[Toga]

Line tester shows open ground on several wall outlets on same breaker. Test meter shows voltage across hot/neutral on all shows 120. Voltage across hot/ground shows 52/53 volts on same outlets. I tested all outlet hardware on good circuit and all show 120 volts with no open ground. In service panel I tightened all neutral and ground leads paying particular attention to the circuit and breaker in question.
I have never seen this before and I am looking for any suggestions.
Thanks in advance! TM

 

[Missouri Bound]

Line tester shows open ground on several wall outlets on same breaker

Are there any on that breaker that have a good ground?
Is your wire in conduit or is it cable?
If all of your outlets on that one breaker are without ground....start at the panel.
If some of them then you will have to open each box and test.

 

[Toga]

Are there any on that breaker that have a good ground?
Is your wire in conduit or is it cable?
If all of your outlets on that one breaker are without ground....start at the panel.
If some of them then you will have to open each box and test.

MB Thanks for the reply.
Standard house wiring behind drywall.
Two outlets on that breaker test OK. Five other drops tested Open. I have replaced "Open" outlets with new outlets and Ohm tested OK. Still same result. I'm beginning to think I have drops on that breaker I have yet to identify.

The question I'm really puzzled by is why do the "bad" drops test at
52 to 53 volts from hot to ground. I don't get that. I would think if the ground were bad the reading would be zero. The 52/53 reading is consistant on all the "bad" drops.

 

[dmxtothemax]

QUOTE - The question I'm really puzzled by is why do the "bad" drops test at
52 to 53 volts from hot to ground. I don't get that.


I can think of two reasons
1 - the connecttion is NOT completely open circuit,
instead it has gone high resistance, enough for 50v to get thru !


2 - The 50v isn't really there, instead your reading ghost voltage.


check google or wiki for explanations of ghost voltage.
:glasses:

 

[FrodoOne]

Are you using a Digital Voltmeter or an Analog Voltmeter?

What voltage is measured between the Neutral and the Ground and why have you not measured this already?

 

[Toga]

Are you using a Digital Voltmeter or an Analog Voltmeter?

What voltage is measured between the Neutral and the Ground and why have you not measured this already?

I'm using a Fluke 117 dvm. Not sure why that matters. Haven't measured the Neutral to Ground as it never occurred to me. I would expect it to be zero or very low. Still trying to figure out next troubleshooting steps. I'm thinking disconnect ground from last drop in circuit and connect it to known working ground on another circuit. If that checks out then move up the line to the next and repeat until I come to a drop which fails. I'm open to any troubleshooting suggestions.

Thanks for everyones input. This will be a good lesson once resolved.

 

[RAL238]

On your Fluke 117, are you using the AutoV-LoZ setting or the AC V setting? It makes a difference. LoZ will give you an accurate reading. AC-V is high impedance and can be subject to phantom voltage readings.

 

[FrodoOne]

Line tester shows open ground on several wall outlets on same breaker. Test meter shows voltage across hot/neutral on all shows 120. Voltage across hot/ground shows 52/53 volts on same outlets.

Haven't measured the Neutral to Ground as it never occurred to me. I would expect it to be zero or very low.

If you measure 120 V from Line to Neutral and 52 V from Line to the "Ground Wire", why would you not expect to measure (120 - 52) = 68 V from Neutral to the "Ground Wire". (assuming that the Voltage which you are "reading" from Line to "Ground Wire" is a real low impedance reading and not a high impedance reading of a "Phantom" voltage.)

 

[Toga]

If you measure 120 V from Line to Neutral and 52 V from Line to the "Ground Wire", why would you not expect to measure (120 - 52) = 68 V from Neutral to the "Ground Wire". (assuming that the Voltage which you are "reading" from Line to "Ground Wire" is a real low impedance reading and not a high impedance reading of a "Phantom" voltage.)

Finally called in a pro and he had fixed in short order. All drops now show good ground at 120v. Thanks for everyones input!

 

[cvh4878]

Finally called in a pro and he had fixed in short order. All drops now show good ground at 120v. Thanks for everyones input!

Did he say what specifically was causing the issue? Just curious

 

[Toga]

The pro said it wasn't worth the time trying to figure out where the "ground break" was located. He simply suggested, and I agreed, the easiest solution would be to run a new ground wire between the A) last know working drop on the circuit and B) the first drop showing an open ground. This done the circuit now tests good on all drops. Being a purist I would have preferred to find the exact cause of the problem but at this point I'm glad it is finished. :smile: