The first earth tester was invented in the year 1950 by Evershed and Vignoles Meggers who made the initial insulation as well as earth resistance testers. Analog grounding tester like М416 is the most frequently used in the USSR. Many organizations from the 21st century manufacture digital earth resistance meters as well as testers. The main function of this instrument is to decide the capability of the grounding for an electrical system. By a NEC … [Read more...]