Open ground

Dsg319 said:
A low impedance meter will show true/real usable voltage. As it allowed more current to go through it it will cause a voltage drop on small capacitive coupled or induced voltages known as ghost voltage .
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Got it ,but what I still don't understand how would I get voltage from the hot to ground or continuity from neutral to ground if there is no complete ground fault path back to the service and why the solenoid tester is more accurate thanks again
 
The electron man said:
Got it ,but what I still don't understand how would I get voltage from the hot to ground or continuity from neutral to ground if there is no complete ground fault path back to the service and why the solenoid tester is more accurate thanks again
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A "wiggy" or solenoid tester puts some load on the circuit. A multi meter doesn't.

I'll give you an example of ghost voltage. Had a building where we found EMT strapped to a cinder block wall. If you measured from the EMT to an actual good ground, it would show 120volts so you would think the EMT was "hot" but we were measuring it with a Fluke multimeter.

The problem was the "electrician" had stubbed EMT through the block wall into the back of a 4" square box that was flush in the wall. He mounted a fluorescent fixture over the box but with no metal-metal contact between box and fixture and just anchored the fixture to the block wall, so the fixture was not grounded. When we grounded the fixture the ghost voltage went away.

Chances are if we had measured from the EMT to a good ground with a wiggy it would have shown nothing. In fact you could touch the EMT and feel nothing. Grounding the fixture fixed it so it was picking up ghost voltage off the ballast.
 
The electron man said:
Got it ,but what I still don't understand how would I get voltage from the hot to ground or continuity from neutral to ground if there is no complete ground fault path back to the service and why the solenoid tester is more accurate thanks again
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A solenoid tester, often called a Wiggy, is not more "accurate". A solenoid tester can't tell you if you have 118V or 121V or 125V. It can only tell you that you have about 120V or not when you use it to test. Because the solenoid tester has a coil that draws current when energized what it can do is some actual electrical "work". If you leave it on a live circuit too long it will get hot and can be damaged.

A digital multi-meter doesn't do any electrical "work". It draws a teeny tiny amount of current, not enough to make any change to the circuit and converts that to some bits and bytes and puts out numbers on the display for you to read. So it can tell you if you have 120.2V present or 120.234V present. But it can't tell if that is "real" voltage or what we call "ghost" voltage.

Put the leads of a DMM hot to equipment ground on a GFCI protected circuit and it won't trip. Put the leads of a wiggy hot to EGC on the same GFCI circuit and it will trip.
 
The electron man said:
Got it ,but what I still don't understand how would I get voltage from the hot to ground or continuity from neutral to ground if there is no complete ground fault path back to the service and why the solenoid tester is more accurate thanks again
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Your continuity reading may need more investigating as to why.

But if there is not a low impedance path back to the source the voltage you read is because of capacitive effects. The conductors routed right next to each other is basically what a capacitor is, but this happens to be a pretty weak capacitor. A high impedance meter will read the voltage. A low impedance meter will put enough load on what is being tested to drain the voltage away if it is a weak capacitor that is carrying said voltage.
 
Now, I'm not going to tell you how to do this safely, but:
If you connect a small old fashioned incandescent light bulb across the two wires, you can measure the voltage with any Volt meter.
 
ActionDave said:
A solenoid tester, often called a Wiggy, is not more "accurate". A solenoid tester can't tell you if you have 118V or 121V or 125V. It can only tell you that you have about 120V or not when you use it to test. Because the solenoid tester has a coil that draws current when energized what it can do is some actual electrical "work". If you leave it on a live circuit too long it will get hot and can be damaged.

A digital multi-meter doesn't do any electrical "work". It draws a teeny tiny amount of current, not enough to make any change to the circuit and converts that to some bits and bytes and puts out numbers on the display for you to read. So it can tell you if you have 120.2V present or 120.234V present. But it can't tell if that is "real" voltage or what we call "ghost" voltage.

Put the leads of a DMM hot to equipment ground on a GFCI protected circuit and it won't trip. Put the leads of a wiggy hot to EGC on the same GFCI circuit and it will trip.
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My fluke 115 dvm has a low z input.
 
ActionDave said:
. Because the solenoid tester has a coil that draws current when energized what it can do is some actual electrical "work". If you leave it on a live circuit too long it will get hot and can be damaged.
.
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I once had the opportunity to use my solenoid tester on a 600V system - so u know I just had to do it. Boy did that thing jump! 😯. Not sure I would want to leave it connected for more than a few seconds.
 
The electron man said:
Hey so I recently installed 2 gfci outdoors and when I plug in the tester as seen in the pic's below I get an open ground Indication
I checked and I do have continuity between the ground and neutral so I know I have a ground fault path back to the main why am I getting and open ground then
View attachment 2574855
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This has been a long a confusing thread given that the two things you indicate in your first post simply can't both be true. Either the tester's right side LED is burned out or your claim of a low resistance connection between neutral and ground is mistaken. Based on what else you said I lean toward the tester LED being out, in which case throw the tester away.
 
jaggedben said:
This has been a long a confusing thread given that the two things you indicate in your first post simply can't both be true. Either the tester's right side LED is burned out or your claim of a low resistance connection between neutral and ground is mistaken. Based on what else you said I lean toward the tester LED being out, in which case throw the tester away.
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Before you throw it away, plug it into a known good outlet on another service.
 
jim dungar said:
My experience has been that plug-in testers work very well when they tell you everything is good, they hardly ever produce false positives. However, they are pretty poor for troubleshooting, they are fairly notorious for giving false negatives.
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They are very simple devices and give quite reliable info *if you understand how they work* and what the voltages between blades on a standard receptacle are supposed to be.

Quite simply, an energized standard receptacle should have voltage from hot to neutral (middle LED) and from hot to ground (right LED) and *not* from neutral to ground (left LED, red). If you understand that this is what the LEDs represent then they give good info.

The critical thing to understand is that the little legend they give you is inaccurate unless there is only *one* issue. For example, if you have an open ground or an open neutral, you cannot also tell if the hot has been swapped with neutral or ground, respectively. If you have an open hot you usually cannot tell anything about neutral or ground. This is all logically deducible from what you would find using a Fluke or similar and testing each pairing of blades.

As long as you understand these things, then these testers are a convenient and reliable way to test voltage on all three pairings of blades.
 
electrofelon said:
I once had the opportunity to use my solenoid tester on a 600V system - so u know I just had to do it. Boy did that thing jump! 😯. Not sure I would want to leave it connected for more than a few seconds.
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The old ones had a duty cycle based on voltage that was pretty short at 480 volts.
 
jaggedben said:
This has been a long a confusing thread given that the two things you indicate in your first post simply can't both be true. Either the tester's right side LED is burned out or your claim of a low resistance connection between neutral and ground is mistaken. Based on what else you said I lean toward the tester LED being out, in which case throw the tester away.
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And if a digital meter was used on a conductor that has ghost voltage, the resistance reading between the conductors has no meaning.
 
jaggedben said:
That doesn't apply to the scenario in the OP.
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It appears that the only testing device, other than the plug in tester, that the OP has is a DMM. In a number of posts it has been stated that there is continuity between the netural and the EGC.
The EGC is open and has "ghost" voltage on it. Therefore the continuity reading between those conductors, taken with a DMM, is not valid.
He is using that "apparent" continuity to base his expectations of what the circuit should be doing.
 
don_resqcapt19 said:
It appears that the only testing device, other than the plug in tester, that the OP has is a DMM. In a number of posts it has been stated that there is continuity between the netural and the EGC.
The EGC is open and has "ghost" voltage on it. Therefore the continuity reading between those conductors, taken with a DMM, is not valid.
He is using that "apparent" continuity to base his expectations of what the circuit should be doing.
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We don't know what his continuity reading actually is. If he has DMM with a continuity beeper setting, many those only beep when continuity is less than say 50 ohms. If he has a higher resistance than that and is still calling it continuity, which isn't exactly an incorrect statement, he could easily have readings like he has on the plug in polarity tester.

I think it would be best to check voltages with a low impedance meter, if something has a higher resistance to it then it will likely show up as something not expected in those readings.
 
don_resqcapt19 said:
And if a digital meter was used on a conductor that has ghost voltage, the resistance reading between the conductors has no meaning.
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Apples to Oranges.

2 wire 1500 watt milk house heater connected to a 16 Gauge 50' extension cord. I have test pigtails that I can open the EG. Heater on drawing 11.5 amps at 120 volt. Measured voltage at open EG to device equipment ground is 56 volt with Fluke 87. 33 volts with a Fluke 337. No reading with a T+Pro. Resistance with 87 was meaningless. Nothing stable. The 337 showed about 2906 ohms & varied. The T+Pro, nothing.
 
ptonsparky said:
Apples to Oranges.

2 wire 1500 watt milk house heater connected to a 16 Gauge 50' extension cord. I have test pigtails that I can open the EG. Heater on drawing 11.5 amps at 120 volt. Measured voltage at open EG to device equipment ground is 56 volt with Fluke 87. 33 volts with a Fluke 337. No reading with a T+Pro. Resistance with 87 was meaningless. Nothing stable. The 337 showed about 2906 ohms & varied. The T+Pro, nothing.
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That is what I said.
 
kwired said:
We don't know what his continuity reading actually is. If he has DMM with a continuity beeper setting, many those only beep when continuity is less than say 50 ohms. If he has a higher resistance than that and is still calling it continuity, which isn't exactly an incorrect statement, he could easily have readings like he has on the plug in polarity tester.

I think it would be best to check voltages with a low impedance meter, if something has a higher resistance to it then it will likely show up as something not expected in those readings.
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I don't think those work when one conductor has ghost voltage.
 
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