Abstract: The invention relates to a method and a device for determining a maximum leakage current in unearthed power supply networks with a plurality of conductors. The method comprises the steps of: feeding of a measurement signal UP with a measurement frequency fPuls into a conductor arrangement, setting the measurement frequency fPuls, measuring a line-to-line voltage UL-E for each conductor, determining a maximum occurring line-to-line voltage UL-Emax from the measured line-to-line voltages UL-E, determining a voltage UZe across a measurement resistance RM for calculating a leakage impedance ZE, calculating the leakage impedance ZE, and calculating a maximum leakage current THC. The device comprises a signal generator for feeding in the UP with the fPuls, a network coupling circuit between the signal generator and the conductor arrangement, a voltage measuring circuit for measuring the UL-E, and an impedance measuring circuit for determining the Ze by means of the determining of the UZe.

Abstract: The invention relates to a power charging device (10) for an electric vehicle (12) with an electric energy store (14). The power charging device (10) comprises at least one rectifier means (16) for converting a supply voltage (18) into a charging d.c. voltage (20), a contacting means (22) for contacting a plug-in connection supply point (24) of the electric vehicle (12), and a residual current monitoring device (26) for detecting a current difference in the contacting means (22) and/or the electric vehicle (12) during a charging process of the energy store (14) of the electric vehicle (12). The invention is characterised in that the residual current monitoring device (26) is designed at least for detection of a direct current difference ?I and comprises a cutoff element (28) which can interrupt the charging process when a predeterminable direct current cutoff difference (36) is exceeded over a predeterminable cutoff time.