Here is our setup
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Outlet in older house that was replaced with a GFI last year. (no issues until recent)
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The GFI doesn't have a ground wire running up from the basement.
Just the white and black wires. (From my understanding this is an acceptable configuration) -
The outlet reads 119.0v when checked with my multi-meter.
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The outlet reads less than a volt when the "positive" line and the ground are checked with the multimeter. Same with the "negative" with the ground.
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A (real) surge protector plugged into the outlet
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A large tv plugged into the surge protector
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A cox cable box plugged into the surge protector
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A coax cable (run by cox) from the outside of the house, split and sent to a modem and the cable box. The coax reads 0v (no leakage at all) when a multimeter is placed on the inner coax wire and the outer shielding. I tried this on both DC and AC settings on multimetter
The problem:
When either a coax cable or HDMI cable is run from the cable box to the TV, an Arc appears. This has already fried one TV.
My theory:
The coax cable is improperly grounded. I just need a way to prove it. The basis for this theory is the coax cable in a separate apartment tests with an AC voltage of 1.5v. The cable technicians are somehow less informed about circuitry than me. This is a hobby for me so I am lost in the sauce. Any Ideas?
Update
So I took the time to diagram what I have observed. This further supports my theory that the cable isn't grounded properly. I'm not 100% sure how coax is supposed to be run from a telephone pole though so I could be incorrect.
Just in case there is confusion, no the neutral is not plugged into the ground. I was just demonstrating that there is only two wires going to the GFI.
Best Answer
Near where the service enters the house, you should see a grounding block similar to this.
The coaxial cable from the pole/dish/mast should be connected to one side, and the coaxial cable feeding to the house should be on the other side. The screw terminal should have an insulated copper wire, larger than 14 AWG, and shorter than 20' (6 m) attached. The other end of this wire should be attached to either:
If the service is not grounded at the house, it could be (and likely is) at a different voltage potential than the grounding system in your house.