To add to what Mrderrick said, it is apparently common for installers to ground the entry point of the cable system to whatever is handy. Breaker boxes, water pipes, gas lines, your neighbor's electrical system... I've seen all these done. If the desire is to fix the problem rather than patch it this is the place to look first.
BTW, I am NOT an electrician nor do I have any official training in this area. Before doing anything it is best to ask questions. This is electricity and the penalty for mistakes may be severe.
BTW, I am NOT an electrician nor do I have any official training in this area. Before doing anything it is best to ask questions. This is electricity and the penalty for mistakes may be severe.