Switch-off Device, High-Voltage Onboard Electrical System, and Motor Vehicle

A switch-off device includes a current conductor for forming a load current path, a pyrotechnically activatable separating unit for interrupting the load current path in the event of a fault, including a separating element for detaching the current conductor and a pyrotechnic element for accelerating the separating element in the direction of the current conductor, and an arc extinguishing unit for extinguishing an arc, including a melting conductor which is not normally incorporated into the load current path and an extinguishing device for extinguishing the melting conductor.