A safety cover for a socket or switch has a frame arranged to extend on three sides of a rectangular faceplate of the socket or switch and a cover panel hinged to the frame for pivotal movement towards and away from a position in which the cover panel conceals the faceplate. The frame is of U-shape and defines an opening in which the faceplate is received. The frame has inwardly directed lips contiguous with a rear face of the frame that locate behind the faceplate on opposite sides of the opening clear of the fixing screws used to secure the faceplate to a mounting box. The safety cover can be fitted by partially releasing the screws and sliding the lips under the faceplate as the frame is positioned around the faceplate and then tightening the screws to secure the faceplate and hold the frame in place by securing the lips under the faceplate.