For engineers or complex installations, simply using tables is not enough. The earth cable must be calculated to withstand the thermal stress of a fault.
Earth cables are typically identified by their green and yellow insulation. The size you need depends on the cross-sectional area (CSA) of the "line" or "live" conductors in the circuit. 1. Domestic Lighting Circuits (1.0mm² to 1.5mm²) earth cable sizes