Voltage drop formula

The formula for voltage drop depends on the type of the current.

• For DC or 1-phase AC, V = 2 * I * L * R / A / n
• For 3-phase AC, V = √3 * I * L * R / A / n

where:

• V is the voltage drop, measured in volts [V];
• I is the load current, measured in amperes [A];
• L is the one-way length of the wire, measured in meters [m];
• R is the resistivity of the wire, measured in ohm-meters [Ωm];
• A is the cross-sectional area of the wire, measured in square millimeters [mm²];
• n is the number of conductors