Sewer inspection and/or maintenance system comprising an electrical interface, wherein the sewer inspection and/or maintenance system has - a sewer inspection and/or maintenance unit, and - an external unit that can be electrically coupled to the sewer inspection and/or maintenance unit, wherein - the sewer inspection and/or maintenance unit has a housing that is designed to be fluid-tight and/or gas-tight, - the housing has a first electrically conductive portion and at least one second electrically conductive portion, wherein the electrically conductive portions (11a; 11b) are electrically insulated from one another by means of an insulating layer, - the external unit has a first electrical contact and at least one second electrical contact, wherein the electrically conductive portions (11a; 11b) and the electrical contacts (22a; 22b) are designed such that the first electrical contact can be brought into electrical contact with the first electrically conductive portion, and the at least one second electrical contact can be brought into electrical contact with the at least one second electrically conductive portion, wherein the housing and the external unit are designed such that they can be coupled to one another in a positive and/or non-positive manner, wherein the housing has a recess having two walls, in which the external unit can be at least partially received in a positive and/or non-positive manner, wherein the two walls are electrically insulated from one another and are each part of the electrically conductive portions (11a; 11b) of the housing, wherein the external unit has movable coupling elements that, when the external unit is coupled to the housing, move into wall-side coupling recesses of the housing which correspond to said coupling elements in order to secure the external unit in the recess, wherein the coupling elements are the electrical contacts (22a; 22b), wherein the electrical contacts (22a; 22b) are each arranged in a radial blind hole of the external unit, and wherein the electrical contacts (22a; 22b) are at least partially pressed out of the relevant blind hole when the external unit is coupled. - a sewer inspection and/or maintenance unit, and - an external unit that can be electrically coupled to the sewer inspection and/or maintenance unit, - the sewer inspection and/or maintenance unit has a housing that is designed to be fluid-tight and/or gas-tight, - the housing has a first electrically conductive portion and at least one second electrically conductive portion, wherein the electrically conductive portions (11a; 11b) are electrically insulated from one another by means of an insulating layer, - the external unit has a first electrical contact and at least one second electrical contact, wherein the electrically conductive portions (11a; 11b) and the electrical contacts (22a; 22b) are designed such that the first electrical contact can be brought into electrical contact with the first electrically conductive portion, and the at least one second electrical contact can be brought into electrical contact with the at least one second electrically conductive portion, wherein the housing and the external unit are designed such that they can be coupled to one another in a positive and/or non-positive manner, wherein the housing has a recess having two walls, in which the external unit can be at least partially received in a positive and/or non-positive manner, wherein the two walls are electrically insulated from one another and are each part of the electrically conductive portions (11a; 11b) of the housing, wherein the external unit has movable coupling elements that, when the external unit is coupled to the housing, move into wall-side coupling recesses of the housing which correspond to said coupling elements in order to secure the external unit in the recess, wherein the coupling elements are the electrical contacts (22a; 22b), wherein the electrical contacts (22a; 22b) are each arranged in a radial blind hole of the external unit, and wherein the electrical contacts (22a; 22b) are at least partially pressed out of the relevant blind hole when the external unit is coupled.