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?
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).
Here is what the trouble may be, and what you can do about it:
- The ground wire at the troubled outlet could be connected to a hot wire. This is not likely, but it would be quite dangerous. You can disconnect and tape the ground wire and replace the outlet with a GFCI. Apply the label "ungrounded GFCI" that comes in the box. The ungrounded GFCI will protect against shock, but provide less protection to electronics connected to that plug than would a proper ground. (Ditto for any other outlets you connect downstream from it.)
- The bare ground wire at the troubled outlet may not be connected to anything. Some voltage detectors cannot tell the difference between a connection and capacitative coupling, which is what you get when two wires run close to each other without being connected. Your ground wire is running in the same sheath at the hot wire and picking up enough voltage to show up on your voltmeter device. You could try to find the other end and connect it to the ground there. If you know where the power is fed from, start at that point and work your way. If you don't know the path and don't know how to trace it, open each outlet until you find it. You might also need to look in junction boxes where wires interconnect without receptacles to see if there's an unconnected ground wire. If you still can't find it, you can use the same work around in #1 above, lifting the ground wire and installing a GFCI with the "ungrounded" label.
Please be safe, and double check all power is off before you open the outlets.
(I'm not an electrician; I've taught electrical engineering technology at the college level and have a relevant consulting practice with an R&D lab.)