A 2-pole fuse protection of DC connection cables is required for DC low-voltage systems in motor vehicles and on watercraft without a fixed earth or ground reference for safety reasons. For example, there are still some older, English (vintage) car models which, in contrast to the worldwide standard, have the positive pole of the battery connected to earth. In these cases, a short-circuit current could flow completely unprotected, mainly via the negative cable. In this case, positive and negative cables are always fused. The additional fuse in the minus cable prevents the radio from being destroyed, the cable from burning and the battery from blowing up.