Earthing and Bonding
The principal reasons for earthing and bonding in electrical installations are:
- To eliminate the possibility of electric shock to personnel;
- To enable protection devices to operate correctly so that the duration of fault currents are kept to a minimum;
- To equalise the voltage potential of normally non-current carrying metalwork;
- To prevent electrostatic charge of process plant due to fluid movement.
In hazardous areas, the elimination of sources of ignition is very important and effective earthing and bonding will play an important role here. Electrical faults, if allowed to persist, can develop to a point where excessive surface temperatures and/or arcs/sparks are produced.
IEC 60079-17 clause 4.7 states: ‘Care shall be taken to ensure that the earthing and potential equalisation bonding provisions in hazardous areas are maintained in good condition’.