Every cable has a limit to how much current (Amps) it can handle before the insulation melts.
Keep in mind that these are general guidelines and may vary depending on the specific application and location. working out cable size
While calculations are essential, here are common benchmarks for domestic wiring: Lighting circuits. 2.5mm²: Standard socket outlets (Ring or Radial). 4mm² - 6mm²: Electric showers or cookers. Every cable has a limit to how much