Table

Voltage Drop Sensitivity by Current and Distance

Voltage Drop Sensitivity by Current and Distance reference with assumptions and boundary notes.

Reference boundary

Relationship reference only. It does not determine whether a circuit result is acceptable.

Reference table

See how voltage drop changes when current, distance, voltage, or conductor resistance changes.

Formula basis follows voltage drop being proportional to current, one-way distance, and conductor resistance.
ChangeVoltage-drop effectWhyExample
Current doublesVolts dropped doublesCurrent is a direct multiplier20 A to 40 A doubles the estimated drop
One-way distance doublesVolts dropped doublesLength is a direct multiplier30 m to 60 m doubles conductor resistance in the path
Conductor area doublesVolts dropped is roughly halvedResistance is inversely related to areaLarger conductors reduce resistance
Nominal voltage doublesPercent drop is roughly halvedSame volt drop divided by higher voltage6 V drop is 5 percent at 120 V and 2.5 percent at 240 V
Use notes
  • Use this table for preliminary reference and arithmetic checks only.
  • Confirm equipment ratings, product markings, installation conditions, utility requirements, and the local authority requirements before design or field use.