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Code Question: Running Wires through Holes and Stapling...

Code Question: Running Wires through Holes and Stapling...

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  #1  
Old 09-26-05, 08:32 AM
Mason156
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Code Question: Running Wires through Holes and Stapling...

I am wiring an addition that contains a laundry room and a kitchen with quite a few independent feeds. I am running the feeds through a crawlspace. I have a line of 1 3/8" diameter holes aligned in the joists (16" on center) that I have used to run the cables down the length of the addition. By the time I get to the end of the addition that's near the panel, there are five 12/2 NM cables in the holes. So my first question is is it a code violation to have 5 cables bundled in a hole like that? (I should say that 5 cables in a 1 3/8" dia hole only loosely fills the hole - there was never any resistance pulling the cable)

My second question involves what happens at the end of the addition when I want to be going parallel to the joist. My question is - do I have to split out and staple each wire in the bundle (or maybe a stack of 2) or is there some way that I can use a strap support to support the bundle of 5 every 3 feet or so?

Thank You in advance,

Steve
 
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  #2  
Old 09-26-05, 08:39 AM
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Join Date: Sep 2000
Location: United States
Posts: 18,497
You would have been better off, both structurally and electrically with two sets of smaller holes than one set of large holes.

The issue is ampacity derating. It's not related to how tightly or loosely the cables fit in the holes. With five cables, you'll need #10 for a 20-amp breaker and #12 for a 15-amp breaker. This is probably not what you wanted to hear.

There's still time to drill another set of holes parallel to the first and move two of the five cables over to that set. This will eliminate the problem.

There are multiple ways of handling running wires parallel to the joist. You can staple them individually, or in pairs. Or you can use plastic devices designed to hold multiple cables.
 
  #3  
Old 09-26-05, 08:44 AM
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Join Date: Feb 2002
Location: port chester n y
Posts: 2,117
The solution for securing N-M cables that are run parallel and along wood framing members is to use "Stack-It's"

A "Stack-It" is a plastic block with a fastening nail attached. You smash the nail into the wood member, and then insert the cables into slots on the block which fastens the cables in-place.A Very neat, effective,and time-saving method.You also avoid spreading the cables across the width of the joist/stud.

Good Luck & Enjoy & Learn from the Experience!!!!!!!!
 
  #4  
Old 09-26-05, 09:01 AM
Mason156
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Awesome - thank you for the time and misery you've both already saved me.

On the issue of derating the cable, am I reading your message correctly that I can run 3 20A circuits in my holes with 12/2 wire and make additional smaller holes for the remaining circuits?

Steve
 
  #5  
Old 09-26-05, 09:08 AM
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Join Date: Sep 2000
Location: United States
Posts: 18,497
You may put up to four 12/2 cables in the same set of holes without worrying about derating. It's that fifth cable that does you in.
 
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