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Thread: AC electrical puzzlement

  1. #1
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    AC electrical puzzlement

    This morning I plugged in a small electric heater for the bathroom. No sign of life, figured it was either the heater or outlet. I turned off the circuit breaker (after I found it, panel is poorly labeled), removed the outlet and began poking around with a meter. Black to white was 0 volts, I was thinking tripped GFCI. Nope, the outlet that is part of the GFCI is alive. When I checked black to ground and white to ground (bare wire), they both read 125 volts . I have not done anything electrical for months so I don't think it's anything I did. The CB was labeled 'outside outlets' so I checked both of those today and they're dead as well. One of outdoor outlets worked yesterday, I was using it to power some lawn equipment. The cord that powered the lawn equipment is unplugged.

    I haven't opened up the outdoor outlet enclosures yet, that's next. Does anyone have any thoughts about why both conductors would be carrying 125 volts to ground? I'd have thought if something came loose either one leg would be dead or it would have shorted out and tripped either the GFCI or circuit breaker.

    When I replaced the outlet in the bathroom I found the wires were back stabbed. Not with clamps on the back of the outlet, just stabbed into the back of the outlet. I wasn't exactly pleased to find that. The replacement is wrapped around the screws. Everything in the house is functioning as expected except for this one circuit.

  2. #2
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    How many wires in the box? Just one of each?

  3. #3
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    Is anything plugged into any if the outlets in that circuit? Black and white wires are connected wrong somewhere.

  4. #4
    Did you try plugging the heater into a known good outlet? Did you try another appliance in the bathroom outlet?

    The most likely issue is a tripped GFCI. The backstabbed receptacle suggests that it is not a GFCI one, and that it is in a bathroom that it is GFCI protected, so there would be an upstream GFCI outlet or a GFCI circuit breaker.

    It could be the same circuit as the outdoor outlet.

    If there is another load on the circuit the you tested, it could explain the reading. There is another explanation as well. Using a multi-meter on household electrical stuff can sometimes be misleading- too sensitive.

    Occasionally the circuit breaker can be on and has power to it's terminal screw, but the wire is loose and not making contact- checking that the circuit breaker screws are tight is a good idea.

  5. #5
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    A broken, or disconnected neutral wire will cause portions of the the neutral circuit to be energized.

    Regards, Rod.

  6. #6
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    I would de-energize the circuit. Then check each and every device known to be on that circuit to see if any are still energized. If so de-energize that circuit as well. Then starting at the GFCI location open the box and check all the wiring to insure it is properly connected and tight. If any of the receptacles are in a box with another make sure the screws from one aren't contacting the one next to it. Check each outlet in sequence until you locate the problem.
    Lee Schierer
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  7. #7
    Quote Originally Posted by Rod Sheridan View Post
    A broken, or disconnected neutral wire will cause portions of the the neutral circuit to be energized.

    Regards, Rod.
    I think Rod's got it. You have a disconnected neutral, and there is something plugged into an outlet somewhere else on the circuit, causing the hot and neutral to be at the same potential.

    Unplug every load that could possibly be on that circuit (including any lights, etc) and see if the 120V on the neutral disappears. That would confirm that you have an open neutral connection.

  8. #8
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    Then open every box on that circuit and test where you have 120 between the black and white. Probably something as simple as a loose wire nut in the white wires or even a bad receptacle device.

    Itís a fairly common problem with the old back stab receptacles. Bad connection in one of them. Shake the wires because it makes it very hard to find one that completes the circuit when you move it.

    If they are back stabbed, I would just change every receptacle in that circuit.

  9. #9
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    This sounds like it might be a case of reversed polarity.
    They sell little plug ins that you use to check outlets for things like that.
    https://www.gardnerbender.com/en/p/G...eptacle-Tester
    "Life is what happens to you while you're busy making other plans." - John Lennon

  10. #10
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    Quote Originally Posted by Rich Engelhardt View Post
    This sounds like it might be a case of reversed polarity.
    They sell little plug ins that you use to check outlets for things like that.
    https://www.gardnerbender.com/en/p/G...eptacle-Tester
    Yes, this. Inexpensive and if you just plug it into a three prong outlet, will tell you if it is wired correctly, and if not, what the issue is.
    NOW you tell me...

  11. #11
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    You can get them in the box stores too.

    https://www.homedepot.com/p/Klein-To...T210/206517824

  12. #12
    Quote Originally Posted by Rich Engelhardt View Post
    This sounds like it might be a case of reversed polarity.
    They sell little plug ins that you use to check outlets for things like that.
    https://www.gardnerbender.com/en/p/G...eptacle-Tester
    He wouldn't have 0V hot-to-neutral if the polarity was reversed.

  13. #13
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    The tester will tell you if a receptacle is wired correctly, but it won't tell you that it no longer supplies the next one down the line in the circuit unless you know the order in which the circuit is wired. If it's a bad connection in a back stab neutral, you're still going to have to open some boxes up.

    I never heard an answer to the question if anything was plugged into any outlet in that circuit. That will tell us a lot, especially if unplugging whatever that is makes a difference.

  14. #14
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    That's why I said it "sounds like it might be".
    I shy away from most electrical usually.

    I do think one of those little testers is a good idea though.
    "Life is what happens to you while you're busy making other plans." - John Lennon

  15. #15
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    Rod and Dan are correct a open neutral either in the main box or connection after. If all your wiring is back stabbed and daisy chained I would correct that.
    Retired Guy- Central Iowa.HVAC/R , Cloudray Galvo Fiber , -Windows 10

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