A system for selectively actuating multiple load devices, such as well tools, which are selectively actuated by applying a predetermined voltage across a predetermined pair of conductors. At least one lockout device is associated with each load device. The lockout device prevents current from flowing through the respective load device until voltage across the pair of the conductors exceeds a predetermined minimum. A method is provided for selecting well tools for actuation by applying a minimum voltage across a set of conductors and a lockout device. Leak paths are prevented from draining off current by the lockout devices. A system is provided for applying current to bidirectional load devices such as downhole pumps and motors.