AEMC 4620 KIT-300FT [2135.20] 4620 Kit-300ft Ground Resistance Tester. Ground Resistance Tester Model 4620. The Digital Ground Resistance Tester Model 4620 performs earth ground resistance and soil resistivity tests. This direct reading tester measures from 0 to 2000Ω, and is auto-ranging, so it automatically seeks outs the optimum measurement range. The Model 4620 is rugged, easy-to-use and is ideal for maintenance crews performing numerous tests. It exceeds mechanical and safety specifications for shock, vibration and drop tests specified in IEC standards. It is designed to reject high levels of interference, so it can be used under difficult conditions such as high stray currents that normally affect accuracy. The Model 4620 is also available in complete Kits (150ft, 300ft and 500ft).