Electrical Question


Is it normal to have some residual voltage, under 5 volts, between the neutral and the ground? Voltage between hot and neutral and hot and ground is 120v.
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Check out this Fluke article and see if it answers your questions:
http://support.fluke.com/find-sales/Download/Asset/1989076_6003_ENG_C_W.PDF
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Insufficient info: Is that with current flowing to something plugged into that circuit???? Or is it with that circuit breaker off??? Because with even a cheap meter there can be small induced voltages from other wires that are working, running parallel in the same area etc. on even a so called dead or disconnected wire. Also maybe on one side of a working Edison circuit! Description of the situation; where and under what conditions the voltage was measured etc. would help. Five volt drop on a working circuit with something actually plugged in and working (current flowing) does sound a little unusual, and might suggest a high resistance connection somewhere to be investigated for a faulty item.. However a 5 volt drop on a working circuit drawing say 10 amps suggests a resistance of around 5/10 = 0.5 ohms which for 12 AWG is approx 300 feet of single conductor copper. Is the conductor under size or does the circuit go through a lot of duplex outlets etc. before the point of measurement? Older backstab outlets are often mentioned here. Not aluminum wiring perhaps? Hard to comment.
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Steve-
Help me here....I followed the link and was in the process of reading it (and, of course, looking at the figures)
Is the figure properly annotated? the "hot-neutral reversed" figure has two leads labeled as H.....
am I mis-reading it or what?
thanks
cheers Bob
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On Wed, 21 Oct 2009 23:28:43 -0500, Steve N. wrote:

Yup. The 3v max is right about what it is at, as I recall. The needle moved, but not to a full 5v. It appears to be within normal.
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*I wouldn't call that normal, but I have found that sometimes. Make sure all of your grounds and neutrals are tight in your electrical panel.
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On Thu, 22 Oct 2009 08:02:45 -0400, John Grabowski wrote:

They are all tight.
As far as under 5v, the needle moves on some outlets when measuring neutral to ground. I know that either ground or neutral will pick up stray induction voltage when running along metal beams.
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*Try the same testing with your main breaker off so that no current is flowing in the house. I'd be interested in what your results are.
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Michael Dobony wrote:

Using DVM? Not a good choice in a case like this. Good old analog meter is still very useful!
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The neutral and ground are tied together at the service entrance, and should not be tied together anywhere else. So if you measure the neutral to ground voltage at some point distant from the service entrance, and there is any current on the neutral conductor anywhere between your measurement point and the service entrance, you will see a voltage difference. This is due to the voltage drop from the resistance of the neutral wire carrying that current.
Cheers, Wayne
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On Thu, 22 Oct 2009 20:29:55 +0000 (UTC), Wayne Whitney

Yeah. What he said. You most likely have a clock or a lamp down the line from the outlets you are measuring > 0.
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On Thu, 22 Oct 2009 20:29:55 +0000 (UTC), Wayne Whitney wrote:

No, ground is separate from neutral, per code.
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If your grounding system has no connection to the neutral anywhere, then it is not very useful. The grounding system should have exactly one connection to the neutral, at the service entrance. The primary point of the grounding system is to complete a short circuit should a live wire accidentally contact the grounding system, thereby opening the breaker for the circuit. For that to happen, you need to have the ground bonded to the neutral at the service entrance.
Yours, Wayne
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Michael Dobony wrote:

Essentially neutral and ground is tied together. Ideally it should read 0 volt but 5V seems too high. If you can light a small low voltage bulb, that is bad.
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On Thu, 22 Oct 2009 18:49:05 -0600, Tony Hwang wrote:

No, code is now neutral and ground need to be separate. Ground is connected only to the grounding rod.
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