An electrical module arrangement for supplying electrical power to a printed circuit board mounted within the housing of an electrical module, including a plug-in electrical connector mounted in an opening contained in an end wall of the module housing. The connector is of the conductive leaf spring S-shaped type, including two reversely-bent portions defining oppositely directed recesses for receiving a bus bar voltage source and a planar contact of the printed circuit board, respectively. In a modification, the leaf spring is W-shaped including three bends, thereby permitting connection of the PCB contact with two separate parallel spaced bus bar arrangements. A plurality of the modules are supported in side-by-side relation either by mounting the module housings on a common mounting rail, or by connecting the plug-in connectors to a common bus bar mounted on a fixed support.