Metallic vs. Nonmetallic boxes

[dcspector]

I have noticed in UL White book pg. 257 (QCIT) addresses metallic boxes installed in fire rated assemblies....the boxes are intended to be fastened to the studs. However, pg. 258 (QCMZ) nonmetallic boxes this installation is not mentioned. In summary, one can install a nonmetallic 'old work" box in a rated assembly? Did I miss something here?

 

[raider1]

It also says:

"The boxes are Classified for use in certain fire resistive designs when installed in accordance with the details described for each Classified company"

So I would say that 110.3(B) would apply and you would have to install the box in accordance with its installation instructions for the type of fire rated assembly it is being installed in.

I am not aware of any old work boxes that are listed for use in a fire rated assembly.

Metal boxes need not be listed for use in a fire rated assmenbly that is why there is a more prescriptive description of how to use a metal box in a fire rated assembly.

Chris

 

[rexowner]

Nonmetallic is fine if so rated. Two examples below,
the plastic box that attaches to the studs is fire
rated, and the one with ears isn't - I'm not
sure that's the only reason why.

Carlon Blue Old Work Boxes are "not UL Classified for Fire
Resistance." (ears)

Arlington One-box non-metallic (new or old work) have
a two hour fire rating. (internal screws)

 

[dcspector]

I am not aware of any old work boxes that are listed for use in a fire rated assembly.



Chris

Thanks Chris! I was not either. Thought I was going nuts! What I have is a corridor, occupancy A to R-2 with 2hr rated assembly and EC installed round Carlon "old work" boxes for small pendant luminaires. I am "assuming" (don't know yet) at this point they weigh less than 6 pounds.

 

[raider1]

Thanks Chris! I was not either. Thought I was going nuts! What I have is a corridor, occupancy A to R-2 with 2hr rated assembly and EC installed round Carlon "old work" boxes for small pendant luminaires. I am "assuming" (don't know yet) at this point they weigh less than 6 pounds.

Your welcome.

The Carlon round Old work boxes are not listed to hang a fixture from, in a ceiling. Here is what they say in the FAQ:

"The B618R is a round old work outlet box and is not listed for fixture support in
the ceiling. Only approved ceiling boxes are allowed to support fixtures in the
ceiling. These boxes will be permitted to support a minimum weight of 50
pounds. The B618R can be used in the ceiling as a junction box. Do not hang a
fixture from it since it relies on the strength of the ceiling itself."

Chris

 

[Dennis Alwon]

Arlington makes a plastic box F101 that is a 2 hr. plastic fire rated box. Here is the pic

 

[raider1]

Arlington makes a plastic box F101 that is a 2 hr. plastic fire rated box. Here is the pic

Are those boxes designed for the purpose of supporting a ceiling mounted luminaire?

If you are using the box to support a ceiling mounted luminaire the box must be designed for the purpose. (See 314.27)

Chris

 

[Dennis Alwon]

Are those boxes designed for the purpose of supporting a ceiling mounted luminaire?

If you are using the box to support a ceiling mounted luminaire the box must be designed for the purpose. (See 314.27)

Chris

This particular box is not rated for ceiling but I was responding to this part of your post

I am not aware of any old work boxes that are listed for use in a fire rated assembly.

Also in a week or two Arlington will have a fire rated old work box that is rated for fixtures. The part # is FDN23. I am waiting for a fax of it as I type

 

[raider1]

This particular box is not rated for ceiling but I was responding to this part of your post




Also in a week or two Arlington will have a fire rated old work box that is rated for fixtures. The part # is FDN23. I am waiting for a fax of it as I type

Thanks, I have seen these boxes but when I posted I wasn't thinking of these as "old work boxes" but you are right they work really good in old work situations.

What I should have said is that I am not aware of any old work boxes that are listed for use in a fire rated assembly that use the sheetrock for sole support.

Chris