How To Do Electrical Grounding System Testing

The amount of amperage running through the tested system must be below the equipment manufacturer’s limits. The test signal must be injected at the proper location, so that the signal is forced through the grounding system and into the earth. This instrument actually measures the sum of the resistance of the grounding system under test and the impedance of the utility neutral grounding, including the neutral wiring. Due to the high frequency used, the impedance of the neutral wiring is non-negligible and can be greater than the ground resistance of a very low resistance grounding system, which can therefore not be measured accurately. The ground resistance of a large grounding system at 60 Hz can be significantly lower than at 1.7 kHz.