Sparky

Voltage Drop

Cable voltage drop from an AS/NZS 3008 mV/A/m figure.

Current(A)

Route length (one way)(m)

Cable mV/A/m(mV/A/m)

From AS/NZS 3008 for the cable size, type and phase.

Nominal voltage(V)

Voltage drop

4.44 V

Percent drop1.93 %

Voltage at load225.6 V

Formula

Vd = (mV/A/m x current x length) / 1000

(7.4 x 20 x 30) / 1000 = 4.44 V

Guide only. Take mV/A/m from AS/NZS 3008 for the cable, and keep total drop within the AS/NZS 3000 limit (commonly 5% from the point of supply).