Electric Cable Size Calculator ((top)) Jun 2026

A: Copper is the standard for residential wiring due to its superior conductivity and flexibility. Aluminum is typically reserved for large service entrance cables or overhead lines due to cost, but it requires special handling and anti-oxidant pastes.

Electricity loses energy as it travels through a conductor, a phenomenon known as voltage drop. The longer the cable, the higher the resistance, and the more the voltage "sags" by the time it reaches the device. Most electrical codes recommend keeping voltage drop under 3% for lighting and power circuits. If you are running power to a detached garage 100 feet away, a cable size calculator will often suggest a thicker gauge than a short 10-foot run would require to compensate for this loss. Installation Environment and Derating Factors electric cable size calculator

To get an accurate result, you need four specific pieces of information: The System Voltage (e.g., 120V, 240V, or 480V). The Total Load in Amps or Watts. The Length of the run (meters or feet). A: Copper is the standard for residential wiring

The system voltage (e.g., 120V, 230V, 240V, 480V) affects the calculation, particularly regarding voltage drop over long distances. The longer the cable, the higher the resistance,

This is where most DIYers fail. Voltage drop is a silent killer.