I replaced the garbage disposal at my in-laws' place that has been leaking for years. It's an old house, and nothing in the panel is labeled. So I flipped what I assumed to be the right breaker and went to test the outlet. I put the probes on both bottom nuts and it popped and I lost power to G/D and dishwasher.

So I went ahead and replaced the disposal with new wire running to the switch and a new switch. I flipped the breaker back -- no power. I pulled the dishwasher out and there's a junction box that feeds both the dishwasher and G/D. No power there either, the wire then runs in the ground which I assume goes to the breaker.

I have power at the breaker. I have both a non contact tester and a light up with the probes. I striped the wire coming from the breaker to junction box back and exposed the wires, and turned on the breaker. And my non-contact tester will detect power, but my 120V light isn't going off.

Is it really as simple as "I burnt something in the wires and need to replace the run going from breaker to junction box"? Or am I completely missing something?

No GFIs are in-line that I can tell... everything is hardwired.

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  • Do you have power at the switch? – StainlessSteelRat May 21 at 1:43
  • im assuming when you say switch you mean on the appliance side and the answer is no. i took that one step further and followed the wire to a junction box (no power) where it splits off to dishwasher and then to im assuming the breaker.so in my head the only thing now in line is Breaker then wire. i have power at the breaker, go to the end of my wire no power. – divedeep May 21 at 2:08
  • i apologize about the terms and what not running purely on common sense here. not an electrician by any means – divedeep May 21 at 2:09
  • You say new switch in your question. As SamR says, odds are that it not the wiring. Unless there is a pony panel or junction box between breaker box and appliances, I have no idea. Did the breaker trip when you shorted out the circuit? – StainlessSteelRat May 21 at 2:47
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    Oh! Then I stand corrected. If that's black/white/bare then it's not an MWBC (unless it's horribly miswired). – Harper - Reinstate Monica May 21 at 16:13

You smoked your neutral

Now with your pictures, I see this is not a multi-wire branch circuit, just a simple circuit.

The white needs to go to neutral, and from your pictures and comments, we can see it does not. I would bring it to a different screw if it will reach; this one may be charred. Still, loosen up that screw and get the bit of wire out of it.

I suspect it "burned out" at this location, right where the wire meets the screw. Perhaps the screw was loose, and that caused arcing which damaged the wire over time; or your short was enough to cause the burnout. I suspect a little of both.

The black needs to go to 1 circuit breaker, and the breaker needs to be an appropriate size for the cable. The cable will be marked either "14 AWG" which needs a 15A breaker, or "12 AWG" which needs a 20A. If the breaker size was wrong, that would contribute a lot to the wire burnout.

Neutral being dead explains why the non-contact tester senses voltage on the hot ... but the conductive tester doesn't sense any voltage. As you know, a voltmeter requires 2 connections and the neutral is dead.

  • Thank you very much!! Ill read up on that now. This makes sense. So my only option would be to run new wire from breaker to appliance? assuming theres only one wire running to the jbox where it splits off to dishwasher and garbage disposal i was assuming both appliances were on the same breaker, i know thats not code,but lot is not code in the panel) is it possible to run one wire to two different breakers? – divedeep May 21 at 13:41
  • @divedeep get us some photos. For one, I'm not sure what you mean by "wire" - if you mean cable then maybe. It's probably not necessary to run new cable from panel to appliance, but it is necessary to know exactly what you have. – Harper - Reinstate Monica May 21 at 13:58
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    thanks Harper, ill take some good pictures and get back on here in an hour or so. – divedeep May 21 at 14:04
  • not the best pictures but thats whats there. It just seems way to simple to be this difficult. Im assuming the neutral at the panel(pictured) is the problem? you can see the exposed copper wire is just sitting against the bar while the white one runs thru the nut. again assuming the little discoloration i see on the exposed one is heat damage and it burned off at the nut where it was sharing the same neutral as a different breaker that was turned on still? – divedeep May 21 at 15:54
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    just to let you know. you are correct. traced it into the crawls space where i found a junction box that lead to some old wires leading to the breaker. Bad termenation of the black. breaker = old cable = junction box = 12-2 = junction box = dishwasher – divedeep May 21 at 22:39

Almost impossible to burn out house wiring, that is what the breaker prevents. Turn the breaker OFF then ON. The breaker should have tripped when you saw sparks. Your tester may have faulted also. Start with the breaker.

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    I flipped the breaker off then back on. My testers 120 light goes off at the breaker but not at the end of my wire. – divedeep May 21 at 1:20
  • Quite possible, and apparently demonstrated. – isherwood May 21 at 16:24
  • Thanks for the edit isherwood. You seem like a smart fella. Do you think the run of 12-2 coming from the breaker is shot and needs to be reran. I reconnected the loose wire in the panel still nothing. – divedeep May 21 at 17:15
  • NP. However, this isn't a discussion forum. If I had some insight to share beyond what Harper has said I'd post an answer. Please take the tour to see how it all works. – isherwood May 21 at 17:54

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