Earth wires conduct electricity from a faulty light through the wire to the earth rather than electrocuting you. In Australia, some lights require an earth wire, and others don’t. For wall lights that are made from non-conductive materials such as plastic, glass or ceramic, an earth connection is not required, as the risk of electrocution is low. Wall lights with a metal exterior must be earthed, as the material conducts electricity, to prevent any accidents from occuring.