A method is applied depending on the size of the grounding system. The dispersion resistances of conductor rods can be measured with the above-mentioned special ground resistance measurement devices.
Grounding measurement device: This device is used for a single deep grounding rods, strip grounding rods, grounding rods of overhead line poles whose grounding wires are lifted (disconnected from the pole) or not lifted, in small or medium-sized grounding systems, and for grounding installations in medium voltage networks separated from AG grounding installations. The frequency of the used alternative voltage should not exceed 150Hz.
The grounding rod to be measured, the probe, and auxiliary grounding rods must be as far as possible from each other, and on a straight line. The distance between the grounding rod to be measured and probe must be at least 20m, and 2.5 times the length of the largest grounding rod (towards measurement direction); and the distance of the auxiliary grounding rod must be at least 40m, and four times the length of the largest grounding rod.