Abstract: An electrical receptacle device having a main lamp socket and an auxiliary socket adapted to receive an auxiliary lamp operative only upon failure of a main lamp in a main lamp socket. The two sockets are arranged in aligned opposition in a common housing providing a heating chamber in spaced, parallel relation with respect to the screw base ferrules along one side thereof. A slightly curved, elongated bi-metallic switch element extends along and within the heating chamber, having one end affixed to the main lamp socket ferrule and the other end positioned for movement in and out of contact, selectively, with the auxiliary lamp socket in response to temperature conditions in the heating chamber effected by non-operation and operation, respectively of a main lamp in the main lamp socket.