Known ground fault protection (GFP) technologies commonly rely on electrically-conductive elements (i.e., electrodes) driven, augered, or buried a significant depth into the ground in order to effectively conduct electrical current into the ground. Such conductive elements, commonly known as earth rods or ground rods, are driven or augered at least 8 feet into the ground to ensure that desired functional effectiveness is achieved. Alternative known GFP technologies use conductive elements in the form of ground mats that conduct electrical current to the ground by contacting the ground over a substantial interface area, with minimal if any ground penetration.
An ideal grounding connection maintains zero voltage regardless of how much electrical current flows into or out of the ground. The electrical resistance of the electrode-to-earth connection determines the quality or effectiveness of the grounding connection. The quality of a grounding connection may be improved in a number of ways, for example: by increasing the electrode surface area in contact with the earth; increasing the depth to which the ground rod is driven or augered (in cases where the electrode is a driven or augered ground rod); using multiple connected electrodes; increasing the moisture content of the soil; improving the conductive mineral content of the soil; and/or increasing the ground surface area covered by the grounding system.
The installation of driven or augered earth rods typically entails the use of specialized rod-driving or augering equipment, and even with the use of such equipment earth rod installation can be difficult due to soil conditions (for example, rock formations close to surface). Even when soil conditions are readily conducive to earth rod installation, the presence of buried utilities (e.g., gas lines, electrical power lines, water lines) can give rise to the risk of personal injury and expensive utility repair costs should such buried utilities be contacted or penetrated by earth rods during the rod installation process. These latter risks can be mitigated or avoided by the use of ground mats not having ground-penetrating elements, but such devices may have less than desired or optimal functional effectiveness.
For the foregoing reasons, there is a need for improved electrical ground fault protection devices that provide effective grounding with minimal penetration of conductive elements into the ground.
USPTO Backgrounds
USPTO Backgrounds