This standard was first published in 1966 and revised in 1987. Subsequently, several comments were received and the National Electrical Code was revised in 2011. Also, the Code of practice of Electrical Wiring Installation (IS 732) has been revised in 2018. Therefore, the revision of this standard was undertaken to align with the latest practices. The subject of earthing covers the problems relating to conduction of electricity through earth. The terms earth and earthing have been used in this Code irrespective of reliance being placed on the earth itself as a low impedance return path of the fault current. As a matter of fact, the earth now rarely serves as a part of the return circuit but is being used mainly for fixing the voltage of system neutrals. The earth connection improves service continuity and avoids damage to equipment and danger to human life. Protection against shock, both in normal service (direct contact) and in case of fault (indirect contact) can be achieved by several measures. Details of such protective measures and guidance on their choice are provided in IS 732. Earth fault/leakage protection sought to be achieved through equipotential bonding and automatic disconnection of supply is envisaged to prevent a touch voltage from persisting for such a duration that would be harmful to human beings. Guidance on achieving this protection is covered in this Code.

The object of an earthing system is to provide as nearly as possible a surface under and around a station which shall be at a uniform potential and as nearly zero or absolute earth potential as possible. The purpose of this is to ensure that, in general, all parts of apparatus other than live parts, shall be at earth potential, as well as to ensure that operators and attendants shall be at earth potential at all times. Also by providing such an earth surface of uniform potential under and surrounding the station, there can exist no difference of potential in a short distance big enough to shock or injure an attendant when short-circuits or other abnormal occurrences take place. The recommendations in this Code are made in order that these objects may be carried out. Earthing associated with current-carrying conductor is normally essential to the security of the system and is generally known as system earthing, while earthing of non-current carrying metal work and conductor is essential to the safety of human life, animals and property, and is generally known as equipment earthing. Since the revision of this standard in 1987, considerable experience has been gained through the implementation of its various stipulations. Moreover, several new concepts have been introduced the world over, on the understanding of functional and protective earthing with a view to take into account a variety of complex problems encountered in actual practice. In the context of increased use of electric power and the associated need for safety in the design of installations, it had become necessary to prepare an overall revision of the earlier version of the Code.