Motor vehicle on-board power supply system comprising - a battery, - a plurality of consumers, - a primary fuse, - a plurality of paths via which the primary fuse, which is electrically coupled to the battery, is electrically coupled in series with each one of the consumers, wherein each path comprises at least one of a plurality of secondary fuses, wherein the primary fuse and the secondary fuses are designed as reversible fuses and a control device of the motor vehicle on-board power supply system is configured to access said fuses to determine whether a fault has arisen in the motor vehicle on-board power supply system, said fault satisfying a triggering criterion at least for one of the fuses comprised by at least two of the paths, and, in this case, to selectively actuate the fuses in such a way that the fault-free paths are identified and the fuses in the fault-free paths are subsequently switched on again, characterized in that - the secondary fuses are arranged in a plurality of fuse layers (10, 10'), which each comprise a plurality of parallel-connected secondary fuses, in such a way that individual secondary fuses in one of the fuse layers are electrically coupled in series with a plurality of secondary fuses of another fuse layer and are therefore comprised by a plurality of the paths, and - the control device is configured, for the purpose of identifying the fault-free paths, to individually check only the paths having the at least one fuse for which the triggering criterion is satisfied in a prescribed order and: • to subsequently switch on the fuses of all the fault-free paths identified in the process again, or • as soon as a path having the at least one fuse for which the triggering criterion is satisfied has been identified, to switch on the fuses of all the other paths. - a battery, - a plurality of consumers, - a primary fuse, - a plurality of paths via which the primary fuse, which is electrically coupled to the battery, is electrically coupled in series with each one of the consumers, wherein each path comprises at least one of a plurality of secondary fuses, wherein the primary fuse and the secondary fuses are designed as reversible fuses and a control device of the motor vehicle on-board power supply system is configured to access said fuses to determine whether a fault has arisen in the motor vehicle on-board power supply system, said fault satisfying a triggering criterion at least for one of the fuses comprised by at least two of the paths, and, in this case, to selectively actuate the fuses in such a way that the fault-free paths are identified and the fuses in the fault-free paths are subsequently switched on again, characterized in that - the secondary fuses are arranged in a plurality of fuse layers (10, 10'), which each comprise a plurality of parallel-connected secondary fuses, in such a way that individual secondary fuses in one of the fuse layers are electrically coupled in series with a plurality of secondary fuses of another fuse layer and are therefore comprised by a plurality of the paths, and - the control device is configured, for the purpose of identifying the fault-free paths, to individually check only the paths having the at least one fuse for which the triggering criterion is satisfied in a prescribed order and: • to subsequently switch on the fuses of all the fault-free paths identified in the process again, or • as soon as a path having the at least one fuse for which the triggering criterion is satisfied has been identified, to switch on the fuses of all the other paths. • to subsequently switch on the fuses of all the fault-free paths identified in the process again, or • as soon as a path having the at least one fuse for which the triggering criterion is satisfied has been identified, to switch on the fuses of all the other paths.