Earth and the Plug

A three-pin plug is designed to connect an appliance safely to the mains supply. The three conductors are: Live Neutral Earth

The live conductor carries the alternating supply potential relative to neutral/earth. It is the conductor that presents the main electric-shock hazard under normal wiring conditions.

Neutral provides the normal return path for current in the supply circuit and is maintained close to earth potential in the distribution system. It should still be treated as part of the electrical system rather than assumed completely harmless.

The earth conductor is a **protective conductor**. It is connected to exposed conductive parts of appliances that require earthing. Under normal operation, it should not carry the appliance's load current.

If a live conductor touches a correctly earthed metal case, the earth conductor provides a low-resistance path. A large fault current can then cause the protective device to disconnect the supply.

Under the widely used IEC colour convention: Live → **Brown Neutral → Blue Earth → Green/Yellow**