56 www.megger.comspecial built-in current clamp that is placed between the C1 connection and the earth. This type of instrument includes noise protection and digitally filters out all currents other than that generated by the instrument. The instrument’s microprocessor automatically performs all the calculations necessary to generate a resistance measurement for the ground electrode.The test is a fall-of-potential test, meaning that all the “rules” still apply. Ideally, the operator would take ten measurements and plot the results to determine true resistance. Proper probe spacing remains critical, and fall-of-potential procedure and methodology must be followed. As with a traditional fall-of-potential test, the results can be proofed by increasing the probe spacings.The advantage of the ART method over traditional fall-of-potential testing is that the ground electrode under test does not have to be disconnected from the system.Using ART method with Megger DET3 Series to test commercial earth (ground)without disconnecting the system
