Pci ltd provides digital and portable earth resistance testers [model metrohm e1610]. These are specially manufactured to measure earth/ground resistance, earth/ground continuity and soil resistivity. Four terminal measurement methods are used for testing. The loading of the earth/ground resistance can be prevented by ignoring resistance of the potential circuit test. The large display can show the earth/ground resistance. For electric supply and wiring safety it is necessary to install satisfactory earth/ground systems. In many communication systems it is also necessary. Earthing/ground system should be tested regularly after the installation. These testers are essential for testing large earthing/ground systems where very low resistance is required. High levels of interfering stray voltages, high ground currents or high value auxiliary plate resistance do not affect the system.
