Which grounding system is primarily referenced in the context of fall-of-potential testing?

The three-point ground system is primarily referenced in the context of fall-of-potential testing because it is designed to accurately determine the resistance of grounding systems. This method involves using three electrodes: one is the primary ground electrode being tested, while the other two are used to measure the potential difference and current flow.

In fall-of-potential testing, the primary objective is to assess the resistance between the ground grid and the earth. The three-point method effectively separates the test current from the measuring current, which enhances accuracy and minimizes errors that could arise from nearby grounding systems influencing the results. The configuration also allows the operator to establish a clear baseline for measurements, which is essential for ensuring that the grounding complies with local electrical codes and standards.

Other grounding system configurations, like two-point, four-point, and single-point systems, do not provide the same level of reliability and accuracy in measuring ground resistance as the three-point system does. For example, the two-point system lacks the necessary third electrode to effectively measure the fall-off potential and can yield inaccurate results due to potential influencing factors.