Calculate resistance, current density and heating for a conductor at a given load.
Loss rises with the square of current, so a conductor at twice the current dissipates four times the heat. Current density around 3 to 5 A/mm² is typical for insulated copper in free air. Because loss scales with I², going one cable size larger often pays for itself in reduced energy loss over the installation’s life.
Conductor Resistance
R = ρ L ÷ A; loss = I² R; current density = I ÷ A
R = ρ L ÷ A; loss = I² R; current density = I ÷ A Loss rises with the square of current, so a conductor at twice the current dissipates four times the heat. Current density around 3 to 5 A/mm² is typical for insulated copper in free air.
Because loss scales with I², going one cable size larger often pays for itself in reduced energy loss over the installation’s life.
This calculator takes 4 inputs: Conductor cross-sectional area, Conductor length, Current carried, Conductor material. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.