My neighbor called me over to look at a problem he is having with a string of dead receptacles. Long story short I can trace the wires in the attic to a penetration in a top plate with to romexes in it. I am assuming one in, one out like the rest of the daisy chain. Tic tracer says hot in, dead out. The problem is when I go down in the house I only find 2 receptacles(both dead), neither really under the penetration and they are both dead ends. I am guessing I have a buried J box in there somewhere but I would like any other suggestions before I start busting drywall. My plan is to put my big "underwater retriever" magnet on the top of the ceiling drywall right next to the penetration and finding it from downstairs with a chunk of metal, as a sanity check, then going in the wall there to see where it goes.
I just thought of another step. I may take that humongus magnet and see if I can find a buried box. The place is all steel boxes
If a really good tracer is not available, than you might be surprised at the ability of those Zircon stud finders with the AC finder on them. I've used one in a similar situation and narrowed down the source of the dead spot to within an inch.
You just put the selector on AC (some of the units have an automatic AC detect on every setting) and wave it side to side and downward, starting at the top of the wall where you know that it's hot. As soon as you loose the signal, that's the spot. I'd repeat the test a few times to be sure before I put any holes in the wall.
The only draw back I see with the magnet approach is that you could also be looking for a flying splice or a cable that has been nicked by a nail or other homeowner "modification", even years ago, that has finally burned through.
I like the idea of using the magnet to verify your location below .... there's nothing like opening the wall just one stud off!
Otherwise ... check your assumptions. I had a similar situation not long ago, where both cables turned out to be switch legs, with the feed coming in from the crawl space.
I know this sounds basic ... but nearly every time I've had a 'bad string of receptacles,' the problem has been at the last 'good' receptacle.
The few times the problem was elsewhere, the problem traced to an unconnected wire in a junction box / device box that got buried by the rockers. In this case, you can still find the box with a toner, as the tone will sound through the opening in the mud ring.
Another aid in finding a buried box is a 4 ft level ... to look for small bumps in the wall.
No crawl space, slab on grade and all electric comes down from the top. This thing was working 3 days ago and just quit. Everything in the house is back stabbed. I have been fixing that as I open boxes. Ground and neutral are bonded. There does seem to be some rough looking drywall in the area that I suspect and that will be by first place to excavate. I have been put on hold. They are going up north so this will be continued later. Thanks all for your suggestions