§29.1357 Circuit protective devices

(a) Automatic protective devices must be used to m inimise distress to the electrical system and hazard to the rotorcraft in the event of wiring faults or seri ous m alfunction of t he sy stem or connected equipment. (b) The prot ective and cont rol devices in the generating system must be desi gned to de-energise and disconnect faulty power sources and power transmission equipment from their associated busses wi th suffi cient rapi dity t o provi de protection from hazardous overvoltage and other malfunctioning. (c) Each resettable circuit protective device must be designed so t hat, when an overl oad or circuit fau lt ex ists, it will o pen th e circuit regardless of the position of the operating control. (d) If th e ab ility to reset a circu it b reaker o r replace a fuse is essential to safety in flight, that circuit breaker or fuse m ust be located and identified so that it can be readily reset or replaced in flight. (e) Each essential load m ust have i ndividual circuit protection. However, i ndividual protection for each circuit in an essential load system (such as each position light circuit in a system ) is not required. (f) If fuses are used, there must be spare fuses for use i n flight equal to at least 50% of the number of fuses of each rating required for complete circuit protection. (g) Automatic reset circuit breakers m ay be used as integral protectors for electrical equipment provided there is ci rcuit prot ection for t he cabl e supplying power to the equipment.