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Any electricians out there?(5 posts)

Any electricians out there?mr_spin
Jan 29, 2002 2:35 PM
I want to insulate my attic, but the house was built in 1931, and has old knob and tube wiring. NEC is very specific about not allowing insulation anywhere near knob and tube, although you can get exemptions where I live if the wiring is in good shape.

I was planning on rewiring the house anyway, so I won't be keeping the knob and tube. I will be doing the work myself, having done a fair amount of wiring in my time. I won't be joining the union anytime soon, but I have plenty of inspector approved experience.

I've done a fair amount of research, but can't find an affirmative answer on this question: How do I run NM cable across an attic? Do I need to use amoured cable, or can I simply staple it to the joists? Or should I build a raceway above the joists and staple the cable to it? Or can I run NM against the insulation?
Not an electrician, but I've done itscottfree
Jan 29, 2002 4:45 PM
Don't know where you live, and what your specific code requirements are. Or even if you're going to have it inspected -- is this a homeowner project that doesn't require inspection?

At any rate, when I built my house several years ago, I simply laid Romex cables (I assume that's what you'll be using) across the attic joists, didn't even staple them. Unrolled insulation right over top. Passed inspection no problem, inspector didn't even question it.

There's a weird code requirement that you can't use Romex above a third story, but I doubt you'll have that problem.

The answer to your question is: It's safe, it'll work fine, no stapling if you don't want to bother, and at least in rural Kentucky it'll pass inspection.
re: Any electricians out there?Birddog
Jan 29, 2002 7:19 PM
Just run type NMB (romex) across the rafters or ceiling joist. They should be stapled though, and all junction boxes should have a cover. One of my pet peeves is finding open junction boxes. They are usually full of crap and a potential hazard. Insulation can be laid right over Romex in most any jurisdiction. Having grounded plugs will be a nice bonus after this project is complete.
Jan 30, 2002 10:57 AM
That makes it easy. I hear you about the junction boxes. Last time I did a wiring project I ran into all kinds of rat nests in the boxes. I take a lot more pride in my work.

Having grounds will be nice, but I still need to go under the house to get most of the outlets. In the attic, mostly I'll be dealing with fixtures. I love going under the house...not!
A couple more thingsBirddog
Jan 31, 2002 6:35 AM
After you re-wire, remove all traces of the old stuff where it is exposed so the next owner/remodeler won't be confused.
As you probably already know, having and assistant when you go under the house is nearly mandatory. You can speed up the process, by having the romex precut and stubbed down, so all you have to do is shove the wire back up the next hole. Also, it is well worth removing all the old metal boxes if you can, and replacing them with modern plastic ones called "old work" or "remodeling" boxes. It is much easier to pull the wires and also to make up the joints and install the device. I assume you are also installing a modern panel as well (if it hasn't been upgraded in awhile).

Godd luck,