Running wires through floor trusses


Old 12-29-05, 05:36 AM
Thread Starter
Join Date: Nov 2005
Posts: 43
Received 0 Votes on 0 Posts
Running wires through floor trusses

I'm roughing in the electrical at my new house and the house has wood floor trusses that I've run many wires through. The trusses are "open" meaning you can see through them. Do I need to secure the wires running through them? None of them are sagging. Thanks

Sponsored Links
Old 12-29-05, 01:00 PM
Join Date: Oct 2005
Location: Milwaukee WI
Posts: 1,338
Received 0 Votes on 0 Posts
I am assuming you are using NM. The question is whether you have to staple the wires, right?

300-4(a)(1) requires 'bored holes' to be at least 1-1/4" from the nearest edge. I know you don't have bored holes, but are your wires 1-1/4" from the nearest edge of the framing member? This is for protection from nails.

336-18 says that 'cables run through holes in wood or metal joists, rafters, or studs shall be considered to be supported and secured.' Note it does not say 'bored holes' so if they consider a truss to be a joist, you would be OK.

You should check with your local authority. Or maybe someone else has a better reference. I only found two references to 'truss' in the 1999 NEC, and neither has anything to do with what you're talking about.
Old 12-29-05, 03:13 PM
Join Date: Sep 2000
Location: United States
Posts: 18,497
Received 0 Votes on 0 Posts
Cables running perpendicular to the trusses, and supported by virtue of the fact that they are sitting on the trusses, need not be stapled. But you can if you want to.

If these trusses are in the attic, then the issue of protection comes into play. Post back if you're talking about an attic.
Old 12-29-05, 09:00 PM
Thread Starter
Join Date: Nov 2005
Posts: 43
Received 0 Votes on 0 Posts
Thanks. They are running in the basement and 1st floor to second floor. For the second floor to attic I have put down running boards.

The trusses are built with what looks like regular 2x4's so they should be thick enough. I just wanted to make sure I didn't have to strap them down.
Old 12-29-05, 09:59 PM
Join Date: Nov 2004
Location: USA
Posts: 973
Received 0 Votes on 0 Posts
You may still want to ask the AHJ (inspector). If I recall correctly, when my brother-in-law built their house a few years back (east Tennessee) the inspector required him to staple them. Could be a local rule, could be that the inspector was wrong, or could be that I've slept since then and am remembering wrong.

Even if you don't have to staple them, I would still try to make some effort to keep them well away from those metal plates (what ARE they called?) that hold the 2x4's together. I imagine those can easily strip into the Romex sheathing.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: