The Digital Ground Resistance Tester Model 4630 performs ground resistance and soil resistivity tests. This direct reading tester measures from 0 to 2000?, and is auto-ranging, so it automatically seeks outs the optimum measurement range. The Model 4630 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 4630 is powered by 9.6V, 3.5 Ah NiMH rechargeable batteries. A built-in recharge circuit, powered from 120/230V 50/60Hz line, also provides for testing while recharging.

The Ground Resistance Tester Model 6417 measures ground rod and grid resistance and impedance without the use of auxiliary rods. Clamp-on ground resistance testers can be used in multi-grounded systems without disconnecting or de-energizing the ground system under test. The Model 6417 simply clamps around the grounding electrode or conductor and measures the resistance to ground. By performing measurements on intact ground systems, the user also verifies the quality of the grounding connections and bonds. Resistance and continuity of grounding loops around pads and buildings may also be measured.