Check how much voltage is lost along a cable run before it reaches the load, in volts and as a percentage.
Tell us what you need to power and we will confirm the exact model, voltage and configuration — usually within 24 hours.
Every conductor has resistance, so the voltage at the far end of a cable is always lower than at the source. Current, cable length and conductor size all increase the loss. Above roughly 5% the consequences stop being theoretical: motors run hot and lose torque, contactors chatter, and electronic controls reset themselves.
Single-phase: Vd = 2 × L × I × ρ ÷ A. Three-phase: Vd = √3 × L × I × ρ ÷ A.
Most wiring regulations set 3% as a design target for final circuits and 5% as a maximum from the origin of the installation to the furthest point. Beyond 5% motors and electronics start to misbehave.
Because ampacity and voltage drop are two separate checks. A cable can be thermally safe and still lose too much voltage over a long run. Always verify both.
No. It is a design aid that uses the standard resistive formula. Final cable selection must also account for installation method, ambient temperature, grouping and local regulations.
