Pulling wire in the walls

[Eigenvector]

One question, when re-wiring an outlet, for instance to replace the old useless Romex with clipped grounds, with fresh new 12/2 - how do you tell where the wire goes? I mean how do you tell without hacking chunks out of the wall?

In my house it looks reasonable that the Romex goes from the attic and drops down to the outlets, so in this case it would be stapled to the studs going up - but what's the easiest way to determine that without major destruction of the wall? For all I know it could be threaded through the studs (or worse in front of the studs as was done in a few spots). I guess you could use a stud finder or the like, but old Romex is pretty heavily shielded and it'd be easy to lose the run among the studs.

If I'm looking at demolishing the wall, I might as well remove the entire wall in one sheet - at least then I can put up insulation while I'm there and clean out the buggies.

[JoeSpareBedroom]

Depressing news: In my previous house, built in the 1940s, the Romex was stapled every which way. Goodbye, walls, at least for the part I rewired. But, when we got estimates for redoing the kitchen, 3 electricians said they were comfortable snaking new wires in existing walls, even though it meant the wires couldn't be fastened to the studs. How they expected to do this, I have no idea.

[Mikepier]

If you are replacing your romex because it has no grounds, there are

2 ways to fix this without snaking new wires. You can put a GFI outlet on the first outlet of the circuit, which then protects anything downstream of the outlet, or you can protect the entire circuit with a GFCI breaker. In most jurisdictions, code permits this. You are protected against shocks.

[Eigenvector]

Well I guess that's an option. In that case I'd only have to do the outlets and the panel.

Both responses that I've heard so far, yours included, tell me that I'd either get used to GFCI outlets or break out the crowbar and start knocking holes. If it comes to knocking holes, I'm replacing the whole drywall sheet and putting up the insulation might as well kill 2 birds with one stone. I'll also probably halt my painting, no sense painting the walls if I have to rip it out anyway.

I so much want to do this the "right" way, and not fall back on GFCI outlets - but time and money talks.

[JoeSpareBedroom]

Sheetrock is cheap, and the insulation will pay for itself quickly. As you said, time's the issue. But, with home projects I've never done before, I find that once I figure out how to do things efficiently, the second room usually goes quicker than the first. Usually.

[Bob F]

If the wire comes from the attic, go up there and determine where it drops into the walls. If that cooresponds to the same stud space as the outlet, you can drill a new hole near the old one, and run a wire puller down to the box, and pull a new wire. Or, you can use a flex drill to drill from a box hole in the wall up into the attic or down into the basement. One way or another, it probably can be done without trashing walls. Things like insulation can make it more difficult.

Bob

[James "Cubby" Culbertson]

I've always wondered about fishing wires through existing walls. Code says the wire should be attached to the studs and near the boxes. Is there an exemption for remodel work? Just curious. Cheers, cc

[Larry and a Cat named Dub]

[hallerb]

in message

Well having been thru this myself:(

Had a outlet that the incoming wire was dead, never did figure out where it came from:( plaster walls no obvios signs a real mess.

I just ran new line, left old line in box capped of with tiny note capped off line appears dead, dont know what breaker its on. so you run a new line connect it to whatevers convenient of the same gauge

I had a box with a outlet hot neutral reverse wires too short box too small to pigtail:( Removed outlet left wires with wire nuts, installed blank cover.

Added new outlet a foot away feed from convenient nearby receptable in basement.

Obviously you cant attach wires to studs buried in walls its old work, make CERTAIN romex is attached firmly to box, I found a home once where ome jerk saved money didnt use any cable clamps:(

The short review is abandon the existing outlet, remove receptable, wire nut wires, perhaps note which breaker inside box for future owner. Install blank cover!

Install new outlet nearby, get book wiring simplified.

Buy electricians bit up to 6 feet longer longer with extensions drill down from attic or up from new hole cut in wall, run new romex. I leave a central attic workbox for additions, makes life easy when we really need outlet over here! Bit has hole in end to attach string to then pull wire:)

Its challenging but FUN to snake wires thru walls No DEMO needed!

[Doug Miller]

"Nonmetallic-sheathed cable shall be permitted to be unsupported where... the cable is fished between access points through concealed spaces in finished buildings or structures and supporting is impracticable." [2005 NEC, Article 334.30(B)(1)]

[Doug Miller]

Why do you *care* where the old cable goes?

Run the new cable however you can, or however you must, to get it to where you need to get it. Disconnect the old cable at both ends and abandon it in place.

[John McGaw]

The simple answer is to leave the old wire in place but disconnected at each end. And if you are being kind to someone who comes after you then both ends can be labeled neatly. Then you run new wire in the easiest way which is safe and code-compliant.

If you are dealing with an unfinished basement then coming up from there has always seemed the easiest way to manage outlets to me. An unfinished attic has always seemed easiest for ceiling fixtures.

[Toller]

My understanding is that is only for new construction, to prevent damage from the drywallers and carpenters. Obviously you can't staple new wires in existing wall, neither is there a need to.

I haven't checked this in the code, so you might want to do that before believing me...

[Doug Miller]

Hey, here's a radical idea: next time, check the Code first, *before* you answer the question.

[Eigenvector]

There are a few reasons why someone might care. One it's sloppy construction, but that's not a big deal to me. Two, I would like to recycle the old wire. Three, it would be nice to be able to use the old wire to pull the cable run for the new wire - which is why I care where it goes.

[Doug Miller]

There's nothing "sloppy" about leaving abandoned wires inside walls where they are not visible.

You haven't thought that one through very far.

Even at current copper prices, it's not worth the trouble. The copper in 12/2 NM W/G weighs about an ounce a foot -- IOW, the scrap price *after* you strip the jacket off the cable, and strip all the insulation off the conductors, is going to be *at*best* about eight to ten cents per foot of cable. Less if it's

14ga wire. Still less if it's older NM with de-rated grounds (14ga ground in a 12ga cable, 16ga ground in a 14ga cable).

In case you're thinking about recycling the cables without stripping the insulation first... I suggest you call a recycler, and find out how much they pay for cables in that condition. You'll be lucky to get much more than a penny a foot. Hardly worth the trouble of pulling the cables out, and definitely not worth the cost of the gas to drive to the scrap yard.

And that's assuming that you could even pull the old cables out of the staples inside the wall cavities anyway. You can't. Not unless you open up the walls, and pull the staples out of the studs. And if you do that, I promise that it's going to cost you a *lot* more to repair the walls than you're ever going to recover by recycling the copper.

Yeah, it would be nice if you could do that -- but you can't. See last objection to #2 above re: staples.

All of which is why you really *don't* care (or shouldn't care, anyway) where the old cables are.

[Don Young]

Fishing a new cable into an existing box is routine for old work electricians. There are a lot of ways to do it. If you have attic access you can try pulling the old cable out but it is pretty unlikely to work. A small sash chain dropped down and a long wire with a hook will work most times. You can get a little access around the box where the repair will be covered by the plate. The best thing is a friend who has experience as an old work electrician.

Don Young

[Eigenvector]

I got one of those (friend who's done lots of old work electrical). I watched him pull his old aluminum Romex at his place and replace it with copper - so it can't be useless or impossible to pull the old stuff like Miller is claiming. It wasn't easy though and he did need to punch a few holes in the wall. I guess I'll wait then, he doesn't fly back into the country until May'ish.

[Bob F]

"Eigenvector"

If you want to patch holes in the wall, great. I would choose to abandon the old wire if it is stapled in place.

Bob

[hallerb]

Yeah the old wire is basically valueless, after you go to all the removal work and strip all the insulation and patch the excess holes you will HAVE to make.

Far easier to bag groceries, and pay will be better