BMW GS 95024-2-1 takes as its subject the vehicle electrical system itself rather than the equipment connected to it, and the three-level numbering suggests that the subject is partitioned by system and sub-system. That focus is significant in modern vehicles, where the electrical system has become a network of several power domains at different voltages, linked by converters and carrying data as well as power, so that a disturbance generated in one part of the installation can reach another part through the converters, the shared earth and the data bus rather than through the supply alone. A requirement written at this level addresses the interaction of the parts, including the transients that appear when a high power load is switched, the behaviour of the network during a start attempt and the coupling between the power and the communication conductors of the same harness. It is applied to the installation rather than to an individual unit.