I was using a circular saw and thought that I blew the circuit breaker.

The breaker I have on the line is a GFI and I noticed that "test" button on the breaker was no longer working and I couldn't get light to go on even after resetting the breaker.

I purchased new breaker and replaced the old one. Now the "test" is working and I detect current at the circuit breaker between a black wire and the ground (the breaker box itself). At the wire that feeds the light (and the receptacle I connected the saw to) I still detect current between black wire and ground but not between the black and white wires. And light is not turning on.

Additionally when I use a non-contact current tester it beeps both at the white and the black wire, so I'm not sure what's going on. The whole line is out because I have a few lights along it and none are working.

Any ideas? Or is it time to call professionals? I'm pretty good with wiring but have little experience with circuit breakers and switch boxes.

  • Hello, and welcome to Home Improvement. What do you mean by "the test is working"? Have you tried an outlet tester on the saw's outlet? And, you should probably take our tour so you'll know how best to participate here. – Daniel Griscom Jan 4 '20 at 1:42
  • Faulty neutral wire somewhere. Possibly in the panel. – Harper - Reinstate Monica Jan 4 '20 at 2:12
  • @DanielGriscom there's a "test" button on the breaker itself. After the accident when pushed nothing was happening, breaker would stay in "on" position. It started to work when I replaced the circuit breaker – Bostone Jan 4 '20 at 2:33
  • Can you turn the breaker off, then use a multimeter to measure for continuity between the white and bare wires on that circuit after making sure the circuit is powered off? – ThreePhaseEel Jan 4 '20 at 3:14
  • @ThreePhaseEel When I turn the breaker off the non-contact tester stops detecting any current in either black or white wire I'm not sure how to check for continuity between white and bare wire? All I have at my disposal is a current tester and voltmeter – Bostone Jan 4 '20 at 4:00

You have an open neutral somewhere in the line

From the meter readings you took with the breaker off, namely no continuity between any pair of wires, even neutral to ground which should have a low resistance between them since they are connected at the main panel, as well as the neutral "ringing" as hot with a non-contact voltage detector, it sounds like you have an open neutral somewhere. I would go down this circuit from the failed point towards the beginning, replacing failure-prone backstab connections into receptacles with proper shepherd's hooks around the side-screws instead, and making sure there isn't a failed wirenut splice somewhere, either.

  • Say I have failed backstab at one receptacle. How that explains that none of my lights along the line come up? Should I start at the switchbox? – Bostone Jan 5 '20 at 5:34
  • @Bostone -- whatever splice failed, failed early on in the circuit, you can have receptacles upstream of lights, after all – ThreePhaseEel Jan 5 '20 at 15:33
  • I'm going through this switch by switch tonight. What puzzles me is this is as you say open neutral why there's a current that I detect with voltmeter between neutral and ground? – Bostone Jan 6 '20 at 16:06
  • @Bostone -- you're detecting voltage from neutral to ground because current cannot flow down the neutral – ThreePhaseEel Jan 6 '20 at 23:16

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