Abstract: A retrofit switch actuator for a circuit breaker control switch in a power distribution network provides for remote control and automation of the control switch. A solenoid of the switch actuator is energized to move the output shaft of the solenoid. The movement of the solenoid output shaft is converted into rotational motion by an adapter rotatably mounted at one end to the solenoid output shaft and fixedly mounted at the other end to the control shaft of the circuit breaker. The rotational motion of the control shaft mechanically engages the existing circuit breaker control switch.