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  1. #1
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    Default Voltage on ground

    I found 85v on neutral to ground, 15v on hot to ground, and 120v neutral to hot.
    This is on a grounded outlet, but it does not have a ground wire (2 wire ungrounded system). Downstream outlets seem OK, similar readings on the only upstream outlet.
    How can there be a voltage reading on ground without a ground wire connected?
    BTW This is one of the 3 evictions I posted about a few weeks ago. Just had the power turned on to do some work.
    Thanks

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  2. #2
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    Default Re: Voltage on ground

    The only way I know that you can get voltage on a ground with a two wire system is with a false ground (neutral has a jumper to the ground).

    Scott Patterson, ACI
    Spring Hill, TN
    www.traceinspections.com

  3. #3
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    Default Re: Voltage on ground

    Thanks Scott
    My thoughts also.
    I'm going to go back and check it again. I must have overlooked something.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  4. #4
    Richard Moore's Avatar
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    Default Re: Voltage on ground

    Quote Originally Posted by fritzkelly View Post
    Then how would you get 85v neutral to ground? Maybe the receptacle is cracked or broken.
    Also..."similar readings on the only upstream outlet."

    I don't see a bootleg ground giving the readings Rick found. Just a guess, but I'd suspect old metal boxes, AC between the two boxes, and a partial short from the hot to the metal somewhere. Maybe deteriorated insulation?

    Time for an electrician!


  5. #5
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    Default Re: Voltage on ground

    Quote Originally Posted by Rick Cantrell View Post
    How can there be a voltage reading on ground without a ground wire connected?

    Presuming you are actually stating that there is no wire connected to the ground terminal off the receptacles, the only way to get voltage on the ground terminal is a defective receptacle.

    I'll simplify what I am meaning:

    Hot wire to receptacle hot terminal
    Neutral wire to receptacle neutral terminal
    *no* wire to receptacle ground terminal

    Regardless of what voltages are being brought in (referring to Richard's explanation, which I liked at first) those voltages will be applied only to the terminals to which each of those conductors are connected. With no connection to the ground terminal, there would be no voltage on the ground terminal - regardless how much, or how little, voltage was between hot and neutral.

    Thus, the only way to get voltage on the ground terminal would be an internal or external fault at the the receptacle (as Fritz suggested).

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
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  6. #6
    Richard Moore's Avatar
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    Default Re: Voltage on ground

    Jerry, the ground hole (technical term ) of a grounded receptacle is connected to the receptacle chassis. Assuming metal j-boxes, the receptacle mounting screws would connect the ground to the box and subsequently any metallic conduit between the two bad outlets.

    As I said, just a guess, and not saying I am right or you are wrong, but both a bad receptacle or a fault in the hot elsewhere could be the possible culprits.


  7. #7
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    Default Re: Voltage on ground

    Quote Originally Posted by Richard Moore View Post
    Jerry, the ground hole (technical term ) of a grounded receptacle is connected to the receptacle chassis. Assuming metal j-boxes, the receptacle mounting screws would connect the ground to the box and subsequently any metallic conduit between the two bad outlets.
    True, but I envisioned Rick holding the receptacle out from the box ... because that is how he knows there is no ground wire attached.

    If he did not measure the voltages when the receptacle was out from the box too, and only measured them while the receptacle was installed in the box, a metal box, then, yes, I can go with your description ... which is why I said "(referring to Richard's explanation, which I liked at first)" ... then I envisioned Rick holding the receptacle away from the box and ... thought about it differently.

    Maybe Rick can enlighten us as to how he measured the voltage and verified there was no ground wire?

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
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  8. #8
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    Default Re: Voltage on ground

    I'm not feeling well right now, sore throat, general aches and pains, coughing,etc.. In fact I was sick yesterday when I posted. The description was/is not very accurate. I'll go back to check it in a few days.
    But to answer some of the questions:

    True "Hot wire to receptacle hot terminal"
    True "Neutral wire to receptacle neutral terminal"
    Mostly true "*no* wire to receptacle ground terminal"
    No ground wire to panel, there is a ground wire that is connected to a receptacle 2' away (12-2 with ground romex, surface mount raceway)
    So the two receptacles have a ground connected between them, but not to the panel. Both outlets read the same.

    "True, but I envisioned Rick holding the receptacle out from the box ... because that is how he knows there is no ground wire attached."
    Yes, I pulled the receptacle out of the metal box.

    "Then how would you get 85v neutral to ground? Maybe the receptacle is cracked or broken."

    "Thus, the only way to get voltage on the ground terminal would be an internal or external fault at the the receptacle (as Fritz suggested)."

    This sounds like the most likley cause.

    Thanks
    Gotta go to bed now
    BTW today is my Birthday (51) and I'm sick

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  9. #9
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    Default Re: Voltage on ground

    Quote Originally Posted by Rick Cantrell View Post
    BTW today is my Birthday (51) and I'm sick
    Well, Mr. Sick Guy, have a better day, and feel better tomorrow.

    Your problem is just that you feel to young, and, at only 51, you are thinking you can still do all those things you used to do - and that made you sick.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  10. #10
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    Default Re: Voltage on ground

    I don't know if this is the same situation I ran across a few years ago?

    Three way switches had been mis-wired by DIY homeowner. It was such a CF that I pulled the whole mess apart and started from scratch. I did not take the time to diagram what caused the voltage between N & Gnd but think the wire used as Gnd was really a traveler of the three ways. Depending on where the mis-wire occurs you can measure across an individual load when you go between N & Gnd at the receptacle. If there is a 100w and a 60w light then you would measure about 85v across the 100w light at the N to Gnd.

    As I said I did not analyze it at the time, just too hard to do by your self with switches across the room.

    Last edited by Vern Heiler; 11-24-2008 at 09:17 PM. Reason: 85 across wrong light..

  11. #11
    Shannon Guinn's Avatar
    Shannon Guinn Guest

    Default Re: Voltage on ground

    Rick, Happy Belated Birthday! Hope you're feeling better.

    Now back to work!

    Regarding the "screwy" issues at the house you referenced, something I used to see all the time here in GA and it may have already been mentioned would be that if it was an older two wire 120V branch circuit with grounding type receptacle, I would look for the jumper from the neutral side to ground screw. Some people would rather pay 50 cents rather than 3.00 for the right part. If that's not it, I'm sure you'll check for loose neutrals, loose etc. or if it is an older house with the old "white is hot" in SLs going to light fixtures, who knows what you'll really find.

    Who said code and licensing requirements were unnecessary?


  12. #12
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    Default Re: Voltage on ground

    I was reading some of my old post and came acrose this one.
    I said that I would check it again and repost what I found.
    Sorry for the delay.
    Anyhow, The outlet was a (get this) Jerry Rigged surface mount addon.
    I replaced the receptical and all was well.
    BTW I'm feeling better now.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

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