Open ground - how best to trouble shoot

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Old 07-08-18, 05:12 PM
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Open ground - how best to trouble shoot

I've found a circuit that is testing as "open ground". There are 7 outlets and one ceiling light on the circuit. All 7 outlets test open. The house was built in 1980 and has been added onto several times so the wiring is not always logical.

I've opened each outlet and they appear to be wired correctly - no loose wires. One outlet is a metal box and the box is grounded, the others are grounded directly to the receptacle.

What can I try next?

Would a GFI breaker solve the problem?

Thanks.
 
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Old 07-08-18, 06:20 PM
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Would a GFI breaker solve the problem?
A GFI breaker would be like putting a band aid on a missing ground.

What do you have for wiring..... BX, conduit, NM-b(romex) ?
 
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Old 07-08-18, 07:41 PM
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Originally Posted by PJmax View Post
What do you have for wiring..... BX, conduit, NM-b(romex) ?

Yeah, wasn't sure on the breaker. It's 12-2 romex.
 
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Old 07-08-18, 08:11 PM
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So newer type wiring. That means you'll need to go to the first location and check for ground there. The first location will usually be the closest point to the panel. You're going to be troubleshooting using an ohmmeter to check from ground to the white neutral wire. You should measure close to 0 ohms.... which is a short. This testing is done with that circuit power turned off.
 
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Old 07-09-18, 10:25 AM
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Ok, I'll give that a try when I get a bit of time this afternoon. I'm going to guess that all the outlets will show a short. If that is the case, does that mean the open ground is somewhere between the first outlet and the breaker box...or in the box itself?

Thanks for the help.
 
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Old 07-09-18, 10:33 AM
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No.... all the receptacles will not show a short between neutral and ground. The only connection between the two is at the panel.
 
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Old 07-10-18, 12:40 PM
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OK, I got out my multimeter - I am far from and expert with this thing - and set it to read ohms. I touched the red probe to the white wire and the black to the ground wire. I did not get 0. There was a reading that varied. All 7 outlets were like this.

Just because it was fairly easy... I replaced the breaker with another and there was no change to the "open ground" fault.

I traced the wires in the breaker box and they are all secured where they need to be.

Advice on what to try next? I sure appreciate the help!
 
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Old 07-10-18, 07:20 PM
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OK, I got this fixed. All outlets are testing as "wired correctly". Here's what I did...

A friend suggested a test... Run a wire from a ground in a good circuit to a ground in the circuit with the open ground. I did this and all outlets on the problem circuit tested good. So what I did was run a wire from the ground in the ceiling box for the light to an adjacent ceiling box, connecting the grounds. This has grounded the problem circuit and they all test good.

Is this an appropriate fix? Seems to me a ground is a ground...
 
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Old 07-10-18, 07:38 PM
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Make sure you have a non-contact voltage tester to test for voltage and power off the circuit breaker before working on the outlets.

Could you verify that the ground wire (green or bare wire) is present in the outlet box you tested and is the box plastic or metal? Is this a three-prong outlet? Also, verify that the electrical wire to the circuit has at least three wires: black, white and green(bare copper).
Please check out this video for a better understanding - How To Fix a Receptacle With an Open Ground
Good luck. I had an open ground receptacle and noticed it didn't have a ground wire. Once I wired the ground wire, it tested fine.
 
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Old 07-10-18, 07:41 PM
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Originally Posted by aces-n-eights View Post
OK, I got this fixed. All outlets are testing as "wired correctly". Here's what I did...

A friend suggested a test... Run a wire from a ground in a good circuit to a ground in the circuit with the open ground. I did this and all outlets on the problem circuit tested good. So what I did was run a wire from the ground in the ceiling box for the light to an adjacent ceiling box, connecting the grounds. This has grounded the problem circuit and they all test good.

Is this an appropriate fix? Seems to me a ground is a ground...
I am no electrician, but I would ground it to another metal box on the same circuit. Your solution could be fine as well. We'll wait for the experts.
 
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Old 07-10-18, 08:10 PM
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I am no electrician, but I would ground it to another metal box
That will work only if the box is grounded. If it is you should connect the new ground wire to the other grounds in the box with the good ground. (The box also would need to be pigtailed to those grounds.) Under old code you would need to go back to the panel but under recent code you can go to the nearest good ground.
 
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Old 07-11-18, 08:53 AM
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Excellent! Thank you guys.
 
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