Calculation For Cable Size

For 3-phase power (400V/415V), the formula changes slightly because there is no "return" wire in the same way; the voltage vectors are 120 degrees apart. The factor "2" changes to $\sqrt3$ (approx 1.732).

$$A = \frac\sqrt3 \times I \times L \times \rhoV_d$$ calculation for cable size

$$A = \frac20.646.9 \approx 2.99 , mm^2$$ For 3-phase power (400V/415V), the formula changes slightly

Cable sizing is a multi-step process balancing thermal, voltage drop, and short-circuit constraints. Always verify final selection against local regulations and consult manufacturer datasheets. Oversizing for voltage drop or future loads is recommended, especially for long distances or critical circuits. For 3-phase power (400V/415V)