It is inter alia disclosed to an apparatus (100), comprising an interface (110) configured to be connected to a cable, the interface (110) comprising a first terminal (111) configured to be connected to a first line of the cable, a second terminal (112) configured to be connected to a second line of the cable, and a third terminal (113) configured to be connected to a shield line of the cable, and comprising a charger (120) configured to provide a voltage between the first terminal (111) and the second terminal (112), wherein said voltage is based on a predefined voltage and a compensation voltage, the compensation voltage being dependent on a voltage between the third terminal (113) and the second terminal (112).