The invention relates to an electrical vehicle charging system, including a power source configured for providing electrical energy to charge an electrical vehicle, an outlet port configured for connecting the electrical vehicle to the charging system and for providing a DC voltage to the electrical vehicle, a switch configured for connecting the outlet port and the power source, and a control device configured, if the electrical vehicle is unconnected to the outlet port, for measuring the DC voltage at the outlet port, and configured, if the measured DC voltage is greater than zero, for switching off the DC voltage.