Earthing & Bonding

Often confused, here’s the difference between earthing and bonding. Both are vital to the safety of your home and need to be checked regularly.



Earthing ensures, in the event of a fault, that the electrical supply is promptly disconnected to prevent electric shock. It does this by providing a path (a protective conductor) for a fault current to flow to earth. For example, a live wire in a cooker may have become exposed by a sharp metal edge. This could make the external casing of the cooker live resulting in serious injury if touched. Earthing ensures that a fault current flows from the exposed wire to the consumer unit promptly disconnecting the electrics and preventing the risk of electric shock.

Bonding & Supplementary Bonding

Bonding is used to reduce the risk of electric shock to anyone who may touch two separate metal parts when there is a fault somewhere in the electricity supply or electrical installation. By connecting the particular metal parts with bonding conductors, bonding reduces the voltage there might have been.

The two types of bonding normally used are main bonding and supplementary bonding. Main bonding is always needed. You may need supplementary bonding for rooms containing a bath or shower, except where all circuits in the room are RCD protected and the main bonding is up to the required standard.