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Lost power to a few rooms upstairs on Sunday (ran a space heater and hair dryer at some time). I thought we tripped a breaker but nothing was flipped in the electric panel. I reset every breaker to be sure. Then I checked we were getting power to each one with a fuse tester and that looks good. I reset all the GFCIs and found one that wouldn't reset out by the garage. So I replaced it and it reset but it didn't solve the problem.

  • What do you mean by "fuse tester"? Do you have fuses or breakers? Did you completely flip the breaker to OFF before flipping it back to ON? Many breakers will trip to an intermediate state, requiring them to be explicitly turned OFF before being turned back ON. When you replaced the GFCI and reset it, did it actually turn back on, or did it trip immediately? – mmathis Jan 11 '17 at 15:27
  • Thanks for the reply. I meant to say voltage detector, not fuse tester. I flipped every breaker to completely off, then back on, including the main breaker and sub-panel. As far as I can tell, they don't have an intermediate state. I also checked the house for any other GFCI outlets, but couldn't locate any. When I replaced the GFCI and reset it, it came back on and stayed on (still on now), but the power upstairs in a few rooms is still out. – user64988 Jan 11 '17 at 15:33
  • Sounds like you may have somehow melted a wire or receptacle (or wire nut) through without causing a short, which would have tripped a breaker, so you now have an open circuit somewhere. Impressive. – topshot Jan 11 '17 at 17:36
  • You should be able to see a pattern in the receptacles that are out. Is it possible for a GFCI receptacle to be able to supply power to its own receptacle but not to the load terminals? – Jim Stewart Jan 11 '17 at 17:56
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It just means that a wire termination (where a wire meets a receptacle, wire nut or switch) failed somewhere from the overload. It failed in an arc-fault mode, meaning it burned out like a fuse then arced across the gap, until the arc self-extinguished. If it had not, you'd be seeing your insurance man in the morning.

The connection didn't short against another wire, so it didn't make a short circuit. That's why it didn't trip the breaker. Breakers are not "Magic Master Detect-All's". They make those; they're called dual-mode AFCI/GFCI breakers. The AFCI would have tripped from the arcing, stopping the arc in case it did not self-extinguish.

So now you need to go hunt down the bad connection, starting at the panel. Electrical circuits are wired like a tree, they can have any number of branches, but they never loop back to themselves. Most are wired linear like a vine. The problem is either at the last functioning outlet or the first bad outlet. The top candidates are:

  • Backstab connections
  • Aluminum wire on old non-aluminum-rated terminations (basically all terminations out there on Al wire)
  • Loose amateur-done wirenuts - wirenuts are one of the few times "gorilla tight" is appropriate
  • Screws not tightened enough
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Non contact testers will give false positives when the dead wire run is parallel to a live run. Verify with a plug in lamp or other device and find the last working outlet On the circuit. Check that and the first non working outlet for a bad connection. If the back stabs on the outlets are used that can be the point of failure on either the black/ hot or white/ neutral wire.

  • Thanks, Ed. So if I find that the backstabs are used, then what is my next step? Replace the outlet? Or would the wires themselves need to be replaced? – user64988 Jan 11 '17 at 19:55
  • If the wires are not damaged you can re use them. Most back stabs have a space that a solid #14 copper wire can be pressed in to release the ones you want. If the wires have pits from bad connections I cut them off at the damage and re-strip. I use back & side terminal outlets not quite as fast as stabs and they do cost a few dollars but they are worth it. With damaged wire I like to pig tail all the hots connected with a wire nut then a short piece to the outlet. same with the neutral and the ground should already be this way. My personal opinion is that stabs for outlets should be outlawed – Ed Beal Jan 11 '17 at 20:04
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It would be good for me to know how old the house/wiring is..... Off-hand, if wire-connections are all good in the Panel, it is possible that a connection burned/arced-through at the fault location. Note this could be just as easily on the White/Neutral side as the Black/Hot wire. This means that the original connection could have been flaky/NOT secure, and the overload caused the [flaky] connection to fail. This means it could have been arcing for some time, and that being the case you should find discolored wiring at the bad joint/device - either wire-nut, or back-of-the-duplex outlet (for example) connection supplying the loads.

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