Australian standards require that the cable's rated current (Iz) must be greater than or equal to the circuit's designed load current (In). For a standard 10-amp general power outlet (GPO), a 1.5 mm² copper cable is the minimum. For a 32-amp oven or cooktop, 4.0 mm² or 6.0 mm² is typical.
The primary document governing cable selection in Australia is the Australian/New Zealand Standard for Wiring Rules (AS/NZS 3000). This mandatory standard provides the tables and methodologies electricians must use. Unlike some countries that rely on "rule of thumb," Australia mandates a rigorous calculation process. The standard works in conjunction with AS/NZS 3008.1.1, which provides the specific current-carrying capacity tables for cables. Compliance with these standards is legally required under the National Construction Code (NCC) and various state electrical safety acts. electrical cable size australia
To combat voltage drop, the cable size must be increased. While a 1.5 mm² cable might handle the current of a 5-amp light over 10 metres, that same cable over 100 metres would fail the voltage drop calculation. Thus, for rural properties or large commercial floors, voltage drop—not current—often dictates the final cable size. Australian standards require that the cable's rated current