The cable must be thick enough to handle the electrical current (Amps) without overheating.
Before you can determine the cable size, you must determine the load current ($I$). The formula used depends on the power supply type. how to find the cable size formula
The formula used depends on your supply type—Direct Current (DC), Single-Phase AC, or Three-Phase AC. Single-Phase AC: Three-Phase AC: Variables Defined: : Cross-sectional area in mm2m m squared : One-way length of the cable run in meters. : Load current in Amperes. (Kappa): Conductivity of the material ( ΔVcap delta cap V The cable must be thick enough to handle