Current on cable tv's ground 2

[meterman3]

We have a apartment building complex in our electrical distribution system. The problem area has 3 buildings with 4 apt. each. We have current leaking onto the cable tv's ground causeing pixelation and dropped calls. The current is only 1-3 amps .5 amps is the high limit. We have added 8' rods at the pad mount and bonded more at the feed through transformer and at the riser. The neutral is parellel 2/0 and in good condition with a 1/0 copper ground back to the pad mount approx. 80' away. Also the service at each building has a rod and is bonded to the water system. Any ideas?

 

[waross]

Start following the TV cables to find the source of the current. There may be a device on the cable system that is failing. It may be an induction problem.

Bill
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"Why not the best?"
Jimmy Carter

 

[jghrist]

You may be getting primary neutral current unbalance in the ground system. This could possible if the primary neutral has a high impedance. Check to see if there are any bad neutral connections on the primary feeder serving the complex.

 

[7anoter4]

I think since most of apartment loads are single phase loads, the phase currents are uncontrolled and unbalanced and a neutral current will be always circulated through the neutral conductor.
If the neutral conductor is grounded at both ends -transformer side and at the building side- and if also the TV grounding conductor [or shield] is grounded both ends, then the two parallel conductors will shared the neutral current inversely proportional with their impedance. You have to insulate one of the ends-my opinion on both conductors.