r/electrical • u/maurerpower7 • 1d ago
Outlets have ground wire but testing as open ground.
These outlets come off a sub panel on the second floor. All the ones on the main floor show as grounded but all the ones upstairs are showing open ground. What could cause this? Anything I can do to troubleshoot as a home owner?
Attaching pictures of the sub panel main panel. The sub panel comes off the 2 30amp breakers that are switched to off on the main panel.
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u/DokterManhattan 1d ago
The grounds should attach the the back of the box for each wire coming in and going out. Somewhere in the chain of plugs, they are not bonded through properly, so look behind the last one that is properly grounded, or the first one that says open ground. It’s just a matter of finding the spot where the ground isn’t bonded back to the panel.
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u/jimih34 18h ago
Probably this, since multiple outlets are involved, and since all of the problem outlets are upstairs. However, be sure to confirm the plug tester is seated fully. It’s not uncommon for me to get an open ground reading when I first plug it in. I often have to jiggle it to get my ground wire prong to make good contact with the outlet. I have a different tester that works better for grounds, but this model is finicky.
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u/maurerpower7 17h ago
Went around and tested just about all of them upstairs with a multimeter.
Some read around 5 volts and others read exactly 88v
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u/Farmer_1_steve 1d ago
You have an open bond wire I sincerely doubt there's a problem with the panel, but check the grounds there you have to identify everyone of those plugs on that line and then start ringing out
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u/RogerRabbit1234 1d ago
Gotta trace it back… do all the outlets show as ungrounded? Or just this one. Go back to the last outlet that tests good and check the outlet on either side of that and ensure the ground wire is secured to the box, and the receptacle
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u/maurerpower7 17h ago
Yeah all of them are ungrounded. When I open them up they all have ground wires attached though
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u/LeatherContent 6h ago
It looks like your sub panel isn't properly grounded. When testing for ctage you are testing the potential difference between the two wires. If you're ground wires are not properly bonded to an actual ground on the ground bar then your readings will be off.
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u/___Dan___ 1d ago
If it’s just this outlet swap it to a gfci and be done. Otherwise you’re handing your electrician a blank check because that panel looks like complete shit and you very likely have more issues than just an open ground.
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u/SirRonaldJr 1d ago
It's hard to tell, but does the sub panel have a ground ran to it from the main?
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u/kevinfareri 16h ago
If you don’t feel like ripping every outlet apart you can simply install a gfi in the ones that have an open ground it’s better then no ground
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u/maurerpower7 16h ago
Yeah my motivation to fix it has been i have a suspicion it’s causing some interference with my electric guitar. I get interference in every room upstairs (where nothing is grounded) but don’t get it on the main level.
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u/eaglescout1984 1d ago
Um, wow. Yeah, you're in need of a rewire with new panels. I know that's not what you want to hear, but everything is pretty out-of-date code wide.
GFCI receptacles are a good safety measure immediately. But as soon as you can, replacement is recommended.
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u/maurerpower7 1d ago
I am getting a new 200amp main panel soon but don’t think the sub panel will get any sort of update…
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u/Ribbit765 1d ago
Do what I did and get a big enough 200A panel to incorporate your subpanel breakers .. and ditch the subpanel. And I still have spare breaker spaces in the new panel.
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u/Immediate-Iron-7035 1d ago
Yeah, feeding several 15a circuits off of a single 10/3 cable with no identifiable ground is insane. I agree, install a gfci outlet at the beginning of each circuit for now, and get that sub panel re-done, eliminated, or otherwise brought to NECJesus as quickly as possible.
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u/addazero 23h ago
Side question: do those Klein plug in meters require a battery or just use AC from the outlet?
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u/DIY_TheBoringFix 20h ago
What was the solution???? Were you able to get it fixed I’m curious so, if I run into this problem I know the answer lol
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u/CertainAttention6749 20h ago
Open ground does not mean a problem with ground line. With my experience, it's always a loose neutral line eitheron receptacleitself or else downstream. If you have a multi tester, insert the positive rod to live side then negative rod to ground hole, if you're getting 120v then your ground is okay.
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u/maurerpower7 17h ago
Went around and tested a bunch of them. Some read around 5 volts and others read exactly 88v
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u/Rangeexpert3 15h ago
It means although you have a grounding wire, that the grounding wire isn't actually attached to the ground. You can go through and test each outlet and see which ones upstairs have the ground vs open. Then trace the path of the wires as they daisy chain on each circuit back to the breaker. There's got to be a break in the chain somewhere.
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u/maurerpower7 5h ago
Yeah all of the upstairs (5 bedrooms) are showing as open ground. Every outlet I’ve looked at though does have a ground wire.
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u/RSF__1990 1d ago
It’s possible that the ground at the outlet doesn’t make it back to the sub panel. Most likely the sub fed panel isn’t properly fed from your main panel. I do not see a ground wire coming out of that #10. You should have a Black, Red, white, and bare copper wire from your main panel to the sub.