The present disclosure relates to a power supply system (1) including a main unit (10) including a protective main housing (11) and a distribution circuit (20) disposed in the protective main housing (11) and a module unit (30) including a protective module housing (31) and a converter module (40) disposed in the protective module housing (31). A protective connection system (CS) is configured to provide a releasable connection between the module unit (30) and the main unit (10); wherein the protective connection system (CS) includes a first connector device (15), a second connector device (35) and a sealing element (53).