DoElect

Methods of Earthing In theory, the main power network does not have to be earthed and sometimes arguments are put forward that an unearthed network may be more reliable. In some cases this can be true, but generally an unearthed networks can be unreliable due to influence of electrical or some other factors. There are a number of ways in which an electrical power system can be operated – - Unearthed or insulated system - High impedance earthed and - Low impedance earthed arrangement Unearthed system/IT earthing system In this kind of installation, there is no formal connection to earth because there may be some high impedance connections for instrumentation e.g coil of a measuring device. Earthed vs Unearthed Electrical cable In some generators and transformers, the star point is solidly grounded. This is called Earthed Electrical system. In a three phase earthed system, phase to earth is 1.732(sqrt 3) is solidly earthed system higher than phase to phas...