When performing a 3-pole fall of potential ground test, what is the minimum distance the probe stake should be from the earth ground electrode?

In a 3-pole fall of potential ground test, the minimum distance the probe stake should be from the earth ground electrode is critical for obtaining accurate measurements. The purpose of the test is to determine the resistance of the grounding system while ensuring that the measurement does not get influenced by nearby ground electrodes or other conductive paths.

The reason why 64 feet is the correct distance is based on the principle that it should be far enough away to ensure that the influence of the grounding electrode does not distort the readings. If the probe stake is too close to the electrode, the test can result in erroneous readings, as the potential does not drop sufficiently away from the immediate vicinity of the ground electrode. At 64 feet, the probe stake is positioned in a location where the potential difference can be accurately measured without significant interference from the ground electrode itself.

The other distances provided, while they might seem plausible, do not align with the established best practices for this particular testing method. A distance too short could lead to non-representative readings, while a distance much longer may not necessarily enhance the accuracy beyond what is required for effective measurement within the context of the fall of potential testing.