
Electrical
Resistivity Testing
Comparable to thermal resistivity, electrical resistivity gauges the capacity of soil to impede the flow of electric current through its volume.
Somewhat similar to thermal resistivity, electrical resistivity determines the resistance to current flow through a volume of soil. The value is expressed in Ohm·m or Ohm·cm.
Electrical resistivity is the most critical factor in the design of grounding grids, taking into consideration the Ground Potential Rise Studies (GPR). Good soil models are the basis of all grounding designs, and they are developed from accurate electrical resistivity testing.
Geotherm performs electrical resistivity tests in accordance with the test method developed by the Electrical Research Department of Ontario Hydro. This is the modified (updated) version of the ‘ASTM G187-12; Standard Test Method for Measurement of Soil Resistivity Using the Two-Electrode Soil Box Method,’ and it allows measurements for a range of density and moisture content.