Supporting wire with new run


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Old 06-20-06, 12:05 PM
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Question Supporting wire with new run

I tried to find some info on this, but this was the closest I could find:
http://forum.doityourself.com/showth...upporting+wire

When you run NM wire, how often do you need to support it? By support, I mean, affix it to something solid. If you ran wire across the rafters to the center of the ceiling, the wire could hang for say 6 or 7 feet without any support.

Here are two examples:

- Wire running across rafters, near the end/crease that are 24" OC.

- Wire coming down through the top plate to an outlet, with a vertical drop of 8'.

The wire would have to be located in the center of the stud, so that its at least 1 1/4" from the outside nailing edge. Please correct me if I'm wrong on this.

Thanks,
Dr. A>
 

Last edited by DrAnonymous; 06-20-06 at 12:23 PM.
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Old 06-20-06, 01:57 PM
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NM cable must be secured and supported by an approved means every 4 1/2 feet. Approved means include staples, stack-its, etc. The only time you are allowed to exceed the 4 1/2 foot requirement (that I am aware of) is in a residential application, above a suspended ceiling, when droping to a light fixture - which may be 6 feet.

If you ran wire across the rafters to the center of the ceiling, the wire could hang for say 6 or 7 feet without any support.
This would not be legal. If I understand you, your saying running the cable in the same direction as the rafter. In this case you would need to staple the wire to the side of the rafter every 4.5 ft, being sure to stay atleast 1.5 inches from the nailing edge.

- Wire running across rafters, near the end/crease that are 24" OC.
This is legal, but some inspectors will still require you to staple the wires every 4 1/2 ft. And it is important to stay in the crease area, you may not run wires over the surface of rafters in the "middle" of your attic space. (there is a bunch of math for figuring out how far from the crease is legal, but I can't recall it off the top of my head ... if you stay as far in the crease as you can reach you should be good. And you must stay atleast 6 feet away from any scuttle holes (access holes to the attic)

- Wire coming down through the top plate to an outlet, with a vertical drop of 8'.
In this case, the cable should be stapled (or otherwise secured) to a vertical stud every 4.5 ft, and within 8 inches of the box. And yes stay atleast 1.5 inches from the nailing surface of the stud, so basiclly right in the very center of a 2x4.

Good Luck
-Matt
 
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Old 06-20-06, 03:06 PM
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Outstanding! Thanks so much for the input. I've seen some of the special fat staples before, but not the gun. Are they expensive and where might I get one?

If you drop a line down a stud and then go across 6 studs to another outlet box, do you need to do anything special on the horizontal wire? I assume you drill the holes centered and thats it.

Thanks,
Dr. A>
 
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Old 06-20-06, 03:19 PM
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Wires that go across a wall through the studs do not need any additional stapling between the studs. The same goes for wires that go across a ceiling through the joists.
 
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Old 06-20-06, 11:23 PM
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Quick and easy..... The code states....

"NEAT AND WORKMAN LIKE"
So basicaly, support it, make it look nice (even though no one will ever see it again). Protect it from damge and use COMMON SENSE (uncommon), and you should be fine. Don't make tight 90% angles, let the wires flow.. but not too loose.
additionaly, staples are cheap!!!!!!!

Just remember they (staples) are not holding the building together, they should be "snug" on the wires not buried to the hilt.
 
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Old 06-21-06, 05:17 AM
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I've seen some of the special fat staples before, but not the gun. Are they expensive and where might I get one?
I've never used the staple guns for romex, I personally prefer a simple insulated staple, that you bang in with a hammer. And, as lectriclee said, you don't want to "bury" the staple ... If you've deformed the wire by driving the staple way in, you've gone too far, and probably damaged the insulation on the conductors. Snug is where it's at.

-Matt
 
 

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