Anyone ever get failed for to many wires in a drilled hole?

[mcclary's electrical]

First, I only do special inspections anymore when I have the time as I was promoted up the chain and second we require all the holes to maintain the fireblocking in one and two family dwellings, not firestopping. We deal with firestopping in commercial applications and we do have some local requirements that govern this application as well. We do not look at the fill for the hole being drilled.....we do look for damage to the cable for trying to cram more cables in a hole thus damaging the cable's jacket....but thats about the department has time to concern themselves with at this point.

Secondly, I have never failed anyone whom follows the, state adopted building codes, NEC? and/or local requirements set forth by city council, the mayor and the city charter.

Have a nice day !

FYI- Here is a nice article on it : http://www.fomo.com/building-technologies/from-the-experts/fireblock-vs-firestop.aspx

Thanks Paul, and the only reason I wrote that is last year I did a duplex on w. cary. You "personally" came in and told me about the NM cables in a hole to be firestopped. Actually, this was your ONLY recommendation to me on that day, so I assumed it was important to you. Thanks, again Paul. See you later.

 

[electricmanscott]

. We do not look at the fill for the hole being drilled.....we do look for damage to the cable for trying to cram more cables in a hole thus damaging the cable's jacket....but thats about the department has time to concern themselves with at this point.

Suppose the jacket sustained some damage during installation. What happens then?

 

[danickstr]

i guess I would tape it.

 

[mcclary's electrical]

another linkhttp://gfretwell.com/electrical/NEMA%20Romex%20in%20foam%20study.pdf

 

[danickstr]

the interesting thing about NM-B as a fill percentage, is that we are really talking about 20% of the actual fatness of the sausage casing being a CCC (or even less). This seems to be a built-in moderator in heat issues. I know that NM-B as "fill" is a bit contradictory, since it is designed to be its own conduit of sorts, but with fire/draft fill being an issue, I guess it could actually use its own percentage, based on actual cross section. How about it, NEC 2011?

 

[jeffhornsby]

You derate with the 90C but after derating it has to be equal or greater than the 60C.
Is there any other insulations where you size per 60C and derate at 90C. I know if lowest terminal rating is 60C, but I mean like in 334.80 where the code requires

 

[Brian Pic]

wires in holes drilled

wires in holes drilled

It is my understanding with wires in holes is as follows:

Use 310.16
*14 AWG rated 20 amp
*= visit 240.4(D)
240.4(D) unless specifically permitted in 240.4(E) or (G), the protection shall not exceed that required by (D)(1) through (D)(7) AFTER ANY CORRECTION FACTORS FOR AMBIENT TEMPERATURE AND NUMBER OF CONDUCTORS HAVE BEEN APPLIED.
Then go to 310.15(B)(2)(a)

3-14/2 NM cables would be 6 current carrying conductors.

14 AWG=20amperes(310.16) x .80(310.15(b)(2)(a) = 16 amperes

3-14/2 per hole
2-14/3 per hole
so on so forth

 

[Barclaymyers]

If you look at a firestop listing card it will often refer to the amount of "cable fill" you are allowed to have. there is typically one of 2 types of fill noted (sometimes both)

The types are...

Actual Fill: this is the mathematically calculated amount of fill you have; cross sectional area of all the cables express as a percentage of the opening's area. The listing may say something like "40% actual fill allowed"

Visual Fill: this is the "what does it look like" amount and most listings using this type will allowing for "100% visual fill".

The choice of type is dependent on the manufacturer and the testing agency.

Interestingly enough most holes that are 100% visual fill usually come between 40% and 60% actual fill, those teeny spaces can really add up.

It's actually really simple: Follow the firestop listing card and you can;t get it wrong.

 

[rgiraldo]

Same over here. No more then two, sometimes three. And if you read the hilti FireStop manuel or any other fire stop manual it will tell you the amount of the product and inch require to fill the hole. UL

 

[rgiraldo]

Hey thats funny, the guy above me wrote what I wanted to say with detail. I just wrote what ever. Never mind going to BED.. good night :roll:

 

[augie47]

Once the hole is fire or draft stopped the 24" rule goes out the window. Inspectors who just make up a number like no more than 2 or 3 cables in a hole have no idea what they're doing. I could put 4-3 wire cables through a hole and still only have 8 CCC's.

Rob, In one way, I'm not excusing inspectors who "pull numbers", but you have to "play to your audience". If I am dealing with Code savvy electricians I will discuss the "derating" and let them calculated the number of current carrying conductors. Sometimes, when dealing with "trunk slammers" and homeowners, brevity becomes a key to the instructions and one simply says "no more than 3 romex", etc. I appreciate that sometimes thats how misinformation is spread, but KISS is sometimes a necessary tool.

 

[infinity]

Rob, In one way, I'm not excusing inspectors who "pull numbers", but you have to "play to your audience". If I am dealing with Code savvy electricians I will discuss the "derating" and let them calculated the number of current carrying conductors. Sometimes, when dealing with "trunk slammers" and homeowners, brevity becomes a key to the instructions and one simply says "no more than 3 romex", etc. I appreciate that sometimes thats how misinformation is spread, but KISS is sometimes a necessary tool.

Augie, I feel your pain, but this is no different than applying other aspects of the code during an inspection. An inspector should be inspecting according to the code not because it's easier for him to say not more than 3-2 wire cables in a hole because he's too lazy to do the calculation where there may be 4 cables within a hole. This is no different than counting the number of CCC's in a raceway or applying the hundred of other variables written in the NEC. But I do understand your point.

If an EI said that putting only three cables in a hole would keep you from doing a calculation so you can use it as a rule of thumb I could accept that, but saying the code only allows you three cables is just wrong.

 

[Pierre C Belarge]

Rob, In one way, I'm not excusing inspectors who "pull numbers", but you have to "play to your audience". If I am dealing with Code savvy electricians I will discuss the "derating" and let them calculated the number of current carrying conductors. Sometimes, when dealing with "trunk slammers" and homeowners, brevity becomes a key to the instructions and one simply says "no more than 3 romex", etc. I appreciate that sometimes thats how misinformation is spread, but KISS is sometimes a necessary tool.

I agree with this. The only thing I might add, I would present the code section to the trunk slammer and let him figure it out. It is not the inspectors job to do a calculation and provide the installer with it, it is the installer's responsibility to provide the calculation and let the inspector check those calculations.

 

[augie47]

Simply to verify (and not as an excuse), I do the calculation and do not enforce simply by number of cables. The "lazy" part comes from not wishing to explain it to someone who cares less about the Code or "why", but simply wants to know what to do to pass.
One of the disappointing aspects of this job in some of the areas I work is the number or folks who don't wish to attend free seminars but depend on your inspections to teach them Code. More than one have said "tel me how you want it done so I can pass and don't try to explain it to me"..
they need a "concrete" number, the same folks want you to say "always drive two ground rods", etc.
You don't see them on the Forum :grin:

 

[C3PO]

Simply to verify (and not as an excuse), I do the calculation and do not enforce simply by number of cables. The "lazy" part comes from not wishing to explain it to someone who cares less about the Code or "why", but simply wants to know what to do to pass.
One of the disappointing aspects of this job in some of the areas I work is the number or folks who don't wish to attend free seminars but depend on your inspections to teach them Code. More than one have said "tel me how you want it done so I can pass and don't try to explain it to me"..
they need a "concrete" number, the same folks want you to say "always drive two ground rods", etc.
You don't see them on the Forum :grin:

I know exactly what you mean. It sure seems that our area is full of these type of people.

 

[satcom]

I know exactly what you mean. It sure seems that our area is full of these type of people.

Great point on some that feel the inspector is there to teach them, when our state went to required CEU to renew a license, it brought a lot of these lazy guys up to speed.

 

[infinity]

Great point on some that feel the inspector is there to teach them, when our state went to required CEU to renew a license, it brought a lot of these lazy guys up to speed.

You mean the guys who hadn't opened a code book in 20 years and then waste the instructors time with some of the dumbest questions you've even heard. Sorry if I'm somewhat cranky but there are times, in a CEU class, that I want to scream at some of these guys.

 

[fondini]

Heck,
Paul Abernathy will fail you at the drop of a hat. :grin:

I think the real question is: who is Paul Abernathy?

 

[mcclary's electrical]

I agree with this. The only thing I might add, I would present the code section to the trunk slammer and let him figure it out. It is not the inspectors job to do a calculation and provide the installer with it, it is the installer's responsibility to provide the calculation and let the inspector check those calculations.

I agree 100%,,,,,in fact,, beside every box 2gang and up, I write my calculations on the stud , right above the box for the inspector to see.

 

[hurk27]

I think the real question is: who is Paul Abernathy?

go to page 4, and read the signature of post #40:roll: