Earth cable size can be determined using Table 5.1 in AS/NZS 3000 or by calculation.
Table 5.1 works by specifying a minimum earth cable size based on the active conductor size and the material. The method below is conservative and often over-sizes the earth cable.
Cable Pro Web.
Cable Pro Web software calculates earth cable size based on fault loop impedance and short-circuit performance. This often results in smaller earth cable sizes.
Please enter the parameters below and press Calculate.