Romex Routing in Attic

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  #1  
Old 02-18-07, 06:50 AM
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Romex Routing in Attic

I'll be wiring my workshop under the guidance of the electrical sub that's doing our new house. I've done several smaller wiring projects over the years. But, to keep me from unnecessarily bugging him for advice, I have a couple of questions so far.

When routing the romex in the attic, (Wood framing), what's the best way? Is it normal practice to just run it directly across from junction box to junction box or should the wiring be secured along the joists and then across to the next junction box? Should I drill 3/4" holes in the joists instead of laying the wiring on top?

It seems that running it directly to the boxes would save on excess wiring, but running it along the joists and then across to the boxes would be neater.

Thanks!

Larry
 
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Old 02-18-07, 07:27 AM
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Do you have joists or truses? Trusses should not be drilled.

Wiring within 6 foot of the scuttle will need to be protected by running boards. Regardless, the wiring needs to be secured within 8" of the box, and than no more than 4 1/2' after that.
 
  #3  
Old 02-18-07, 07:35 AM
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Yes, they are trusses. So, I guess I should run the romex over the tops of truss bottoms. It seems that securing the romex to the sides of the trusses, every 4' feet, then running it over each truss to get to each box would work. I would do this only in places that will not see any any traffic in the storage areas I have planned. Sounds like a plan?

I've never heard of the term "scuttle".

Thanks for your help!

Larry
 
  #4  
Old 02-18-07, 09:28 AM
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Romex Routing in Attic

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Last edited by 69-er; 02-18-07 at 12:50 PM. Reason: duplicate post
  #5  
Old 02-18-07, 10:17 AM
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Do not drill any holes in any trusses.

The rules for cable routing in an attic depend on several factors. One important factor is whether the attic access has a permanent ladder or stairs. The second main factor is whether the cable will run within six feet of the access opening.

If there is no permanent ladder or stairs, and the cables will be more than six feet from the access hole, then you can just lay the cables on top of the framing. Staple the cable to the framing near each box.
 
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Old 02-18-07, 10:33 AM
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When running the cable parallel to the framing members, you should staple the cable to the sides of the framing. When running the cable perpendicular to the framing members, and resting on top of them, no staples are needed (except near each box).

"Scuttle" is the name of that hole you climb through to get into the attic.
 
  #7  
Old 02-18-07, 12:49 PM
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Fold-Up Ladder?

Thanks, John!

Are the fold-up type ladders considered permanent? That's what I plan on using so I can easily use a small portion around the scuttle for storage. I can easily keep all wiring 6 feet away from the opening.

Larry
 
  #8  
Old 02-18-07, 07:04 PM
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running along the top of joists is fine,
just make sure if you're within 7ft of the scuttle hole you're supporting your cable either on the inside of the joist, along a running board, or to the roof rafters (NOT ON THE TOP OF THE JOISTS)

(I believe the 6ft rule changed to 7)
 
  #9  
Old 02-19-07, 06:59 AM
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When running across the top of the trusses you can try to keep your wiring tucked close to the inside corners of the web (where the open angle is smallest). There it will be the hardest for anyone to ever step on if they are in the attic for maintenence because they will be unable to squeeze their foot into this protected area.
 
  #10  
Old 02-19-07, 07:30 AM
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No, the 6-foot rule is still 6. The 7-foot value in this section of the code refers to the height above the floor of the attic.

Yes, a set of folding stairs would be considered permanent. If you install such stairs, you would need "substantial guard strips" on all cables running perpendicular to the framing (everywhere on the attic floor and within 7 feet upwards from it, not just within 6 feet of the acesss hole). A "substantial guard strip" is generally interpreted as a 2x4.

If you follow jn's advice to keep the cables near the inside corners, make sure that the cable is not vulnerable to being cut by the metal braces that hold the truss members together.
 
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