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ligito
06-23-2009, 10:12 PM
I hung some black pipe and then some conduit.
No wires in the conduit, yet.
I screwed a piece of 1 x 1 1/2 into the wall studs with 3 in screws, for pipe and conduit clamps to mount on.
I reached up with another piece of conduit, it touched the black iron pipe and the conduit and arced and flashed real good-I didn't have gloves on but felt nothing (good sign, I think).
I looked around and the best I could figure was one of the long screws just happened to pierce a wire for another circuit.
I used my voltage probe but found nothing that would indicate with my Fluke tester.
I pulled the suspect screw back out and it was very warm but no visible scorch marks, or arced spots. Must have just missed a nailplate.
I left the screw out and better use a longer board.

A.K. Boomer
06-23-2009, 10:48 PM
Could it be coming from one of the other screws? All will get warm after removal due to friction esp. with a drill driver.

ligito
06-24-2009, 02:25 AM
I'll turn the breaker off and try the others.
I would have thought something would light up with my tester.

Jim Shaper
06-24-2009, 02:41 AM
You got a flash, but it didn't trip the breaker? That doesn't sound right.

Don't feel so bad. I've been installing a storage platform in the yet to be covered rafters in my garage (the steel paneling should be here thurs). Working from a ladder to install the cross braces, I managed to shoot framing nails right through the romex lighting wires. Not once, but twice in the same stud. :o Of course I was on the other side of the truss beam, so I couldn't see that I was lined up right on the romex. I should've checked.

I knew the wires were there - I installed them a couple years ago. Nothing shorted, but that section of insulation is mangled. Mine's all coming out with the new ceiling going in anyways, but you should check yours.

ligito
06-24-2009, 12:53 PM
It did trip the breaker.
Glad it didn't trip me.
I only had one screw in close proximity to electrical.
I guess I should cut a hole in the drywall and see if I have to make repairs.

Dawai
06-24-2009, 01:49 PM
In the beginning we had bx cable.. It hung down from the knob and tube telegraph wiring system everyone used. Naked strands of wire stretched through the attic to attach receptacles to via armored cable.

The bx cable being armored with metal twist like flex? it resisted chewing by rats and drywall installations.. being then (when I started in the trade) a lot of lathe board, chicken wire and plaster. That didn't last but a year or two and sheetrock was going up everywhere. I hate them houses when I have to work on them.. you can't open a box up without cracking plaster in the next room.

I bet you find a nicked romex.. saw it before.. quite a few times before. When you nick the entrance cable in front of the breaker panel, no good shut off available.. it is a bad day sitting there listening to the frying sound in the wall. Just ask anyone who has installed cable television for a while..

ligito
06-24-2009, 06:15 PM
I started backtracking and found one of the screws that attached a conduit clamp to a joist had just caught the edge of the hot Romex conductor, where the wire passed through the hole in the joist.

I cut the wire, added 2 junctions boxes and a length of wire and now I'm back ( a couple of hours later --I don't work very fast, trying to stay alive). I also inserted a shorter screw in a different location, to hold the conduit clamp.