PVC Through Fire Rated Ceiling

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jetlag

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Eatonton, Georgia
I plan to install a surface mounted panel box on a residential garage interior masonry wall . There are dwelling rooms above the ceiling so the ceiling in the garage must have 5/8" type x drywall . My question is can I use sch 40 rigid PVC to provide a sleeve up to through the ceiling to bundle the NM cables ? Also how do you figure the 40 % fill for the NM cables ? Do you just measure them and estimate the cross section areas ? I don't see any tables for conduit fill for cables with 3 conductors . Will I have to use Rigid Metallic or EMT because of the fire rating ?
 
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NM is not rated for installation in conduit !........Any penetrations
in to \ thru the 5/8" gypsum would need to be reviewed by the
AHJ and approved BEFORE installing, ...ANYTHING !!

What codes are in place in your location ?......Have you discussed
your application with the local BO ?

Your application is not governed by the electrical codes, but
rather, the locally adopted Residential code [ if there are any ].

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Thanks for reply

Thanks for reply

NM can be installed in conduit for protection from damage purposes in short runs . The same as you can put nm in conduit to go down a basement wall to an outlet. That's why they sell a Romex to EMT adapter . I also wanted to know how to figure the conduit fill . I also thought some one would have installed a panel in a basement with living space above and would know what kind of conduit they used .
 
jetlag said:
I also wanted to know how to figure the conduit fill . I also thought some one would have installed a panel in a basement with living space above and would know what kind of conduit they used .
Click to expand...

Chapter 9 Note 9.

As for the fire rating, uh, er, uh... Punt!
 
You need a UL detail. Google search "UL F-C-3017". This detail is for NM cables through 2 hour rated gypsum. Follow the instructions closely and read every line to ensure this fits your specific installation.


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Thanks George

Thanks George

George Stolz said:
Chapter 9 Note 9.

As for the fire rating, uh, er, uh... Punt!
Click to expand...

Great job George, I knew I had seen that in the code before. Wow I won't be allowed to put very many nms in a 2" conduit that way counting the width as a diameter , I will need at least three 2 " conduits to get all the house wiring in . Plus 1 for the 4/0 ser cable . I've used the PVC for that before without getting flagged but this is my own house and I wanted everything as perfect as possible . I believe I saw in the IRC where things penetrating the ceiling must have the same or more hr rating. Maybe I can find the rating for PVC .
 
Thanks Npstewart

Thanks Npstewart

Npstewart said:
You need a UL detail. Google search "UL F-C-3017". This detail is for NM cables through 2 hour rated gypsum. Follow the instructions closely and read every line to ensure this fits your specific installation.


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Click to expand...

I will check on that today .
 
I can't find the article but, you can use a PVC conduit from the panel up to accept your cables but it cannot penetrate the ceiling and must be exposed.
 
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FWIW, the 5/8" layer of gypsum on the ceiling; underneath the
habitable areas above, is not considered a true fire rated assembly.
The layer of 5/8" gypsum is the only component meant to "slow
down" [ if you will ], ...a fire event in the garage below.

That said, any penetrations thru the ceiling should be sealed
completely with an approved type sealing material [ i.e. - fire
rated caulk, ...fire rated foam, ...mineral wool, etc. ]

Have you contacted the local AHJ for their input and approval
on your proposed installation ?............Also, ...are there any
Residential codes that are adopted in your location ?

= ( * ) =
 
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jetlag said:
I believe I saw in the IRC where things penetrating the ceiling must have the same or more hr rating. Maybe I can find the rating for PVC .
Click to expand...

Anything penetrating any type of fire barrier or partition MUST be protected or repaired with a UL listed assembly which most of the time consists of fire caulking around the outside air within the void space.

PVC Through Gypsum would have to be similar to this:

http://multimedia.3m.com/mws/mediaw..._1O8t1evUqe17zHvTSevTSeSSSSSS--&fn=FC2002.pdf
 
Regarding the detail in the posted link: Read the description for item 2. That detail is good for 3 cables at most in one hole. I think you could have multiple such penetrations as long as they were a few inches apart, but you can't take all of the cables from the panel through one large hole. With some search I think you will be able to find a detail that will work for several cables through a sleeve, or use multiple holes and this detail.

Edit: I mis-read the detail. It is good for up to 7 cables, but not larger than #12 conductors.
 
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jetlag said:
I plan to install a surface mounted panel box on a residential garage interior masonry wall . There are dwelling rooms above the ceiling so the ceiling in the garage must have 5/8" type x drywall . My question is can I use sch 40 rigid PVC to provide a sleeve up to through the ceiling to bundle the NM cables ? Also how do you figure the 40 % fill for the NM cables ? Do you just measure them and estimate the cross section areas ? I don't see any tables for conduit fill for cables with 3 conductors . Will I have to use Rigid Metallic or EMT because of the fire rating ?
Click to expand...

This would be a violation of 312.5, specifically exception (b).

It would be compliant if the PVC didn't penetrate the ceiling. Also derating applies if the PVC is longer than 24".
 
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Why not just build a chase where the panel is going with a couple 2X4's and a piece of 5/8" sheetrock. No conduit, no derating and your don't have to worry about penetrating the ceiling since the wires will be behind the 5/8" rock.
 
PVC Through Fire Rated Ceiling

North Star hit this topic right on the head, this 5/8" Type X sheetrock is only meant to slow the spread of a fire, it is not a rated assembly; as long as this a single or two family and that sheetrock does not separate the two dwelling units.
 
You cannot run the home runs in conduit. That is bundling. Fan the wires out against the wall and run up thru the ceiling. Have a metal cover built to cover the wires. Common install in Florida with attached garages and two story houses.
 
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In addition to penetrating any of the 5/8" gypsum board, ...be sure
to check for any derating factors that may be applicable when
you drill thru any framing members, and have NM type cable
assemblies passing through them [ RE: Section E3605.4.4,
in the `06 IRC ].


You may want to closer at what you're penetrating and with what,
before you actually decide to do it.

$ - - - - $
 
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