The invention relates to a sensor module (10) for measuring an electrical variable, comprising at least one electrode (12, 13), which is arranged in a housing (58) made of an electrically insulating material and which can be connected to an electrical measuring device by means of a connecting cable, wherein the electrode has a sensor element, which is arranged between an inner and an outer contact plate (26,27) made of a carbon material and which is coupled to the connecting cable, wherein an outer contact plate (27) of the electrode is arranged in an outer face of the housing.