Considerations for Using Dual Indication in Aerospace Arc Fault Circuit Breakers (AFCB)

Most thermal circuit breakers have some form of indication to exhibit an overload condition, thereby triggering the maintenance crew to take appropriate action. However with the addition of arc fault sensing circuitry, the indication from the tripped circuit breaker could appear for two separate conditions, viz. arc fault trip and thermal trip. While it is important that the functionality of the circuit breaker is not compromised, it is equally important to account for the requirements of optimal dual indication and understanding the implication of the circuit breaker tripping during a thermal or arc fault.