# Voltage between Neutral and Ground



## macmikeman

Scanlon Electric said:


> OK, I have my own thoughts on this situation,
> but I am looking for others to put there 2 cents in.
> 
> Here is what I do know:
> 1) The wiring maybe tied to an old two wire system, but the wiring in the box is 12-2 NM with ground.
> 
> 2) One or more outlets are on this circuit and at least one has the same voltage noted below.
> 
> a) When I meter between the hot and neutral I get a voltage reading of 119VAC
> b) When I meter between the hot and ground I get a voltage reading of 100VAC
> c) When I meter between the neutral and ground I get a voltage reading of 14VAC
> 
> 3) I don’t know what other load, if any, is on this circuit.
> 
> 4) There are three switches that are feed by the line side of the GFCI.
> 
> 5) Each one of the switches controls one function of a combination bath fan, heater, and light unit.
> 
> 6) The old GFCI (after I connected the ground wire to it) did not trip when GFCI was tested.
> 
> 7) The new replacement GFCI also does not trip when tested.
> 
> 8) The Fault (red) light of the tester shines brighter when the test button is depressed.
> 
> 9) The meter readings above are on a new GFCI.
> 
> 10) My meter works and is good for general use.
> 
> Note: I have pictures but haven’t yet figured how to post them.
> 
> Thank you for your feedback.


Use an analog meter instead of a digital one. Probably the 14v goes away.


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## BBQ

Scanlon Electric said:


> a) When I meter between the hot and neutral I get a voltage reading of 119VAC
> b) When I meter between the hot and ground I get a voltage reading of 100VAC
> c) When I meter between the neutral and ground I get a voltage reading of 14VAC


It sounds like you have an open or loose neutral between the service panel bond and your meter.


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## wildleg

BBQ said:


> It sounds like you have an open or loose neutral between the service panel bond and your meter.


huh ? have another coffee and try again.

sounds like maybe a poor bonding connection somewhere in the ckt.


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## union347sparky

I had similar problem at a school. Found the previous guy there didn't ground or bond the transformer. Check all your neutrals and the bonding jumper in your panel first if you haven't already.


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## wwilson174

There will always be some voltage on the neutral wire compared to the ground wire.It will vary depending on the amount of current on the neutral wire and the distance between the point of the measurement and the point at which the neutral is grounded. It represents the IR drop on the neutral wire. BillW


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## Semi-Ret Electrician

Scanlon Electric said:


> OK, I have my own thoughts on this situation,
> but I am looking for others to put there 2 cents in.
> 
> Here is what I do know:
> 1) The wiring maybe tied to an old two wire system, but the wiring in the box is 12-2 NM with ground.
> 
> 2) One or more outlets are on this circuit and at least one has the same voltage noted below.
> 
> a) When I meter between the hot and neutral I get a voltage reading of 119VAC
> b) When I meter between the hot and ground I get a voltage reading of 100VAC
> 
> *Poor ground*
> 
> c) When I meter between the neutral and ground I get a voltage reading of 14VAC
> 
> *phantom voltage (because of a poor ground) did you have a low Z meter or try to shunt your meter with a 25W bulb?*
> 
> 3) I don’t know what other load, if any, is on this circuit.
> 
> 4) There are three switches that are feed by the line side of the GFCI.
> 
> 5) Each one of the switches controls one function of a combination bath fan, heater, and light unit.
> 
> 6) The old GFCI (after I connected the ground wire to it) did not trip when GFCI was tested.
> 
> *.Did you push the test button on the GFCI receptacle or did you use your tester? You can't trip a GFCI with a handheld tester, if the ground is missing*
> 
> 7) The new replacement GFCI also does not trip when tested.
> *see #6*
> 
> 8) The Fault (red) light of the tester shines brighter when the test button is depressed.
> 
> 9) The meter readings above are on a new GFCI.
> 
> 10) My meter works and is good for general use.
> 
> Note: I have pictures but haven’t yet figured how to post them.
> 
> Thank you for your feedback.


...........


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## don_resqcapt19

Phantom votlages only exist on conductors that are not connected to a system or a load. If both the grounding conductor and the neutral are connected at the panel you will not see phantom voltages between them.


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## triden

Honestly sounds like a floating ground conductor. The neutral looks like it should be fine, but the ground is raised about 14vac


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## hardworkingstiff

> BBQ said:
> 
> 
> 
> It sounds like you have an open or loose neutral between the service panel bond and your meter.
> 
> 
> 
> 
> 
> 
> wildleg said:
> 
> 
> 
> huh ? have another coffee and try again.
> 
> Click to expand...
Click to expand...

I understood what BBQ said and agreed with it as one of the possibilities. Don't know why you responded that way.


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## wildleg

I was joking about the coffee. I'm not seeing loose neutral. I call it like I see it. If I'm wrong, tell me why.


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## hardworkingstiff

wildleg said:


> I was joking about the coffee. I'm not seeing loose neutral. I call it like I see it. If I'm wrong, tell me why.


I took it to mean the connection between neutral and the regrounding of the neutral to the premise ground. A loose or poor connection between the GEC and the neutral would cause the symptoms reported. A bad connection on the ground conductor (not the grounded conductor) in one of the boxes prior (in the circuit) than the outlet in question would cause the same thing.

Maybe we are all saying the same thing.


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## brian john

wwilson174 said:


> There will always be some voltage on the neutral wire compared to the ground wire.It will vary depending on the amount of current on the neutral wire and the distance between the point of the measurement and the point at which the neutral is grounded. It represents the IR drop on the neutral wire. BillW


 
To have 14 VAC drop between the neutral and EGC you would need 16 amps measured at the end of 225 feet of #12 AWG


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## hardworkingstiff

Scanlon Electric said:


> OK, I have my own thoughts on this situation,
> but I am looking for others to put there 2 cents in.
> 
> Here is what I do know:
> 1) The wiring* maybe tied to an old two wire system*, but the wiring in the box is 12-2 NM with ground.


I missed this the 1st read, it could be there is no ground and the OP is using a DMM picking up inductance in the unconnected ground wire (like others have already posted).


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## wwilson174

Certainly!


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## wwilson174

brian john said:


> To have 14 VAC drop between the neutral and EGC you would need 16 amps measured at the end of 225 feet of #12 AWG


Of course!


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## Big John

I agree with _Hardworking_ the odds look good you don't have a real EGC. Find one, plug in an extension cord, measure against the ground in that, bet it clears up some mysteries.

-John


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## brian john

In reality a good electrician would:

Make a list of all suggestions presented here and rule them out one at a time. To focus on any one issue will often blindfold you to the true problem.


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## Semi-Ret Electrician

brian john said:


> To have 14 VAC drop between the neutral and EGC you would need 16 amps measured at the end of 225 feet of #12 AWG


But assuming just IR drop you would only read 106V at the last receptacle.

I believe the OP has an open EGC.


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## Briancraig81

> c) When I meter between the neutral and ground I get a voltage reading of 14VAC
> 
> *phantom voltage (because of a poor ground) did you have a low Z meter or try to shunt your meter with a 25W bulb?*


I've never heard of shunting a meter before. Can you explain how and why it's done?


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## hardworkingstiff

Briancraig81 said:


> I've never heard of shunting a meter before. Can you explain how and why it's done?


DMM's can read "phantom" voltages and the shunting allows the voltages to dissipate so you will just read the actual voltage.


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## Briancraig81

hardworkingstiff said:


> DMM's can read "phantom" voltages and the shunting allows the voltages to dissipate so you will just read the actual voltage.


I understand that part. So do you touch the DMM leads to the H/N of the bulb while it's set to test volts and then test for your voltage? I guess what I'm having trouble understanding is what shunting is.


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## brian john

Semi-Ret Electrician said:


> But assuming just IR drop you would only read 106V at the last receptacle.
> 
> I believe the OP has an open EGC.


I agree but now you have ruled out issue 1.


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## Wirenuting

Briancraig81 said:


> I understand that part. So do you touch the DMM leads to the H/N of the bulb while it's set to test volts and then test for your voltage? I guess what I'm having trouble understanding is what shunting is.


Put the bulb across the N/G The bulb will not light as the induced voltage isn't there. But the bulbs resistance will use that tiny voltage up.
At the same time read between the N/G to see the real value. 

A multi-able 3 phase run to motors were only 1 motor is running is another place you see it. 
42 volts gets induced from 1 run to the other.


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## Semi-Ret Electrician

Briancraig81 said:


> I understand that part. So do you touch the DMM leads to the H/N of the bulb while it's set to test volts and then test for your voltage? I guess what I'm having trouble understanding is what shunting is.


Yes what you want to do is put a load on the voltage your measuring to confirm it's and actual real world voltage not one being induced into an ungrounded conductor thru inductance, capacitance or leakage. That's why I think the OP has an open EGC.

Many digital voltmeters and some very sensitive analog meters with an input impedance in the 10Meg ohm/volt or greater range read phantom voltages which are very hard for a beginner to understand.

I never drag out sensitive DMM's for simple electrical work. Or, I switch to the "low Z" input mode.


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## wwilson174

Semi-Ret Electrician said:


> But assuming just IR drop you would only read 106V at the last receptacle.
> 
> I believe the OP has an open EGC.


 
The IR drop referred to is only across the neutral wire and does not affect the line voltage, BillW


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## Semi-Ret Electrician

wwilson174 said:


> The IR drop referred to is only across the neutral wire and does not affect the line voltage, BillW


The same current flows in the phase connection as the neutral but only the neutral has voltage drop?


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## brian john

wwilson174 said:


> The IR drop referred to is only across the neutral wire and does not affect the line voltage, BillW


 
If you have VD in the neutral you have it in the line/phase/energized/ungrounded conductor as well.


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## wwilson174

brian john said:


> If you have VD in the neutral you have it in the line/phase/energized/ungrounded conductor as well.


You do indeed, Kirchoff's law tells us that the sum of all the voltages in a circuit equals the source voltage. BillW


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## wwilson174

Semi-Ret Electrician said:


> The same current flows in the phase connection as the neutral but only the neutral has voltage drop?


Not at all, the IR drop I referred to on the neutral was an attempt to explain why there is aways a measurable voltage between the neutral and te EGC.BillW


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## Semi-Ret Electrician

wwilson174 said:


> Not at all, the IR drop I referred to on the neutral was an attempt to explain why there is aways a measurable voltage between the neutral and te EGC.BillW


Only if there is current flow and the EGC is intact back to the SE panel. 14V would be an indication it was not and highly unusual if it was.


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