A plug includes a first member and a second member detachably connected to each other. The first member includes four conductors, which are separated from each other. The third and fourth conductors are selectively electrically connected to the first and second conductors, respectively. The second member includes four pins. The first and second pins are electrically connected to the first and second conductors, respectively, and are selectively electrically connected to the third and fourth conductors, respectively. The third and fourth pins are electrically connected to the first and second pins, respectively. The first and second pins are separated from each other, and the third and fourth pins are separated from each other. A power supply configured with the plug and a power connector are also provided.