"Clean" Romex installs...

Maybe a silly question, but for the sake of good practice and appearance, when running wire is there a preference when it comes to pulling 2-3 cables through a single hole in a stud or joint OR drilling a separate evenly spaced hole for each cable? For clarification, I mean common residential receptacle and lighting circuits.

I run up to 3 cables thru a hole (#12 or #14)
Less holes in joist etc the better

Typically, up to four NM cables in a hole will NOT cause or bring up any issues.

2x4's I usually drill 7/8" holes dead center. Bigger framing gets 1" or 1-1/8" holes.

We always put multiple cables in a single hole. As many as will comfortably fit.

For 2008 NEC, Article 334.80 for Ampacity of NM cable states.

Where more than two NM cables containing two or more current-carrying conductors installed, without maintaining spacing between the cables, through the same opening in wood framing that is to be fire- or draft- stopped using thermal insulation, caulk, or sealing foam, the allowable ampacity of each conductor shall be adjusted in accordance with Table 310.15(B)(2)(a) and the provisions of 310.15(A)(2) shall not apply.
Where more than two NM cables containing two or more current-carrying conductorsare installed in contact with thermal insulation without spacingbetween cables, the allowable ampacity of each conductor shall be adjusted in accordance with Table 310.15(B)(2)(a).

Table 310.15(B)(2)(a) Adjustment Factors for More Than
Three Current-Carrying Conductors in a Raceway or Cable

Number of ---------------- Percent of Values in Tables
Current-Carrying ------------- 310.16 through 310.19
Conductors ---------------- Adjusted for Ambient
--------------------------- Temperature if Necessary
_________________________________________________
4 - 6 ______________________80
7 - 9 ______________________70
10 -20______________________50
21 -30______________________45
31 -40 _____________________40
41 and above__________________35
_________________________________________________

Being that you can use the 90 degree column for derating purpoes its not usually a problem with #14,#12,and #10 conductors untill you pass 9 current carrying conductors.
That would make 4 cables = to 8 current carrying conductors since the exception doesnt apply.
or you could have one of the cables be a three wire then 4 would equal 9 current carrying conductors and would be ok.

Sorry havent figured out how to get the Tables to look right.

codeone said:

Being that you can use the 90 degree column for derating purpoes its not usually a problem with #14,#12,and #10 conductors untill you pass 9 current carrying conductors.
That would make 4 cables = to 8 current carrying conductors since the exception doesnt apply.
or you could have one of the cables be a three wire then 4 would equal 9 current carrying conductors and would be ok.

Click to expand...

Just a quick note.

Don't for get that the neutral of a MWBC (multi-wire branch circuit) does not count towards derating, so for home runs or branch circuit wires you can even have four 3-wire cables. In fact, only two of the conductors in a 3-way switching setup will ever carry current so IMO they apply as well, although it is not written that way.

Speedy Petey said:

Just a quick note.

Don't for get that the neutral of a MWBC (multi-wire branch circuit) does not count towards derating, so for home runs or branch circuit wires you can even have four 3-wire cables. In fact, only two of the conductors in a 3-way switching setup will ever carry current so IMO they apply as well, although it is not written that way.

Click to expand...

Thanks for pointing that out Speedy Petey.
Mel