Abstract: An adapter for mating two or more electrical circuit components to a power distribution box receptacle designed to receive a relay or other circuit component having at least four terminals. The adapter includes a hollow body formed of an electrically non-conductive material, a plurality of contacts disposed within the interior of the body, and means for positioning and frictionally engaging the circuit components so as to retain them within the adapter and with their terminals in electrical connection with the contacts. The contacts are in electrical connection with respective adapter terminals projecting from the adapter body in a configuration substantially identical with the terminals of the circuit component which the adapter replaces, so that the adapter terminals are matable with the receptacle to place the components in connection with circuitry internal to the power distribution box.