Running NM across roof trusses

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  #1  
Old 06-14-05, 08:53 AM
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Running NM across roof trusses

Is it permissable to run NM cable perpendicular to roof trusses (or parallel, for that matter)? I would staple them at each truss. Would I need to install them on a running board to protect them, or can I leave them as they are (exposed). This is in my attic (of course), so there would be no traffic, and I don't use the attic for storage.
 
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  #2  
Old 06-14-05, 09:06 AM
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Article 230.23:

If the attic has permanent stairs or ladder, it can be run without protection on the surface of the rafters only at 7' or higher above the floor or floor joists. If below 7', it must be protected by "substantial gaurd strips that are at least as high as the cable". Not sure what they mean by "substantial gaurd strips". I'm sure EMT or schedule 80 PVC would also be acceptable. If there are no permanent stairs or ladder, "protection shall only be required within 6' of the nearest edge of the scuttle hole or attic entrance."

Hope that helps.

Juice
 
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Old 06-14-05, 11:30 AM
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Sounds good. Thanks, Juice.
 
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Old 06-18-05, 09:22 AM
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Glad to help. Good luck.

Juice
 
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Old 06-20-05, 07:36 AM
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Follow up: What if I have a scuttle and want to add a stairway?

So, let's say I have a scuttle now and want to replace it with a permanent pull-down "dissapearing" stairway. Does this mean that I then need to go back and re-do any wiring up in the attic that is already done?

Clearly, any cable that could be "stepped on" should be protected... the question is do you have to protect all cables in the space whether or not they could be "stepped on"? For example, what about in the smallest portions of the attic near the gutters where the clearance is so small that a person couldn't get there?
 
  #6  
Old 06-20-05, 07:42 AM
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You raise an interesting point - NM cable run in a space so small that nobody could ever "step on" it seems as though it should be an exception. All I can really tell you about that is what the Code reads. I suppose it also takes into account that storage of "stuff" could be shoved that far back and damage the cable. Otherwise, any cable run below 7-feet still needs protection. There is a product called U-Gaurd, which is sort of like a conduit ripped down the center, forming a U shape. It can be installed over your cable without having to remove it and put it in a proper conduit. I am not an inspector, but it seems as though if you got some U-Gaurd, or alternately if you had a table saw and ripped some3/4" conduit down the center and installed either over the cable it would be adequate protection against physical damage to the cable.

I don't know if that helps you, but I hope so.

Juice
 
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