Intersystem Bonding Termination for Other Utilities
Dear Mr. Electrician: How do I ground my telephone and cable TV demarcation terminal blocks? NOTE: Text links below go to products on Amazon.
Answer: Your telephone and cable TV service each needs to be bonded to a ground rod or water pipe ground, or both if available. This is for lightning protection. If Lightning were to strike the outside cable TV wire and your home has good ground connections, the lightning energy would be channeled directly to earth. With a poor or non-existent earth ground connection, the lightning will find a way to earth, but that could be a path through your TV, computer, major appliance, even the metal ducts in your house. That is how things get damaged or fires start. Click here for photos of one example of a TV and Telephone bonding and grounding on an older house.
The Photo above depicts an Intersystem Bonding Termination which is required by the National Electrical Code. This simple terminal block makes it easy for telephone and cable TV installers to connect their grounding electrode conductor wire to a good earth ground connection. It takes one large grounding electrode conductor and up to four smaller grounding conductors for cable TV and telephone services. It is important to have this for lightning protection. The Intersystem Bonding Termination is required as per article 250.94 in the National Electrical Code. You should also read NFPA 780 on lightning protection.
Something else to consider is the installation of a surge protector. Read my post on that subject here.