Voltage Drop Calculator

voltage drop calculator calculates how much voltage is lost along an electrical cable for both single-phase and three-phase systems, helping determine if the voltage drop is within acceptable limits.

Circuit Parameters

A
m
V

Conductor Size

Results

Single-phase:
Voltage Drop: 0 V
Voltage Drop: 0%
Three-phase:
Voltage Drop: 0 V
Voltage Drop: 0%

Formula Reference

Single-phase System

\[ \Delta U = \frac{2 \times l \times I \times \rho \times \cos \phi}{A} \]

\[ \Delta U\% = \frac{\Delta U \times 100}{U} \]

Three-phase System

\[ \Delta U = \frac{\sqrt{3} \times I \times l \times \rho \times \cos \phi}{A} \]
\[ \Delta U\% = \frac{\Delta U \times 100}{U} \]

Unit Descriptions

\(\Delta U\) - Voltage drop (V, Volts)
\(\Delta U\%\) - Voltage drop percentage (%)
\(I\) - Current (A, Amperes)
\(l\) - Cable length (m, meters)
\(\rho\) - Resistivity of conductor material (Ω⋅mm²/m, Ohm square millimeter per meter)
  • Copper: 0.0175 Ω⋅mm²/m at 20°C
  • Aluminum: 0.028 Ω⋅mm²/m at 20°C
\(\cos \phi\) - Power factor (dimensionless, between 0 and 1)
\(A\) - Cross-sectional area of conductor (mm², square millimeters)
\(U\) - Nominal voltage (V, Volts)