I'm pulling 14-2, 14-3, and 12-2 perpendicular to I-joists. Cannot see any guidelines or NEC rules governing the number of cables that can be run through a typical 1" or 1.5" hole through the web. How many cables can I stuff through the holes before the bundle is too packed and the AHJ makes me derate? TIA. Chuck
I think there is a rule about such short runs not requiring derating.
Bob is right, you don't derate until the conductors have been bundled or enclosed in a raceway for 24". The real question is whether you might damage the cables installing them where they don't fit..
Does that apply to conduit also ? I am referring to a sleeve going threw a cinder block wall with data cabling, can I stuff it to 100 % if its under 24''
If it is a conduit you are required to follow the "fill" rules, no matter how short it is but there is no specific language for "fill" in a bored hole. I have heard of inspectors using conduit fill rules on holes but that is not in the code. The generally accepted rule on holes is they should not be stuffed to the point that they can damage the jacket when you are pulling them. YMMV as to what that means to an inspector. You also start bumping up on the 1.25" rule if the hole gets too big. Cables must be at least 1.25" from the edge of the stud in both directions or you need a 1/16" kick plate to protect them. That only allows an inch of space to drill holes in a 2x4.
Derating really means that you have to reduce the ampacity of conductors in a single pipe or bundle if there are more than 3 carrying current. The size of the conduit is not mentioned. 4 current carrying #14s will get derated in a 4" conduit to 80% of the 310.16 ampacity. You will use the appropriate insulation rating column so this is not really a factor on 14 and 12 ga THHN until you get over 9 conductors since you are limited to 15 and 20a respectively by 240.4(D)
I'm taking real easy on the cables while installing them. I called the inspector and he said there is no limit on the number of nm cables running through bored holes as long as they are not tightly bound (tie-wrapped) between the holes. They just want to see the sheath isn't damaged and the cable is allowed some breathing room between joists.
Read the exception.
"V. Communications Wires and Cables Within Buildings
800.48 Raceways for Communications Wires and Cables. Where communications wire and cables are installed in a raceway, the raceway shall be either of a type permitted in Chapter 3 and installed in accordance with Chapter 3 or a listed nonmetallic raceway complying with 800.51(J), (K), or (L), as applicable, and installed in accordance with 362.24 through 362.56, where the requirements applicable to electrical nonmetallic tubing apply.Exception: Conduit fill restrictions shall not apply."
Maybe so but when he added the Romex it falls back under 60% fill rule.
Read the exception.
"V. Communications Wires and Cables Within Buildings
800.48 Raceways for Communications Wires and Cables. Where communications wire and cables are installed in a raceway, the raceway shall be either of a type permitted in Chapter 3 and installed in accordance with Chapter 3 or a listed nonmetallic raceway complying with 800.51(J), (K), or (L), as applicable, and installed in accordance with 362.24 through 362.56, where the requirements applicable to electrical nonmetallic tubing apply.Exception: Conduit fill restrictions shall not apply."
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