A-C and D-C short-circuit tests on aircraft cable

Higher-voltage d-c and 400-cycle a-c electric systems are being developed for large aircraft with increased electrical load order to obtain lower conductor weights than would be required with the present 28.5-volt system. In view of the apparent freedom from sustained faults in low-voltage a-c systems despite damage from gunfire, the use of protective devices to isolate aulted cables has been considered unnecesary. The need for protective devices on the higher-voltage systems will depend on the relative behavior of faults and the required clearing time.