What would this be?

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This has to be an induced voltage from something maybe even the test meter its self.IMO,,,,, hence Phantom Voltage,at play possibly?

Voltage potential reference to ground should be "0" when measuring from the grounded conductor to the grounding conductor

dick
 
dicklaxt said:
This has to be an induced voltage from something maybe even the test meter its self.IMO,,,,, hence Phantom Voltage,at play possibly?

dick
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Could be likely ,.we don't have enough to go on... though one load is a motor ...

http://www.coleparmer.com/techinfo/techinfo.asp?htmlfile=Fluke-volt-affects.htm&ID=292

Stray or ghost voltages occur from capacitive coupling between energized circuits and non energized, non connected adjacent wiring. Because of this coupling effect and the multimeter?s high impedance, it?s not always possible to determine if the circuit under test is energized or de-energized, and this creates confusion for the person performing the test.
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iwire said:
So I have to ask, Why would you assume it's 'Midwest pool panel' and why would you assume enough current on the EGC to cause 5 volts of drop? :-?
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Midwest is the most highly visible panel pushed by the supply houses by me lots of displays and heavy marketing so I would assume they sell in other parts of New York also. Just my gut feeling by information provided. They make a pretty nice panel.
I did not say that all of the voltage drop would be on only the ground alone but the measurement he said he took was neutral to ground and there are a number of reasons why there would be undesireable current on either wire. It seems that many electricians overlook the possibility of current running on the green conductor. It would be easier to generate a higher voltage drop on a substantially smaller wire and this drop seemed too high for a #4 120 ft long.
 
iwire said:
I did not see anything the tells us what the load on the neutral is.
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True - which why I was asking why/what is this person testing for.

dicklaxt said:
This has to be an induced voltage from something maybe even the test meter its self.IMO,,,,, hence Phantom Voltage,at play possibly?

Voltage potential reference to ground should be "0" when measuring from the grounded conductor to the grounding conductor
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I just do not believe in ghosts - if there is a measured voltage there - it is there, be it capacitive or induction, it is there - usable as if it would sustain any load - different story - still not a ghost.... Might be enough to give you a really neat ground loop hum, or effect sensitive electronics. But not enough to show up on your Wiggy...

LarryFine said:
Why would the EGC have any voltage drop?
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It too is a return path for testing purposes here, and one often of a smaller conductor, and with often many more connections. (Some that are often paid less attention to.) Sure you will get zero right there in the main panel, but then put a few dozen connections, some through conduit lock-nuts, and various bars, and yes you will get some losses, take that another hundred feet, and get some more, put some/any current on the neutral and you are going to have differences. Same can be said for the neutral it self - testing both together at a distance is that - testing them both.

dbuckley said:
I would repeat the voltage measurement with the supply off, and see if the voltage changes. That will determine if its volt drop is due to neutral current or ground current.
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I aggree, but first I would do it with the supply on, and no load - then supply off.

I would spend more time thinking about the voltage drop on the hots, and neutral than the ground if there are worries - start there....
 
Pierre,

While the measuring is going on hot & heavy, how about some current readings on all 4 conductors.
 
e57 said:
But not enough to show up on your Wiggy...
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Which is why I continue to use my Knopp K-60 (now CAT-III rated).

LarryFine said:
Why would the EGC have any voltage drop? :-?
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It too is a return path for testing purposes here, and one often of a smaller conductor, and with often many more connections. (Some that are often paid less attention to.) Sure you will get zero right there in the main panel, but then put a few dozen connections, some through conduit lock-nuts, and various bars, and yes you will get some losses, take that another hundred feet, and get some more, put some/any current on the neutral and you are going to have differences. Same can be said for the neutral it self - testing both together at a distance is that - testing them both.
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Oh, I didn't realize you were intentionally loading the EGC.
 
LarryFine said:
Quote:
Quote:
Originally Posted by LarryFine
Why would the EGC have any voltage drop? :confused:

It too is a return path for testing purposes here, and one often of a smaller conductor, and with often many more connections. (Some that are often paid less attention to.) Sure you will get zero right there in the main panel, but then put a few dozen connections, some through conduit lock-nuts, and various bars, and yes you will get some losses, take that another hundred feet, and get some more, put some/any current on the neutral and you are going to have differences. Same can be said for the neutral it self - testing both together at a distance is that - testing them both.
Oh, I didn't realize you were intentionally loading the EGC.
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Failing to get your point.... Mine was if you are measuring potential differences N-G at long distances from the main bonding jumper that there will be just that. Difference's in potential.... Neither conductor is identical - and in this case carrying an unknown current. And 5 volts... I do not see it as consequential for some applications... Nor do we know the full testing circumstances.
118 ft from its source. The conductors are 4 AWG, with an actual load of around 16-19 amps.
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Was this all on one phase???? Is the ground conductor resistive? Is the neutral?
 
Hello,...pierre ,... you out there ?? The question you asked is wicked open ended ,..can you please offer more information ...
 
I asked my friend this who happens to be the smartest man I have ever known,,,,here's what he contributes.

Quote:

From neutral to ground? That sounds like you're out in the middle of a circuit, some distance from your breaker panel, and the neutral is carrying a load back to the panel but the ground isn't. Because of the resistance of the wire, the neutral will never show zero volts to ground at the load connection.. and if measured at any point between there and the panel, will show gradually diminishing voltage as you approach the panel. Only at the one common ground connection will the neutral read zero volts to ground.

Visualize the hot leg as a long series of very low-value resistors, the neutral leg as another, nearly identical series of very low-value resistors, and the load itself as a relatively high-value resistor. At any point between the hot leg's connection and the neutral leg's connection, you'll be able to measure some amount of voltage with respect to ground.


Sounds right to me

dick
 
I absolutely agree that, unless there is zero load on the neutral, there will be voltage drop along that neutral. Plus, it's correct to read that voltage to the EGC.

But that does not mean there is voltage drop on the EGC. That can only occur with current traveling on the EGC, which is an abnormal condition. Of course, it happens.

The real test would be to bring an independent conductor directly from the service neutral bonding point, and use that as a voltage reference against which to test.
 
Or you could just mneasure the voltage difference with the power off, as I suggested earlier; if there is still a potential difference then it is very likely current flowing along the EGC, which although "abnormal", isn't exactly uncommon...
 
Thought for the day. Is there high voltage underground distribution in the area? It may very well be leaking picking up on the pool grounding grid and heading back to a better ground like say the bond jumper to a metalic water delivery system . I would clamp that green wire to see if this is the scenario.
 
dicklaxt said:
I asked my friend this who happens to be the smartest man I have ever known,,,,here's what he contributes.
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With that being the case, there's probably not much reason to question it any further. :wink:

Roger
 
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