![]() You must bond all system grounds, antenna, power, CATV, telephone, and so on with a heavy bonding jumper. This symmetry cancels, to first order, all effects of external electromagnetic fields. Coaxial cables have fairly good natural immunity to external noise, due to the physical symmetry of the signal current conductor and the returning current conductor (the concentric shield). Omitting this jumper is a serious Code violation, second only to no grounding at all. 10.2.2 Coax: Radio Frequency Interference. However, even after this dedicated grounding means is established, in order to be NEC-compliant, the installation must have a bonding jumper not smaller than 6 AWG or equivalent, which is connected between the CATV system's grounding electrode and the power grounding electrode system for the building. The major distinguishing characteristic is that for one- and two-family homes the grounding conductor cannot exceed 20 feet in length and should preferably be shorter. If a grounding electrode such as the Intersystem Bonding Termination is not within 20 feet, it is necessary to drive a ground rod for that purpose. The grounding conductor is 14 AWG minimum so that it has current-carrying capacity approximately equal to the outer shield of the coaxial cable. The grounding conductor is 14 AWG minimum so that it has current-carrying capacity approximately equal to the outer shield of the coaxial cable. Instead, the shield of the coaxial cable is connected to an insulated grounding conductor that is limited to copper but may be stranded or solid. There is no antenna discharge unit as required for satellite dish installation. Improper grounding of coaxial cable used for CATV is very common. Because of the spacer, capacitive coupling is diminished so that the cable provides a high-quality signal for data, voice, and video transmission. Typically, CATV is brought into the building via coaxial cable, which has a center conductor, insulating spacer, and outer electrical shield. Grounding for CATV is slightly different. If the CATV coax cable shield is properly grounded then I would look for a loose and or corroded connection of the ground wire that bonds, connects, the ground block to the grounding system of your house. Also connected to the ground block is a wire that should connect to the main grounding system of the electrical service of the house. From the grounding block another coax cable is connected and enters your home. Since your problem is verifiably caused by the coax input to the TV, the ground loop isolator you have referenced is the better resolution, although at USD 17.99, its about twice the typical price. If you look outside your house where the provider's CATV coax cable attaches to the house and follow the coax cable to where it enters the house you should see a grounding block where the coax cable connects to. For lightning protection NEC safety code require the CATV provider's RG6 coax cable's outer shield be bonded, connected, to the main grounding system of the electrical service of your home. I would suggest you find the cause of the ground loop. The lightning would just flash over the isolator device. ![]() Click to expand.Though the ground loop isolator stops the hum it will not protect your A/V equipment from a near by lightning strike.
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