A fastening device for a cable is operatively connected to a motor vehicle. The fastening device includes a holder fixedly secured to the motor vehicle. The holder defines a receiving opening with a stop extending out along a side of the receiving opening. A cable feedthrough grommet surrounds a portion of the cable in a cable longitudinal direction. The cable feedthrough grommet includes a radial thickening and defines a groove extending through the radial thickening. The groove is received by the receiving opening of the holder to hold the cable feedthrough grommet in place. The cable feedthrough grommet includes a protuberance that extends radially out from the radial thickening to engage the stop of the holder to prevent the cable feedthrough grommet from being secured to the holder in a misaligned manner.