combustible, to be classified as noncombustible.
 

kwired

Electron manager
Location
NE Nebraska
Nope,

However I bet that you can find somewhere in the NFPA that Drywall is not classified as non-combustable.

You ever thrown drywall into a fire? The paper on the surface will burn off but the gypsum inside just turns to powder if left in the fire long enough, but it never burns. I guess like most anything else, if you get it hot enough it will burn.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
You ever thrown drywall into a fire? The paper on the surface will burn off but the gypsum inside just turns to powder if left in the fire long enough, but it never burns. I guess like most anything else, if you get it hot enough it will burn.

The only reason that it is not noncombustible is that the paper will burn. But as long as the flame spread caused by that paper is slow enough, NFPA is saying that for many purposes it is acceptable, and so they made a special category for it.
 

kwired

Electron manager
Location
NE Nebraska
The only reason that it is not noncombustible is that the paper will burn. But as long as the flame spread caused by that paper is slow enough, NFPA is saying that for many purposes it is acceptable, and so they made a special category for it.

And lining wood with foil or other thin walled metal with no thermal insulation will keep the wood from burning if there is a heat source on the other side of the metal:happyno:.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
And lining wood with foil or other thin walled metal with no thermal insulation will keep the wood from burning if there is a heat source on the other side of the metal:happyno:.
+1
:happyyes: If the sheet metal or foil is not touching the wood, it will act to reduce radiated heat and will spread the heat from any point source out over a wider area so that it is less likely to start a fire, but that is as much as it can do. It is pretty easy to burn things in a metal pan over a hot fire.
A metal heat shield separated from a combustible wall surface by spacers will do a good job as long as air can circulate behind it. But attaching it firmly to the wall will just keep you from seeing the char marks until there is a fire. :happysad:
 
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