Soil resistivity data is critical to engineering proper grounding systems for electrical equipment.  ACER utilizes the Schlumberger and the Wenner methods along with proven soil resistivity data collection equipment manufactured by AEMC Instruments.  All soil conducts electrical current; however, its resistivity can vary greatly even throughout small areas.  Soil resistivity is dependent on the characteristics of the soil at a particular site, including type (loam, clay, sand), moisture content, concentration of electrolytes (minerals and dissolved salts), and temperature.  Accurate soil resistivity measurements are necessary to properly design a grounding system capable of adequately conducting electrical charges from electrical equipment.  Proper ground system engineering can increase safety and reduce project costs by ensuring the proposed design will work as planned.