IEC – Running Voltage Drop Calculation

The IEC standard specifies the equation for voltage drop calculation as follows:

Vd = Ph * Id ( [(R * L * cosø) / A] + [X * L * sinø] )

Where:

V d = actual voltage drop, in volts

Ph is the coefficient equal to 1 for three-phase circuits, 2 for single-phase (phase to phase) and equal to 2 for single-phase (phase to neutral)

R is the Resistivity of conductors in normal service, taken to be equal to the Resistivity at the normal service temperature, i.e. 1.25 times the Resistivity at 20 °C, or 0.0225 Wmm2/m for copper and 0.036 Wmm2/m for aluminium

L = route length of circuit, in metres

A = cross-sectional area of conductors, in mm2

cosø is the power factor

X is the reactance per unit length of conductors, which is taken to be 0.00008 W/m in the absence of other details

Id = the current to be carried by the cable, in amperes.

Note:
In case of cables in parallel this is the design current divided by 2.

The result of this calculation can be found in Sizing Result tab as shown below.