A Comparison of Concrete Encased Grounding Electrodes to Driven Ground Rods

An experimental study was made to compare the efficacy of concrete encased grounding electrodes to that of driven ground rods for grounding residential and small commercial electric services. This study extended over 14 months and included a very wet winter and a dry summer. The ground resistances of both grounding systems were monitored for the first 5 months. Current from an isolated 120/240-volt system was then circulated through both grounding systems for the following 6 months. At the end of the 14-month period, fault current from power systems of 2.4 to 20 kV were applied to both grounding systems. The ground resistance variations were recorded in all cases.