The FT6380 measures grounding resistance simply by clamping to multiple-grounded ground wires. No auxiliary grounding rod is needed, and there is no need to disconnect the ground wire from the grounding rod. Hioki FT-6380 CLAMP ON EARTH TESTER price is available in sensotech website.
Hioki FT 6380 Features:
Earth resistance measurement for multi-grounded systems
Measure leak current with absolute certainty with highly sensitive 0.01 mA resolution (at 20.00 mA range)
Measure load current up to 60.0 A range
Clamp at the narrowest point