Abstract: An assembly of an electrical device includes: at least one electrical functional assembly which has a supporting element and electrical or electronic functional components arranged on the supporting element; a fastening device for fastening the electrical device to a higher-level assembly; a heat sink core element having at least one face wall; and an external element connectable to the heat sink core element. The heat sink core element forms a supporting structure of the electrical device on which supporting structure the fastening device is arranged. The external element is connectable to the heat sink core element such that the at least one electrical functional assembly is accommodated between the at least one face wall of the heat sink core element and the external element.