How To Ground

A building should have only one ground system. All other grounds should be connected to it. Grounding starts by establishing one low impedance connection to earth. This may be easy to understand, but difficult and expensive to achieve. The quality of the earth ground is dependent on soil conditions. The conditions include: base material, moisture content, presence of salts, and the number, depth, and diameter of the ground rods and their interconnections. A "good ground" can degrade to a "poor ground" due to: draught, freezing, conductive salts being washed away, and corroded connections.

Multiple grounds should be avoided, because they introduce ground-loop currents. Because the earth has variable ground resistance, it is little wonder that different locations have different potentials. These differing potentials produce current loops, which result in unwanted commonmode noise.

Commonly accepted grounds, such as water pipes, should be checked to be sure they do not have PVC connections or feeds. Gas piping should not be used as a ground. Not only is it a violation of the National Electrical Code (NEC), but sparks during maintenance could be a considerable hazard. While conduit should always be connected back to ground, they should not generally be used to ground other equipment.

The connections of the ground cables to the ground rod, and to the panel, should always be checked prior to installing any power conditioning equipment.