Electrical cable size calculator
Find the size of a copper cable from its current-carrying capacity and voltage drop, with the circuit breaker, installation method and temperature.
Circuit and protection
1 for a heater or hob, 0.8 to 0.9 for a motor or heat pump.
Automatic: smallest standard rating at or above the design current.
Actual cable route from the board to the appliance, without counting the return.
Usual values: 3% for lighting, 5% for other uses.
Cable and installation
Number of loaded circuits run together (same conduit, trunking or bundle).
Selected size
Minimum copper cross-section