A switching selector for selecting a power source from two power sources. It includes a controller, a detection circuit, a transistor and two groups of four transfer switches or relays, wherein the controller is a micro-processor and the detection circuit includes two transformers. Primary winding of each of two transformers is connected to two different power sources, and secondary winding of each of two transformers is connected to input of the controller. Output of the controller is connected to a base of a transistor for controlling the transfer switches. Each group of four transfer switches form a redundant switch for selecting one of the two power sources, where the four transfer switches are connected such that the selection function is not affected when any one of the transfer switches malfunctions.