What type of wire is used?
Wiring varies with each installation, but standard wire is generally routed from the power supply (grid, generator, solar), through a service panel/circuit breakers, through control switching devices (pressure switch, liquid level control, etc.) to the control box. From there, special submersible wire is used to carry the electricity down the well, and through the water to the submersible motor. The wire size depends on the total distance from the power supply to the submersible, not just the distance from the surface on down.
