Wire Voltage Drop Calculator

Voltage drop is the reduction in voltage that occurs along a wire or cable as electrical current flows through it. This happens because:

• All conductors have some electrical resistance
• This resistance causes some electrical energy to be converted to heat
• The longer the wire or the smaller its diameter, the greater the voltage drop

Managing voltage drop is crucial for electrical installations because:

• Excessive voltage drop can cause equipment to malfunction or operate inefficiently
• Most electrical codes specify maximum allowable voltage drop (typically 3-5%)
• Proper wire sizing helps ensure safe and efficient operation
• Reducing voltage drop can improve energy efficiency

The two main conductor materials have different characteristics:

• Copper has lower resistance and better conductivity
• Aluminum is lighter and typically less expensive
• Aluminum requires larger gauge wire for the same current capacity
• Both materials are widely used in electrical installations

DC and AC voltage drop calculations differ in several ways:

• DC calculations consider only resistance
• Single-phase AC includes both conductors in the circuit
• Three-phase AC uses a different multiplier due to phase relationships
• Power factor may affect AC calculations in some cases