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I have a home that is about 14 years old so it is better than the knob-and-tube wiring in my last home. However, there are no less than three receptacles in the house that couldn't be used as the outlets weren't dependable. Today I tackled one. I checked the voltage across the wires and it showed 96v which was odd. I flipped every breaker and the voltage never changed. On further inspection, I have 24V between ground and neutral, and 120V between ground and positive.

If someone, upstream, they crossed neutral and ground, that could cause something like this, but why 24V between neutral and ground and 96V between neutral and positive? Can those voltages give further clues to what might have been done wrong?

Help please! Lew

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    It's not "positive" - it's "hot" and it alters from positive to negative and back many times each second, since it's AC (Alternating Current) not DC (Direct Current.) The voltages "just happen" to add up to 120V AC - does that ring a bell?
    – Ecnerwal
    Jun 24, 2016 at 20:21
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    Hello, and welcome to Stack Exchange. Many digital voltmeters are incredibly sensitive, and will measure large voltages that actually have no "ooomph" behind them. Try plugging in a lamp and then measure the voltage across the lamp.
    – Daniel Griscom
    Jun 24, 2016 at 20:27
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    Do those outlets work at all? If not, you may be measuring stray voltages (multimeters have a very high impedance which lets them measure stray voltages induced by nearby wires or electrical noise). Plug a simple load (like a lamp or space heater, not a DVD player) into one of the outlets and measure again.
    – Johnny
    Jun 24, 2016 at 20:30
  • @Ecnerwal AC voltages do not work that way you are now thinking DC. With 120V there is a hot that is the maximum potential from ground or neutral if there are different values the neutral is said to float. Daniel & Johnny do have a clue ++
    – Ed Beal
    Jun 24, 2016 at 21:18
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    @EdBeal - Your knowledge of how electricity works is poor, at best. A floating neutral is at a potential between H&G, and the difference is precisely as described in the question. G-N + N-H == G-H.
    – Ecnerwal
    Jun 25, 2016 at 12:45

1 Answer 1

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DVM's have a problem. Unlike traditional voltmeters which use a tiny amount of current from the circuit to move the needle in the meter, DVM's are self-powered and draw essentially no current.

If you lay two wires in parallel and energize one, the floating, unattached wire will "pick up" a voltage by induction (well, capacitance). This is useless and there's no force behind it (if it wasn't, everyone who lived near high-tension lines would pirate power by laying wires alongside). You won't see that power on an analog meter, because there's not even enough current to move the gauge needle.

So when you measure a circuit with a DVM, you never know what you're looking at. It might be real live power or it might be this phantom.

When this happens, put any load on the circuit such as a night-light or a 3-lamp circuit tester, and measure again.

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