Advertisements If your dwelling is built to code, there is a ground rod that is connected to the main electrical panel. Often, the rod itself is built into the foundation so you might be able to see a big 2 or 4 gauge conductor running up from the foundation somewhere, usually close to the electrical panel. All of the electrical grounds inside the panel are bolted to the metal panel itself. A ground conductor bolted cleanly to the exterior of the panel is adequate since there's a solid connection there. Normally, you would see a 6 or 8 gauge wire running from the electrical panel to your phone and cable demarcation boxes (service boxes) to provide grounds at those points. To inspect the ground block, you would likely need to open the demarcation box. Cable companies lock those service boxes if the "tap" is located there. That's often the case in multi-unit buildings. In single family homes, they don't normally lock the demarcation box since the tap is usually located in a street-side panel. If your cable is not properly grounded at the demarcation point, it's possible grounding somewhere else could reduce a ground problem. A dirty ground can be better than no ground, but it's still not a good idea to ground that way. The only way to properly ground your cable drop is with a ground block wired to the electrical panel. At one point, I was thinking of adding a ground rod myself for a rooftop antenna. With the high potential for lightning strikes, I didn't want to ground it to my home's electrical system. However, I found it's not an easy thing to do. You have to install one with certain materials in a specific way and it can be very difficult to do yourself. It's pretty expensive to have one done properly. I ended up grounding the rooftop antenna to the home's copper pipe. Copper pipe in a home is normally grounded to the home's electrical panel and "can" provide a clean ground, but I wouldn't just assme that.