Question { BSNL, 144542 }
how to check the earth resistance value& what is the
minimum earth resistance for good earthing sysytem.
Answer
As such there is no any standard of earth resistance value,
Its varies on different type of soil resistivity. Idley it
should be 0, but in different kinds of soil for electrical
equipment it should be better to below 10 Ohms and for
electronic equipment it should be better to below 5 ohms.