Romex in fire caulked holes

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sweetcav

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Central Pa
We recently got busted for running 5 nm cables through 1 1/2" holes that were fire caulked we were told that they need to be derated and now we are only allowed 2 nm cables through a fire caulked hole. This doesn't sound right to me but i want to know how to do the calculations myself so i can see and where in the 08 code is it.


Thanks for any help, I have been reading this for a long time and have learned quite a bit from it.
 
Welcome to the Forum

It's semi-correct :)
In '08 an added ppg to 334.80 states that when two or more NM cables are run thru caulked holes NM must be derated.
As it works out, when using the 90? insulation rating and 310.15(B)(2)(a) it does not effect your end ampacity until you reach the 10th current carry conductor or (5) 12/2 cables.
 
Anyway - the derating is the same 310.15 tables they always were... Derating the capacity of the conductors happens at 3 or more CCC's, but has little dramatic affect until 10-20 CCC's. And this would apply if they were stacked or bundled >24", but now the code actually stipulates the 'holes' if insulated or stuffed with goop.... No goop - no problem...

If they were all fixed lighting loads one could argue the connected load if below the derated capacity would not increase.

FYI there is simular wording in the '05 at 334.80
 
So I can run 4 12/2 or 14/2 through the hole and even after derating them i would still be ok. my calculation would be 30 x.7 =21 amps and 25x.7=17.5amps right
 
sweetcav said:
So I can run 4 12/2 or 14/2 through the hole and even after derating them i would still be ok. my calculation would be 30 x.7 =21 amps and 25x.7=17.5amps right
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You could run 4-12/3 or 4-14/3 cables and still be under the 10 CCC's that takes you to 50% derating. You calc's look good. Whoever said that you're limited to two cables doesn't understand the derating requirement.
 
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I am confused now. Where I am located, I have been told that I am to have no more than 6 cc conductors through a fire stopped hole. In fact I was told 2 was the better number because testing showed that the fire caulked point could exceed the temperature rating of the insulation. I have not seen the testing, but that is what the inspector told me.

The logic of the 6 ccc's is that even after derating, you have to chose the ampacity of the weakest link in the system...the breakers. They are rated at 60/75 degrees...therefore, you have to work from the 75 degree column. Thus, after 6 ccc's you have a problem derating wise.

This is what I have learned/been taught and keeps me passing inspections, and this logic is from two seperate AHJ's.

c2500
 
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c2500 said:
I am confused now. Where I am located, I have been told that I am to have no more than 6 cc conductors through a fire stopped hole. In fact I was told 2 was the better number because testing showed that the fire caulked point could exceed the temperature rating of the insulation. I have not seen the testing, but that is what the inspector told me.

The logic of the 6 ccc's is that even after derating, you have to chose the ampacity of the weakest link in the system...the breakers. They are rated at 60/75 degrees...therefore, you have to work from the 75 degree column. Thus, after 6 ccc's you have a problem derating wise.

This is what I have learned/been taught and keeps me passing inspections, and this logic is from two seperate AHJ's.

c2500
Click to expand...


What does the breaker temp have to do with this hole ? This is just pure crazy trying to run up cost for a problem that is not there. Red tag money is all they want.
 
c2500 said:
I am confused now. Where I am located, I have been told that I am to have no more than 6 cc conductors through a fire stopped hole. In fact I was told 2 was the better number because testing showed that the fire caulked point could exceed the temperature rating of the insulation. I have not seen the testing, but that is what the inspector told me.

The logic of the 6 ccc's is that even after derating, you have to chose the ampacity of the weakest link in the system...the breakers. They are rated at 60/75 degrees...therefore, you have to work from the 75 degree column. Thus, after 6 ccc's you have a problem derating wise.

This is what I have learned/been taught and keeps me passing inspections, and this logic is from two seperate AHJ's.

c2500
Click to expand...

So a breaker rated at 75C with 90C wire derated for 8 CCC still leaves 21 amps for a #12 and 17.5 amps for #14. As long as the final OCPD is not greater than the weakest link (75C rated breaker) then there is no issue.

The idea is to use the 90C for derating purposes because the wire is capable of a higher ampacity then the breaker would allow.

So keep the OCPD at 20 amps for #12 and 8 CCC's and your good. For #14 wire- the 15 amp breaker works up to 8 CCC also.
 
Jim W in Tampa said:
Sometimes the inspector keeping his job depends on red tags to fund his employment.
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That is what it seems to be coming to. My crowd can not manage the money so they want to cut jobs beginning with Code Enforcement. Like all mandated services it is not self supporting. Police,Fire,etc are not self supporting but we sure as hell don't want to do without them.
 
You know, this is one part of the code I have always had issues with..because of what is said here...and the way things are enforced. Truthfully, it is not a big deal to have to drill an extra hole or two. Also if testing shows that the temperature can truely be excessive than so be it. I do what I am told, and I pass. I respect the inspectors I interact with and can say they are not going off half cocked because there is consistentcy between two different AHJ's. Perhaps their continuing education is teaching it?

I do have to wonder though, as to why there is such broad interpretation of this section? For the inspectors here, I would love to hear your thoughts. FYI 2006 IRC/2005 NEC...residentially speaking.

Thanks,

c2500
 
c2500 said:
I do have to wonder though, as to why there is such broad interpretation of this section? For the inspectors here, I would love to hear your thoughts. FYI 2006 IRC/2005 NEC...residentially speaking.

Thanks,

c2500
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I don't see where there is any room in this code section for a broad interpretation. The wording is very clear and straightforward. The cables must be derated. The rules for derating are in Article 310. Seems clear to me, unless I'm missing something.
 
Rob,

I am not questioning the derating. I was commenting on where I am I have to derate NM in the 75 degree column because that is the weakest link temperature wise in the system

c2500
 
c2500 said:
Rob,

I am not questioning the derating. I was commenting on where I am I have to derate NM in the 75 degree column because that is the weakest link temperature wise in the system

c2500
Click to expand...

Again this goes back to someone incorrectly applying the code. Derating is based on the conductor temperature value not the termination. This is very clearly written in 110.14(C).

If a #12 conductor had a hypothetical ampacity of 50 amps at an insulation value of 200? C you would use the 50 amps to start your derating. Even if after derating the conductor had a value of 40 amps then you would use the terminal value to determine the final ampacity of the circuit.

Starting your derating, when you have a 90? C conductor, from the 75? C column because the terminal is rated for 75? C is incorrect.
 
rob where is the specific language located that allows us to use the 90 degree
table when derating. I know I have found it somewhere but I wish the code makers would put it where its obvious.
 
also found code section 334.80 which says that we may use the 90 deg table for derating and the section 334.12 that says that nm must have conductors rated at 90 deg under the construction type. So a bit of research and my questions are answered.
 
They got me also

They got me also

I was turned down today because the inspector told the HO I could not have more than 2 nm's through a fire caulked hole:mad:. I had my guns loaded with 334.80 but being Friday afternoon the inspector was no where to be found and had turned his cell phone off.
Also on this job the HO wanted to save some money and ask if he could run his own conduit for his garage/shop area and then I would install the wireing. I gave him the pointers for strapping and having every thing secure. He installed EMT on the ground and around the wall that will be covered with 4" of concrete. The first thing that caught my attention when I saw it was the set screw couplings. I told him they had to be changed because of the concrete. He then showed me the box where it stated they were listed for direct bury and concrete encasement. OK. Save that box. Other than that every thing was good. The inspector was going to gig the couplings also until he showed him the box with the listing. Then said he would have to research the use of EMT under concrete because " he had not seen EMT under concrete in 20 years". So I will load 358.10 B for my phone call Monday morning.
 
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