jar546
Forum Coordinator
What IRC code would you cite?
(easy one)
(easy one)
-
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Derate NM Cable through top plates of garage
- Thread starter jar546
- Start date
Fortner
Bronze Member
Re: Derate NM Cable through top plates of garage
IRC 3605.4.4 or NEC 334.80
IRC 3605.4.4 or NEC 334.80
jar546
Forum Coordinator
Re: Derate NM Cable through top plates of garage
What are these guys thinking. Just make swiss cheese and pull 2 per hole.
What are these guys thinking. Just make swiss cheese and pull 2 per hole.
Fortner
Bronze Member
Re: Derate NM Cable through top plates of garage
That is what I usually see. Destroyed plates.jar546 said:
Re: Derate NM Cable through top plates of garage
jar546 ---
I don't want to pick on you but ...
The holes are not that bad. I would like to see them further apart, but it does not seem to be a big issue.
There is no need to derate the cables. More than 24" seems to be the "conduit" length that requires derating.
jar546 ---
I don't want to pick on you but ...
The holes are not that bad. I would like to see them further apart, but it does not seem to be a big issue.
There is no need to derate the cables. More than 24" seems to be the "conduit" length that requires derating.
raider1
Silver Member
Re: Derate NM Cable through top plates of garage
Under the 2005 NEC there was a loop hole that permitted you to not adjust the ampacity if the cables were not bundled for more than 10% or 10 feet. (See 310.15(A)(2) Exception). In the 2008 NEC 334.80 was change to state that the exception to 310.15(A)(2) would not apply to cables bundled through a firestopped framing member.
Chris
In the 2008 NEC you are required to adjust the ampacity of NM cables in accordance with 310.15(B)(2)(a). (See 334.80)GHRoberts said:
Under the 2005 NEC there was a loop hole that permitted you to not adjust the ampacity if the cables were not bundled for more than 10% or 10 feet. (See 310.15(A)(2) Exception). In the 2008 NEC 334.80 was change to state that the exception to 310.15(A)(2) would not apply to cables bundled through a firestopped framing member.
Chris
mtlogcabin
SAWHORSE
Re: Derate NM Cable through top plates of garage
N1102.4.1 Building thermal envelope.
The building thermal envelope shall be durably sealed to limit infiltration. The sealing methods between dissimilar materials shall allow for differential expansion and contraction. The following shall be caulked, gasketed, weatherstripped or otherwise sealed with an air barrier material, suitable film or solid material.
1. All joints, seams and penetrations.
10. Other sources of infiltration.
Don't do electrical so where's the foam in the top plate penetrations
N1102.4.1 Building thermal envelope.
The building thermal envelope shall be durably sealed to limit infiltration. The sealing methods between dissimilar materials shall allow for differential expansion and contraction. The following shall be caulked, gasketed, weatherstripped or otherwise sealed with an air barrier material, suitable film or solid material.
1. All joints, seams and penetrations.
10. Other sources of infiltration.
TimNY
Platinum Member
Re: Derate NM Cable through top plates of garage
Where is this located in the house?
If this were in an exterior wall of a garage that is not going to be finished, there is no concealed space, therefore no need for fireblocking.
If no fireblocking, then they are not penetrating a firestopped assembly?
I only have 2005 NEC, so I am not aware of all the verbage in the 2008, but this would seem to nullify 335.80 that raider1 quoted.
Where is this located in the house?
If this were in an exterior wall of a garage that is not going to be finished, there is no concealed space, therefore no need for fireblocking.
If no fireblocking, then they are not penetrating a firestopped assembly?
I only have 2005 NEC, so I am not aware of all the verbage in the 2008, but this would seem to nullify 335.80 that raider1 quoted.
Re: Derate NM Cable through top plates of garage
There is no fire stopping shown. The cables are not bundled. The breaker sizes are not specified. The usual derating from 90 degrees (wire rating) to 60 degrees (NM rating) is sufficient.
jarXXX seems to apply code requirements without enough context to make informed decisions. Perhaps jarXXX could explain how much derating the circuits need -
I don't do a lot of electrical work, but my understanding is:raider1 said:
There is no fire stopping shown. The cables are not bundled. The breaker sizes are not specified. The usual derating from 90 degrees (wire rating) to 60 degrees (NM rating) is sufficient.
jarXXX seems to apply code requirements without enough context to make informed decisions. Perhaps jarXXX could explain how much derating the circuits need -
raider1
Silver Member
Re: Derate NM Cable through top plates of garage
So IMHO the picture shows cables that run through the same opening and the building code do require that the holes in the top plate be draft stopped so adjustment of the allowable ampacity needs to be done.
Chris
Let me post the wording of 334.80.
This section say "through the same opening in wood framing that is to be fire or draft stopped using thermal insulation, caulk, or sealing foam."
So IMHO the picture shows cables that run through the same opening and the building code do require that the holes in the top plate be draft stopped so adjustment of the allowable ampacity needs to be done.
Chris
TimNY
Platinum Member
Re: Derate NM Cable through top plates of garage
I agree, if it is required to be firestopped.raider1 said:
raider1
Silver Member
Re: Derate NM Cable through top plates of garage
I would say the the top plate in the picture would need to be fireblocked in accordance with 2006 IRC section R602.8 #4.
And 2009 IRC section R302.11 #4
I agree, if it is required to be firestopped.TimNY said:
I would say the the top plate in the picture would need to be fireblocked in accordance with 2006 IRC section R602.8 #4.
And 2009 IRC section R302.11 #4
Chris
jar546
Forum Coordinator
Re: Derate NM Cable through top plates of garage
It is a garage wall that will be sheetrocked as there is a bonus room above. You are looking at the inside of the exterior garage wall that will be behind the bonus room kneewalls.
George, trying to figure out the jarxxx thing. Why the x's? Easier to type? :?
It is a garage wall that will be sheetrocked as there is a bonus room above. You are looking at the inside of the exterior garage wall that will be behind the bonus room kneewalls.
George, trying to figure out the jarxxx thing. Why the x's? Easier to type? :?
TimNY
Platinum Member
Re: Derate NM Cable through top plates of garage
It being a concealed location per jar's explanation, I think we're in agreement that it violated the NEC. Get out ye old recipro saw, notch it, staple em and put a 16ga strap across the top plate.
However, I disagree that 602.8 #4 (2006) or 302.11 #4 (2009) applies if it is not a concealed space. You can't get to #4 until you've met the requirements of the section first-- namely, "In combustible construction, fireblocking shall be provided to cut off all concealed draft openings"
My interpretation would be that since it is not concealed [in my theoretical scenario, not in this particular photo], you don't get to read any further and apply the subsections. In my opinion, it would be like going to the shaft enclosure section and picking something out of there when you don't have a shaft enclosure to begin with.
It being a concealed location per jar's explanation, I think we're in agreement that it violated the NEC. Get out ye old recipro saw, notch it, staple em and put a 16ga strap across the top plate.
However, I disagree that 602.8 #4 (2006) or 302.11 #4 (2009) applies if it is not a concealed space. You can't get to #4 until you've met the requirements of the section first-- namely, "In combustible construction, fireblocking shall be provided to cut off all concealed draft openings"
My interpretation would be that since it is not concealed [in my theoretical scenario, not in this particular photo], you don't get to read any further and apply the subsections. In my opinion, it would be like going to the shaft enclosure section and picking something out of there when you don't have a shaft enclosure to begin with.
Re: Derate NM Cable through top plates of garage
I see nothing wrong here. These cables are already derated for residential applications so much that there would have to be nine current carrying conductors before any further derating is required. Further, IF this will be a concealed location (looks like an exterior wall, and told in the garage) the typical insulaton to be applied suffices as draft stop.
I see nothing wrong here. These cables are already derated for residential applications so much that there would have to be nine current carrying conductors before any further derating is required. Further, IF this will be a concealed location (looks like an exterior wall, and told in the garage) the typical insulaton to be applied suffices as draft stop.
north star
Sawhorse
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Re: Derate NM Cable through top plates of garage
TimNY,
The drilled holes WILL be concealed once the sheetrock is installed, so R602.8, #4 would apply.
What's up with the lone "orange" conductor not installed in the drilled holes? :?:
TimNY,
The drilled holes WILL be concealed once the sheetrock is installed, so R602.8, #4 would apply.
jar,
What's up with the lone "orange" conductor not installed in the drilled holes? :?:
Re: Derate NM Cable through top plates of garage
I don't see a problem with the installation. They would need to seal the holes.
I would say the following section allows this type of installation. The conductors are only grouped together for 3" then they are seperated.
310.15 Ampacities for Conductors Rated 0–2000 Volts.
(B) Tables.
2) Adjustment Factors.
(a) More Than Three Current-Carrying Conductors in a Raceway or Cable. Where the number of current-carrying conductors in a raceway or cable exceeds three, or where single conductors or multiconductor cables are installed without maintaining spacing for a continuous length longer than 600 mm (24 in.) and are not installed in raceways, the allowable ampacity of each conductor shall be reduced as shown in Table 310.15(B)(2)(a). Each current-carrying conductor of a paralleled set of conductors shall be counted as a current-carrying conductor.
You sure there's a room above? Looks like rafters going up beside the joist to me.
I don't see a problem with the installation. They would need to seal the holes.
I would say the following section allows this type of installation. The conductors are only grouped together for 3" then they are seperated.
310.15 Ampacities for Conductors Rated 0–2000 Volts.
(B) Tables.
2) Adjustment Factors.
(a) More Than Three Current-Carrying Conductors in a Raceway or Cable. Where the number of current-carrying conductors in a raceway or cable exceeds three, or where single conductors or multiconductor cables are installed without maintaining spacing for a continuous length longer than 600 mm (24 in.) and are not installed in raceways, the allowable ampacity of each conductor shall be reduced as shown in Table 310.15(B)(2)(a). Each current-carrying conductor of a paralleled set of conductors shall be counted as a current-carrying conductor.
You sure there's a room above? Looks like rafters going up beside the joist to me.
north star
Sawhorse
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Re: Derate NM Cable through top plates of garage
Mule,
Jeff said that this was the openings in the wall that will be located behind the ' pony wall ' above.
How's your recuperation going?
Mule,
Jeff said that this was the openings in the wall that will be located behind the ' pony wall ' above.
How's your recuperation going?
TimNY
Platinum Member
Re: Derate NM Cable through top plates of garage
Yes, see below.
Tim
[/size][/b]north star said:
Yes, see below.
I agree with you.. The point was that I believe there are differing opinions as to whether or not you have to firestop the hole if it is not concealed. We were not originally privy to the location of the penetrations, and the location made a difference to some, and not to others.TimNY said:
Chris and I got a bit off topic, apologies. I tried to be clear.TimNY said:
Tim
north star
Sawhorse
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Re: Derate NM Cable through top plates of garage
TimNY,
No apologies are necessary!
In my own sort of "over-the-top" kind of way, I was attempting to be clear.
I hope that I helped in the discussion of this topic.
Mule, I agree, ...them thar " Golden Years ' ain't looking so golden to me
either. Wishing you the very best in your recuping time. Now, get back
out there and kick some code butt! :lol:
TimNY,
No apologies are necessary!
In my own sort of "over-the-top" kind of way, I was attempting to be clear.
I hope that I helped in the discussion of this topic.
Mule, I agree, ...them thar " Golden Years ' ain't looking so golden to me
either. Wishing you the very best in your recuping time. Now, get back
out there and kick some code butt! :lol:
Re: Derate NM Cable through top plates of garage
Looks like plenty of space to me. They are not jammed through the typical barely big enough hole. If they stuck a less than 24" chase in, they would be fine but the heat dissipation would be worse. This is the concern. Draft stop the holes appropriately and move on I say.
Looks like plenty of space to me. They are not jammed through the typical barely big enough hole. If they stuck a less than 24" chase in, they would be fine but the heat dissipation would be worse. This is the concern. Draft stop the holes appropriately and move on I say.