Resistance of the earth is generally very low and the equipment of power systems are connected to the earth with the help of earth electrode. Earth prevents any kind of faults while the flow of current. However, before installing a power system, it becomes necessary to check the earth resistance. For this task, an earth tester is required by the electricians.
Organizations make use of these devices for ensuring safe installations of power systems because generally the systems used there are many and bigger. At home also, the safety needs to be ensured in the same way, no matter the power equipment takes small space.