Abstract: A receptacle includes an insulated outer case, first and second trip switches formed on an inner bottom of the insulated case, a reset switch formed on the inner bottom of the insulated outer case, a cover disposed on a top of the outer case, first and second test buttons disposed in the insulated outer case to be movable in a vertical direction, each of the first and second test buttons having a bottom adjacent to the corresponding trip switch and a top exposed through the cover, a first spring for biasing the first and second test buttons to an initial position, a reset button disposed in the insulated outer case to be movable in a vertical direction, the reset button having a bottom adjacent to the reset switch and a top exposed through the cover, and a locking portion for selectively locking the reset button in response to the vertical motion of the first and second test button.