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I bought a house built in 1986. The entire kitchen was open ground. I’ve never messed with electric outlets, and it took some time but I got them all grounded and installed GFCI outlets for my kitchen appliances. I have one more open ground, in the sun room. I decided to open it up and get it connected before I use it for workout equipment. But, the ground wire was already connected. the black and bare copper wire are both detected as a live wire by my voltmeter sensor. I’ve checked the connections and even swapped out the outlet with a new one, yet still shows an open ground. What could be the issue here? I’ve tried looking up similar situations but I can’t seem to find anything on it. Any suggestions? I’m not sure where the wires are connecting to another outlet and I don’t have a tracer or the knowledge to do that. One thing I can say is, the last outlet in the kitchen towards the sun room had 3 sets of wires each with 1 ground, 1 neutral and 1 live wire. Could this outlet be connected to the ground in the sun room?

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    What is your definition of "open ground" and how do you know it is that (and not something else)? What are you doing to ground it? This doesn't make sense, as grounding came in during the 1950s and by 1966 ungrounded wire was banned altogether. What was the underlying issue that made you start looking for problems? Feb 26 at 3:03
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    If you are using a non contact voltage indicator it may detect voltage on all 3 wires and the likely hood increases with distance from the actual ground in the panel, a home built in 86 your sun room should not be connected to the kitchen counter circuits at all. How are you measuring ground?
    – Ed Beal
    Feb 26 at 4:45
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    "the ground wire was already connected" Okay, at one end....what about the other end? Feb 26 at 5:39
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    @steve wellens receptacles on a branch circuit are all in parallel , there is a series or 1,2,3,4 but the connections are all parallel.
    – Ed Beal
    Feb 26 at 15:40
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    @EdBeal Yes, electrically they are in parallel but physically they are daisy chained. If an upstream ground wire is disconnected, the downstream outlet(s) will not have a ground. Feb 27 at 5:41

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It sounds like you are using a 3-light tester. What Harper calls the Magic 8-Ball because a lot of times the labels are meaningless.

Each of the lights is a connection between two of the three wires in the receptacle. Open ground is a fancy way of saying "no voltage detected between hot and ground". That can mean:

  • No ground wire connected. That is usually very obvious.
  • Ground wire is connected to the receptacle but not connected at the other end (previous receptacle or breaker panel). That is a bit harder to track down.
  • Hot and neutral reverse. That actually has a light pattern of its own, because a true hot/neutral reverse (which I found last week in my own house) will register ~ 120V between hot & neutral (like normal) and between neutral & ground (not normal) but 0V between hot & ground (like an open ground).

When a 3-light tester doesn't provide the expected results, the next step is a multimeter. Measure voltage between hot & neutral (should be 120V) between hot & ground (should be 120V) and between neutral & ground (should be 0V). Check the wire colors - this is one place where the colors mean something - and you should have bare or green for ground, white for neutral (larger slot) and black (occasionally red or (if in conduit) some other color) for hot (smaller slot). If that doesn't help you figure it out, check the previous receptacle in the circuit to see if something is messed up there. And if that doesn't work, post pictures and we can try to figure it out.

Each tool - non-contact voltage tester, 3-light tester, multimeter - has a different purpose. There is plenty of overlap, but each one can do something the others can't (NCVT - easy safety test; 3-light tester - easy verification of receptacle wiring; multimeter - detailed diagnosis).

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