Self-contained, grounding set tester for portable convenience. This tester provides an easy way for an electric utility to check the resistance in protective grounding sets used by line personnel. Powered by 120 VAC, the tester applies Direct Current across the test specimen. Procedure details are given in the instruction manual. All components store in the tester’s integral carrying case. Simple, one-button testing from pushing a single button, the digital display shows the resistance measured in milliohms compared with a preset threshold for the size grounding cable selected (#2, 1/0, 2/0 or 4/0). For system-specific requirements, the user can easily change the Tester’s basis for voltage allowed across a lineworker, which comes factory preset at 50 Volts.
Adjusting this limit automatically causes a corresponding shift in the resistance thresholds for all the grounding cable sizes. Regardless of the voltage-allowed setting or cable size selected, the Tester displays the resistance of each specimen in milliohms with ±1percentage accuracy, from 1 micro-ohm to 6.5 ohms. The utility must establish the maximum resistance allowed for protective grounding sets used on each specific area of its systems. How the utility calculates these values depends on several factors outlined in the Tester instructions. Sample calculations with reference tables and charts are given in the manual. Troubleshooting mode if a ground set does not pass the initial test, the Tester can help isolate the problems. Often, the source of high resistance can be remedied by simple repairs to the cable set. Retesting then can quickly verify the effects of repairs.