Ground power supply for electric vehicle with earth connection

A ground power supply device for an electrical vehicle having a given footprint (5) including a power supply track (50) made up of segments (52), the segments being separated from each other by insulative joints (54) and each having a length less than half the length of the footprint of the vehicle (5) and a switching device (200) adapted to apply a supply voltage to anyone of the segments (52) only when said anyone of the segments (52) is within the footprint of the vehicle (5) having power supply rubbing member means (80, 81, 82) the extent of which is greater than the length of the insulative joints (54) so that the rubbing means (80, 81, 82) are adapted to contact simultaneously two adjacent segments, and the switching device (200) being adapted to apply the supply voltage to the two adjacent segments (52) which are in simultaneous contact with the rubbing member means and to earth one of those two segments (52) before this segment begins to get out the footprint of the vehicle wherein the device includes, for each segment (52), a controlled component (TH3) adapted to link the segment to earth, and the device includes means (360) to inject a current in the earthing component (TH3), as well as means (RL2, C3, 600) to cut-off the segment (52) relative to a source of said supply voltage, which cut-off means are controlled by the injected current so as to cut-off the segment (52) when the injected current is jammed despite the earthing component being controlled to a jamming state.