History of Aircraft Wiring Arc-Fault Protection [History]

In both new and aging military and civilian aircraft, all critical power wiring has been typically protected against overheating by using combinations of thermal and magnetic circuit breakers or solid-state power controllers (SSPCs). However, the conventional types of these protective devices do not detect and react to hazardous arcing faults, and it is important that they do so to mitigate the risk of aircraft fires caused by aging, damaged insulation, wire chafing, wire breakage, chemical exposure, maintenance procedures, and contamination. Most aircraft electrical systems operate at 115 Vac, 400 Hz, both single and three phase. In addition to this ac power, they utilize 28 Vdc. Hazardous arcing faults can occur in all these power systems between parallel conductors, to ground, or in series (due to a broken or frayed wire or at a loose connection).