A power switch comprises a SPDT switch having a common side and a switch side; a first isolation switch electrically connected at the common side of the SPDT switch and a second isolation switch electrically connected at the switch side of the SPDT switch; a microprocessor for detecting a current direction and controlling the conduction state of one of the first isolation switch and the second isolation switch in response to the detected current direction; and a power converter converting AC power to DC power for powering the first isolation switch, the second isolation switch and the microprocessor.