Drywall for Fire Rating

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Little Bill

Little Bill

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It is customary in new residential construction to just stub out the NM through a hole in the ceiling drywall for a fluorescent light.
What if the primary purpose of the drywall is to provide a 15 minute fire barrier in a garage with living space above, would the hole for the NM need to be fire caulked?
 
Probably yes. I would. Ask the fire inspector or the building inspector.

One time I did 8" opening in a fire rated residential garage and the AHJ along with the fire inspector showed me how to patch that section so it retains the fire rating. In that case it was more than a hole on the ceiling.
 
Little Bill said:
It is customary in new residential construction to just stub out the NM through a hole in the ceiling drywall for a fluorescent light.
What if the primary purpose of the drywall is to provide a 15 minute fire barrier in a garage with living space above, would the hole for the NM need to be fire caulked?
Click to expand...
People do it every day but the romex is not really suppose to connect inside the florescent fixture . You can hit a surface box with the romex and then use flex with 105 c wire to enter the light . Yes the hole around the wire has to be fire chaulked . You can use the blue or red . I have 6 wires stubbed out in my car port that will go into the florescent when the dry wall goes up , the inspector here is not that ticky about the 105 c or maybe he doesnt know .
 
Little Bill said:
It is customary in new residential construction to just stub out the NM through a hole in the ceiling drywall for a fluorescent light.
What if the primary purpose of the drywall is to provide a 15 minute fire barrier in a garage with living space above, would the hole for the NM need to be fire caulked?
Click to expand...

If the ceiling is double 1/2", 5/8", or double 5/8", it's for a fire rating. The yellow 2hr firestop is fine for patching that cable that pokes thru. A tube is ~$10 and will be needed elsewhere in rough-in for stopping vertical penetrations in bottom/top plates. I would firestop a garage penetration w/o a second thought, even if bldg code didnt require it.
 
jetlag said:
People do it every day but the romex is not really suppose to connect inside the florescent fixture . You can hit a surface box with the romex and then use flex with 105 c wire to enter the light . Yes the hole around the wire has to be fire chaulked . You can use the blue or red . I have 6 wires stubbed out in my car port that will go into the florescent when the dry wall goes up , the inspector here is not that ticky about the 105 c or maybe he doesnt know .
Click to expand...
I might get corrected , that might be 90 c wire required instead of 105 c , either way the romex is only rated 75 c because of the sheath covering even though the conductors are 90 C .
 
jetlag said:
People do it every day but the romex is not really suppose to connect inside the florescent fixture . You can hit a surface box with the romex and then use flex with 105 c wire to enter the light . Yes the hole around the wire has to be fire chaulked . You can use the blue or red . I have 6 wires stubbed out in my car port that will go into the florescent when the dry wall goes up , the inspector here is not that ticky about the 105 c or maybe he doesnt know .
Click to expand...

Are you saying that just the light itself requires 105C wire regardless of the firewall or because it's in a firewall?
 
That is so 2,000's. This is 2017. LED strips are taking over and they need a backbox usually because the inside is not available and there is usually 6'' of conductors sticking out the back someplace (not always at the center, it is a guessing game if you get no specs.)

I don't just stick a cable out for fixtures any longer, fire rated or not. They all get a box.
 
jetlag said:
People do it every day but the romex is not really suppose to connect inside the florescent fixture . You can hit a surface box with the romex and then use flex with 105 c wire to enter the light . Yes the hole around the wire has to be fire chaulked . You can use the blue or red . I have 6 wires stubbed out in my car port that will go into the florescent when the dry wall goes up , the inspector here is not that ticky about the 105 c or maybe he doesnt know .
Click to expand...

NM cable contains 90° C conductors and is permitted to enter directly into a fluorescent fixture. The 60° C rating has to do with it's ampacity. If you use a box behind the fluorescent fixture that is surface mounted then the conductors within that box must be accessible without removing the fixture.
 
infinity said:
NM cable contains 90° C conductors and is permitted to enter directly into a fluorescent fixture. The 60° C rating has to do with it's ampacity. If you use a box behind the fluorescent fixture that is surface mounted then the conductors within that box must be accessible without removing the fixture.
Click to expand...

This does not apply to all fixtures. I have installed fluorescent fixtures that prohibit the connection to be made in the fixture.
 
edward said:
This does not apply to all fixtures. I have installed fluorescent fixtures that prohibit the connection to be made in the fixture.
Click to expand...

Yes I agree, but that's is due to the design of the fixture and listing compliance not a direct NEC prohibition. Same would apply if the fixture required 105 C degree conductors.
 
Little Bill said:
Are you saying that just the light itself requires 105C wire regardless of the firewall or because it's in a firewall?
Click to expand...

No the conductors entering has to do with the fixture specs so most commercial will leave the flex with the 90c or 105c so not have to worry what fixture is used . That has nothing to do with the fire rated ceiling , you just need to fire rate the opening around the penetration in the dry wall . If it is going to be inspected I would leave it stubbed and fire chalked , when you get the rough in inspection ask the inspector if he wants a surface box mounted and a flex to the fixture . You might get by with a direct connect inside the fixture .
 
macmikeman said:
That is so 2,000's. This is 2017. LED strips are taking over and they need a backbox usually because the inside is not available and there is usually 6'' of conductors sticking out the back someplace (not always at the center, it is a guessing game if you get no specs.)

I don't just stick a cable out for fixtures any longer, fire rated or not. They all get a box.
Click to expand...

No matter what date it is , he said fluorescent not led . The leds are not required by code "yet" . You still have to figure the total house load on a service by old school no matter how many led light you "say" you are going to use .
 
+ = + = +


Small openings in the Garage ceiling can also be sealed with
regular old gypsum mud.......The Garage ceilings typically are
not true "fire rated" assemblies, but rather a single layer of
gyp. board applied to the Garage side......This single layer
of gyp. board does serve as a fire barrier, and all penetrations
\ openings must be sealed......The tube of "fire rated" caulking
does not have to be used.

The intent is to "not" provide an opening in the gyp. board for
the fire to find another source of oxygen and to spread.

The amount of moisture in the gyp. board is what provides the
time limit \ fire rating.


= + = + =
 
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