measurable current on cable and ground

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tesla six

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Buffalo, NY
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Licensed Electrician
Dispatched to a business this morning... found 6-11A at the incoming cable company service and going to the 12AWG ground which is clamped to the meter channel.
Service size 3P 120/208V 200A service in a body shop. Looking back I shoulda checked line to line voltage...
today's Line voltage read 130/113/120 to Ground - a little off but looking at the transformers on the pole I'm guessing that playing a part.

- Remove the ground from the meter channel = zero current measured.
- unplugged the energy from the modems, and the load side of the cable company connection no change in readings.
- tightened all panel connections.
- checked for grounding lock nut where service conductors enter the load center.
-turned off all the branch circuit breakers and current reading goes to zero.
-made sure had good ground to main water pipe. Metered 1.5-3A.
-Electric utility visited last week and taped up their connections.
-Cable utility had to replace their termination end because the insulation was melted.
-Tech who visited yesterday said got shock from cable termination. Nothing happened to me. and nothing measurable was present.
-load center desperately needs clean up and better yet replacement, as its filthy inside and 40 years old is my guess. Cloth covered SE conductors.

What are we missing?
Gotta be some wiring some where that needs repairs, a faulty piece of equipment, :blink:
 
tesla six said:
Dispatched to a business this morning... found 6-11A at the incoming cable company service and going to the 12AWG ground which is clamped to the meter channel.
Service size 3P 120/208V 200A service in a body shop. Looking back I shoulda checked line to line voltage...
today's Line voltage read 130/113/120 to Ground - a little off but looking at the transformers on the pole I'm guessing that playing a part.

- Remove the ground from the meter channel = zero current measured.
- unplugged the energy from the modems, and the load side of the cable company connection no change in readings.
- tightened all panel connections.
- checked for grounding lock nut where service conductors enter the load center.
-turned off all the branch circuit breakers and current reading goes to zero.
-made sure had good ground to main water pipe. Metered 1.5-3A.
-Electric utility visited last week and taped up their connections.
-Cable utility had to replace their termination end because the insulation was melted.
-Tech who visited yesterday said got shock from cable termination. Nothing happened to me. and nothing measurable was present.
-load center desperately needs clean up and better yet replacement, as its filthy inside and 40 years old is my guess. Cloth covered SE conductors.

What are we missing?
Gotta be some wiring some where that needs repairs, a faulty piece of equipment, :blink:
Click to expand...
The cable problem could be caused by nearby property connections causing the cable sheath to be forced above remote earth potential.
Or your customer could have a simple sharing of load current between neutral and ground which is causing a similar offset of local ground from remote earth potential.

You need to find a reference to see which contributor is farthest from "ground" first.
 
tesla six said:
Dispatched to a business this morning... found 6-11A at the incoming cable company service and going to the 12AWG ground which is clamped to the meter channel.
Service size 3P 120/208V 200A service in a body shop. Looking back I shoulda checked line to line voltage...
today's Line voltage read 130/113/120 to Ground - a little off but looking at the transformers on the pole I'm guessing that playing a part.

- Remove the ground from the meter channel = zero current measured.
- unplugged the energy from the modems, and the load side of the cable company connection no change in readings.
- tightened all panel connections.
- checked for grounding lock nut where service conductors enter the load center.
-turned off all the branch circuit breakers and current reading goes to zero.
-made sure had good ground to main water pipe. Metered 1.5-3A.
-Electric utility visited last week and taped up their connections.
-Cable utility had to replace their termination end because the insulation was melted.
-Tech who visited yesterday said got shock from cable termination. Nothing happened to me. and nothing measurable was present.
-load center desperately needs clean up and better yet replacement, as its filthy inside and 40 years old is my guess. Cloth covered SE conductors.

What are we missing?
Gotta be some wiring some where that needs repairs, a faulty piece of equipment, :blink:
Click to expand...
You have a problem with a poor connection on the service neutral.
 
The problem isn't necessarily at this location, could be a neighbor with a lost neutral. (Edit: Duh, I just noticed the part Don highlighted. Yes, it's definitely a local problem).

Installing a cable TV ground isolator (prior to the bonding jumper) would eliminate the current.

It should go without saying, but don't leave the cable connected in this state.
 
Last edited:
I agree with Don & Gene. You have a problem somewhere along the line with the neutral and don't leave the cable connected until you find the culprit. You may also end up toasting some electronic components inside the facility if the neutral is faulty. BTW, CATV companies usually will not accept anything over 1A on the ground wire.
 
Gene B said:
The problem isn't necessarily at this location, could be a neighbor with a lost neutral. (Edit: Duh, I just noticed the part Don highlighted. Yes, it's definitely a local problem).

Installing a cable TV ground isolator (prior to the bonding jumper) would eliminate the current.

It should go without saying, but don't leave the cable connected in this state.
Click to expand...

Yes will get the isolator and leave it disconnected. thank you.
 
goldstar said:
I agree with Don & Gene. You have a problem somewhere along the line with the neutral and don't leave the cable connected until you find the culprit. You may also end up toasting some electronic components inside the facility if the neutral is faulty. BTW, CATV companies usually will not accept anything over 1A on the ground wire.
Click to expand...

Well the cable TV tech replaced the connector, reconnected and left with 11A. I was curious what their standards for current now I'm in the know. Thanks.
 
GoldDigger said:
The cable problem could be caused by nearby property connections causing the cable sheath to be forced above remote earth potential.
Or your customer could have a simple sharing of load current between neutral and ground which is causing a similar offset of local ground from remote earth potential.

You need to find a reference to see which contributor is farthest from "ground" first.
Click to expand...

I follow the thought on the shared load current, but I'll have to get them to let me straighten out the panel wires first, because I'm not sticking my hands in there even with proper PPE. Then go through the neutral and equipment grounding conductors.

What I don't have much experience with is your first sentence and your last sentence. By nearby property connections are you saying that other Time Warner cable customers nearby could be having their own poor connections on the electrical service neutral or poor cable tv connection?

Please expound on your last sentence in regards to defining contributor as a reference.
 
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