Soil Resistivity is most necessary when determining the design of the grounding system for new installations (green field applications) to meet your ground resistance requirements. Ideally, you would find a location with the lowest possible resistance. The resistance of an earth electrode is related to the resistivity of the soil in which it is placed and driven, and thus soil resistivity calculations and measurements is a crucial aspect when designing earthing installations.
Measurements of earth resistivity are useful also for finding the best location and depth for low resistance electrodes. Such studies are made, for example, when a new electrical unit is being constructed; a generating station, substation, transmission tower, or telephone central office.
