Abstract: An incandescent electric lamp and a socket for receipt of the lamp. The socket contains an insulator to prevent completion of the electrical circuit for illuminating the filament contained within the lamp except when the lamp has a wattage rating which is equal to or less than the wattage rating for which the socket is designed. When the wattage rating is proper, the central contact assembly of the base of the electric lamp bypasses the insulator to establish a completed electrical circuit. In one embodiment, the insulator defines an opening of a predetermined diameter through which a protrusion on the base of the lamp extends when its diameter is equal to or less than the opening in the insulator. In an alternative embodiment, the insulator has a diameter of a predetermined value while the central contact assembly defines a depression having a diameter which is equal to or greater than the diameter of the insulator.