Soil Resistivity

Soil resistivity influences the degree of corrosion of buried metals and is also partly
determines the design configurations of cathodic corrosion protection system. Soil
resistivity measurement is normally conducted using Wenner 4-pin Method.
Developed by American National Bureau of Standards, this specifies insertion of four
pins into the ground at even spacing and in a straight line.
The two outer pins are current electrodes and the two inner pins are potential
electrodes, which measure the potential drop due to the resistance of the soil path
when an alternating current is passed between the outer pins. The resistance can be
measured and the resistivity calculated according to the formula, it should be noted
that measurements made in this manner indicate average resistivity over a depth of
soil corresponding to the spacing between adjacent pins.
• Measurement using Wenner 4 Pin Method
• Soil resistance is measured and resistivity is calculated
• Soil resistivity is an indication of how corrosive the local soil conditions above ground survey