Grounding

[lcaillo]

Grounding

Proper grounding is essential to the protection and proper operation of home electronics. Electrical codes require that all signal lines entering the home, as well as masts for antenna systems (including satellite dishes) must be grounded to the ground rod for the electrical system.

The electrical system ground is often a forgotten part of the protection system. It should be checked for corrosion, loose clamps, and proper connections. Surge protectors need this ground to dump current from surges. If there is resistance in the ground path, surge suppression will be much less effective.

We often see problems with antenna, satellite, and cable installations with respect to grounding. Installers are often not trained in proper installation and often fail to ground the mast and the signal lines to the electrical service ground. Whenever a system is serviced, the technician should be checking for problems or old installations that might have been done before grounding was common practice. This rarely happens with the level of installer training and knowledge found with most companies.

There should be a heavy gauge wire connected from any mast to the electrical service ground point AND from a ground block on EACH signal line at or near the entry point to the home. If not, it MUST be done to assure safety and system protection.

Often, when grounding is not done properly, potentials exist between the points that should be ground on the various systems, resulting in hum, noise, distorted images, and possibly dangerous currents.

More than a few ohms between the grounds on various systems indicates a potential problem. Any leakage current on a ground or exposed conductive surface on a component or wire in excess of 500 micro-amperes is excessive and MUST be corrected.

See this link for more discussion of code requirements:
http://www.mikeholt.com/mojonewsarch...s~20020303.htm

Reference documents for electrical codes:

NEC Section 810-20 re: Antenna discharge unit
NEC Section 810-21 re: Grounding conductors
NEC Article 250 part H re: Service grounding electrode