Multiple NM cables through common hole in studs

[mstrlucky74]

I took my drywall down and noticed there are multiple(2-3) romex cables running horizonal through the same holes in the wood stud. Is that allowed oer NEC? Thanks.

 

[Lectricbota]

I took my drywall down and noticed there are multiple(2-3) romex cables running horizonal through the same holes in the wood stud. Is that allowed oer NEC? Thanks.

When you have more than 9 current carrying conductors you need to start derating for NM.

334.80 is the code reference and the commentary following that in the Handbook is a handy reference.

 

[RICK NAPIER]

You only need to derate if the hole in the stud "is to be sealed with thermal insulation,caulk, or sealing foam"

 

[Dennis Alwon]

You only need to derate if the hole in the stud "is to be sealed with thermal insulation,caulk, or sealing foam"

Rick that is a matter of opinion. If the holes are drilled horizontally across a few studs over 2' then, IMO, these conductors are bundled. Obviously that is arguable.

 

[jap]

Rick that is a matter of opinion. If the holes are drilled horizontally across a few studs over 2' then, IMO, these conductors are bundled. Obviously that is arguable.

The rule indicates where bundled "Without maintaining Spacing".

Does it indicate anywhere how much "Spacing" there should between the cables before you could omit the
derating requirements?

 

[Lectricbota]

The rule indicates where bundled "Without maintaining Spacing".

Does it indicate anywhere how much "Spacing" there should between the cables before you could omit the
derating requirements?

You'd have an uphill battle trying to explain to our AHJ that you are maintaining spacing running horizontally through framing members using the same hole for multiple cables. JMO

I have been looking for anything in 2011 NEC to clarify-but still coming up empty.

 

[infinity]

I agree with Rick. The term "Without maintaining Spacing" is not defined and there is enough air around the cables to make them with spacing. We can argue this one all day. :roll:

 

[jap]

If you look at the # of romexes coming out of of the top of 42 cir panels nowadays in a 16" horizontal void,
if the panel is 24" or more down from the top plate you'd have to derate everything to start with.

 

[infinity]

If you look at the # of romexes coming out of of the top of 42 cir panels nowadays in a 16" horizontal void,
if the panel is 24" or more down from the top plate you'd have to derate everything to start with.

So in your opinion by virtue of the fact that they're close together they're considered bundled?

 

[jap]

So in your opinion by virtue of the fact that they're close together they're considered bundled?

If they are touching each other I'd say yes, since if they are touching there's no seperation.

 

[jap]

Otherwise I dont feel you could ever enforce the fact that several cables going through an 1 1/2" wide stud would be considered
bundled.

 

[iwire]

I agree with Rick. The term "Without maintaining Spacing" is not defined and there is enough air around the cables to make them with spacing. We can argue this one all day. :roll:

We could, yet it is up to the inspector to decide.

So in your opinion by virtue of the fact that they're close together they're considered bundled?

IMO yes is there is no spacing.

 

[kwired]

If they are touching each other I'd say yes, since if they are touching there's no seperation.

Usually, there is several small bundles leaving the panel with maintained spacing between them and not one big bundle. For whatever it is worth.

Otherwise I dont feel you could ever enforce the fact that several cables going through an 1 1/2" wide stud would be considered
bundled.

Do you not have the same thing if you had same number of cables with some kind of strap, clamp, etc. that effectively "bundles" them at similar intervals as the hole in the studs does? Now if you had some kind of mechanical spacer between cables to ensure that spacing is maintained - then you still would just have bundling for the thickness of studs - but only at each stud.

 

[jap]

Usually, there is several small bundles leaving the panel with maintained spacing between them and not one big bundle. For whatever it is worth.

Do you not have the same thing if you had same number of cables with some kind of strap, clamp, etc. that effectively "bundles" them at similar intervals as the hole in the studs does? Now if you had some kind of mechanical spacer between cables to ensure that spacing is maintained - then you still would just have bundling for the thickness of studs - but only at each stud.

Yes, you do. That's what I'm saying. If you consider several cables that pass through horizontal bored holes and touch each other for at least 24" as "Bundled" then you would have to consider the several cables that
come out of the top of a loadcenter as bundled also if they are all touching each other for 24" and between
2 studs from the top of the panel to the top plate, therefore requiring derating right from the git go regardless of what they do down the line.

There were some previous responses that indicated they thought since the cables were running through
horizontal bored holes it was safe to assume that the cables were still touching each other or "Bundled"
between the studs beyond the bored holes.

 

[RustyShackleford]

When you have more than 9 current carrying conductors you need to start derating for NM.

334.80 is the code reference and the commentary following that in the Handbook is a handy reference.

Not to nitpick, but you actually have to de-rate if there are more than 3 current-carrying conductors (that run "without spacing" for more than 24", or through a caulked hole), per Table 310.15(B)(3)(a). However, for practical purposes, it's correct that you're fine with up to 9 CCCs, since the 70% derating factor for 7-9 CCCs still allows the usual 15 and 20 amps with 14ga and 12ga NM, respectively.

 

[GoldDigger]

Y
There were some previous responses that indicated they thought since the cables were running through
horizontal bored holes it was safe to assume that the cables were still touching each other or "Bundled"
between the studs beyond the bored holes.

The experimental results done on firestopped wiring ( I can't find the URL at the moment, but it is in a different thread here) showed them deliberately spreading the NM apart inside the wall spaces between penetrations for their testing. This is something that an inspector would have to evaluate at rough-in when the wiring was visible.

 

[jap]

Not to nitpick, but you actually have to de-rate if there are more than 3 current-carrying conductors (that run "without spacing" for more than 24", or through a caulked hole), per Table 310.15(B)(3)(a). However, for practical purposes, it's correct that you're fine with up to 9 CCCs, since the 70% derating factor for 7-9 CCCs still allows the usual 15 and 20 amps with 14ga and 12ga NM, respectively.

To me this is a contradiction of terms.
what does the "Caulked Hole" have to do with it?
Are you saying that I can run 12 cables "Without Spacing" together for 23 15/16" inches without having to
derate, but I cant run the same 12 cables through a bored hole through an 1 1/2" wide stud if I caulk the
hole after they're installed?

 

[GoldDigger]

To me this is a contradiction of terms.
what does the "Caulked Hole" have to do with it?
Are you saying that I can run 12 cables "Without Spacing" together for 23 15/16" inches without having to
derate, but I cant run the same 12 cables through a bored hole through an 1 1/2" wide stud if I caulk the
hole after they're installed?

That is exactly what the code is saying. In the specific case that insulating caulk of the type used for fire blocking, as required by code for some situations, is used.
You can argue about the wisdom of the decision, but that is what 2011 NEC states.

 

[jap]

What is the Code Article is that in?

 

[GoldDigger]

What is the Code Article is that in?

334.80 (2011)