Not sure if I'm using the correct title for this subject but I don't know what else to use to describe it.

Few days ago, while plugging my iron on an receptacle, it generated a sparkle and suddenly stopped working.

This resulted in other outlets and ceiling light around "not working" either. I checked the breaker panel and none of them triggered.

Actually, the very breaker for this receptacle is working well as it secures other outlets in my condo which do not present any problem.

Checking my "defective" outlets with a multimeter, I actually have a voltage value, but not the ones it should be. I have the following readings:

  • Phase (brown) to Neutral (white): 87V (instead of 120V)
  • Phase (brown) to Ground (green): 116V (so apparently normal value)
  • Neutral (white) to Ground (green): 18V (instead of 1.5V)

I have obviously haven't made any physical change on the connection. Does anyone have any idea of where this problem could come from ? thank you in advance for any advice.

  • it sounds like the neutral wire has failed somewhere upstream of that outlet – Jasen Feb 15 '20 at 22:57
  • I checked the receptacle, all wires are properly connected. no sign of damage/burnt. – Sylvain Feb 15 '20 at 22:59
  • trace the wire back to the breaker box. – Jasen Feb 15 '20 at 23:01
  • Thank you all, especially Ed Beal. You were right, the iron did not trip the breaker, but created an arc at a multi-wires connection at the level of a ceiling lamp on the same circuit. I also realized some wires were not properly connected. I disconnected all the wires and connected them back properly. everything is working well now. – Sylvain Feb 18 '20 at 0:02

It sounds like the iron being a larger load may have caused a backstab failure. Under load the voltage dives as it is arcing but with a meter it can appear to be ok but the down stream outlets are not working, pull the receptacle out with the power off. You may find some arc marks or a loose wire, if everything looks ok and you put it back and everything works the receptacle will need to be replaced as when you pulled it out it made good contact. Unfortunately with a heavy load this will happen again and may damage the wires and receptacle if not replaced.

  • I did remove the receptacle earlier: no sign of arc mark, and I have anyway the exact same "weird" voltage measurement at the wire level (receptacle removed): only 87V between neutral and phase – Sylvain Feb 15 '20 at 23:11
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    Go back to the receptacle prior to this one , back stab failure is at the point of failure or the receptacle before it in the chain 98% of the time. If not there it is in the service panel. The receptacle prior may work fine but the feed to this receptacle is the failure point. – Ed Beal Feb 15 '20 at 23:16
  • Great suggestion Ed Beal: While I think it's pretty clearly an open neutral, you provided practical advice in how to determine where the fault is. That's why I love this site. I can contribute at times, but learn so much more. – George Anderson Feb 15 '20 at 23:47
  • you guys are amazing. Nice job. – HoneyDo Feb 16 '20 at 0:14

Sounds like an open neutral. Digital voltmeters are very sensitive. Try putting a load of some sort on one of the "defective" outlets (such as a 60 watt incandescent lamp) and measure the voltages again. This should confirm an open neutral if voltage goes to almost nothing from hot to neutral. (edited)

  • Thanks George. the thing is, nothing turns on when plugged on the "defective" outlet. – Sylvain Feb 15 '20 at 23:01
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    yeah, but try anyway. a broken neutral will measure near 120V if there'a an turned-on appliance connected to it. – Jasen Feb 15 '20 at 23:03
  • So, when I connect a vacuum cleaner (it does not turn on), the voltage between phase and neutral drops from 87V to 0V – Sylvain Feb 15 '20 at 23:06
  • and when the vacuum is connected, my Neutral to Ground rises from 18V to 113V... – Sylvain Feb 15 '20 at 23:08
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    Yep. Sounds like a open neutral to me. I would not expect the appliances to "turn on" just wanted to put a load on the circuit to draw down any tiny currents that could register high on the highly sensitive voltmeters. Your readings are consistent with an open neutral. – George Anderson Feb 15 '20 at 23:23

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