An interruption device is provided in a motor vehicle to interrupt a signal line in an emergency operating state. The interruption device includes a fuse and a resistor in the signal line and first and second switches. The fuse is arranged upstream of the resistor in a signal line direction extending from a low-voltage on-board electrical system to a high-voltage on-board electrical system. The first switch is provided in a first electric line connecting the signal line to ground at a connection point downstream of the resistor, and the second switch is provided in a second electric line which connects the signal line to ground at a connection point between the fuse and the resistor. The first and second switches are open during the normal operation of the motor vehicle and are closed in response to the control signal to interrupt the signal line by separating the fuse.