Coax Ground Wire Fried

Phish568

On inspection of why my cable box and lcd tv hdmi input fried, I found the green ground wire on my cable connector outside was severed at both the connector and the inside wall ground post. How could this have happend? Both the connector and the ends of the wires were melted and black, effectively leaving me with no ground on the shared coax line throughout my home.

nap

sounds like there was a lot of current flowing across your grounds. Without some investigation, there is no way to determine if it was from some electrical short or an induced current, a combination of both and maybe a poor connection concerning the green ground wire or maybe even a lightning strike.


If you have an above ground service, I would go to the pole you are fed from to check the ground wire there as well. If it was lightning, it may have caused more problems, like maybe somebody's cable box or lcd tv hdmi input.

Phish568

I live in Sacramento and we rarely get lightning. What we do get is the electric company digging like the movie "holes" all over the neighborhood to fix underground electric cables. I had them in my backyard last month digging a 10'x10' trench to make a repair and the sub electric cable runs right below my Comcast coax...

Had electrical contractors out recently to add to service and upgrade and there is small chance theres an issue with the service. Might have been a poor ground connection though. All incidents with stb failure and burnt hdmi's were the direct result of comcast outages and electrical outages in our area.

dmxtothemax

Some where some time a large amount of current has used the coax
ground wire to return to ground.
Now normally the bulk of the current should follow the mains
earth to ground.
Why has it not ?
Possibly at the time the mains earth was faulty, or non
existant, so the current took the only other path it could find.
CHECK AND DOUBLE CHECK YOUR MAINS EARTH !!!
If you have any doubts get the electric company to check the earth,
and the neutral strap.

nap

absolutely, especially given there was recent electrical work done at your home.

That still doesn't explain why the high current on the ground though but it might help to explain the burned conductor.

joed

Actually if your mains earth is carrying current you have another problem. It should only be carrying current if there is a fault.

However if the workers somehow cut your neutral then the ground wire would attempt to carry all that current.

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AllanJ

On numerous threads I have suggested daisy chaining a long wire from one piece of video or audio equipment to the next and connecting the far end to a known ground (earthing). Damage to your own equipment from cable company problems will be greatly reduced if this long wire includes a "stop" right on the coax shell of the first piece of your equipment that connects to cable company lines.

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