How To Size A Cable -

is given by tables (IEC 60287, NEC Table 310.16). For example:

Cable sizing is not merely about matching a conductor to a load current. It is a multi-variable optimization problem that ensures safety, reliability, efficiency, and longevity of an electrical installation. An undersized cable causes overheating, voltage drops, energy losses, and fire hazards. An oversized cable wastes material, increases installation costs, and may create termination difficulties. how to size a cable

$V_d = \frac\sqrt3 \times L \times I \times (R \cos\phi + X \sin\phi)1000$ is given by tables (IEC 60287, NEC Table 310