Voltage drop, 3-phase AC

cable cross-section:
[mm 2 ]
length of the cable from a source to the consumer:
maximum current:
[A] or power [W]
rated voltage:
cos( φ):
calculated voltage drop:
_ [%]

The voltage drop is calculated in accordance with the following equation:

3AC_voltage_drop, where:

  • In, rated current [A],
  • l, length of cable [m],
  • σ, conductivity, for copper 58 [S*m / mm 2 ],
  • Un, rated voltage [V],
  • s, cable cross-section [mm 2 ],

Voltage drop on cables between generators and main switchboard is not to be more than 1%

Voltage drop is not to exceed:

  • 10% for lighting and signalling devices,
  • 10% for power consumers at short-time and intermittent service,
  • 7% for power and heating consumers,
  • 5% for navigation light circuits,

Author: Daniel Czarkowski