How Can We Measure Resistivity Of Earth?
There are different methods for measuring soil resistance. One of the most commonly used methods is the Four Tips Method.
This method involves drilling four holes in the ground, approximately evenly spaced in a straight line.
The diameter of the holes is not more than 10% of the distance between them and they all extend to approximately the same depth, where the greatest resistance is usually concentrated.
Each hole has an electrode that only has electrical contact with the ground near the ground.
It is a four-terminal conductor whose resistance depends on the distance between the electrodes and whose resistivity is found predominantly in a range whose linear dimensions are of the order of the distance between the external electrodes, but in no way significant Value depends on the size of the electrodes or the type of electrical connection they make to the ground.
So if we measure the depth of the holes, the distance between them, and the resistance, we have data from which we can calculate the actual resistance in the area¹.
Another method is the three-point measurement technique, which is derived from the four-point method for measuring soil resistance.
With this method, the ground connection and two other electrically independent measuring electrodes are measured.