What was found
(CAN) 35 MINUTES BEFORE LANDING, PILOT HAD A FIRE LIGHT INDICATION WITH NO AURAL WARNING, THE STANDBY POWER LIGHT IMMEDIATELY CAME ON AND ALL THE NR 1 & 2 BUSS CIRCUIT BREAKERS POPPED. MAINTENANCE WAS CONTACTED IMMEDIATELY AND SUGGESTED RESETTING ALL THE CIRCUIT BREAKERS, AND CARRYING OUT A GROUND RUN, NO FAULTS WERE FOUND. YHM MAINTENANCE CONTRACTED AN AME IN THE AREA TO PERFORM A GROUND RUN WITH FULL ELECTRICAL LOAD WHILE OBSERVING FOR ANY FLUCTUATION OF THE ELECTRICAL SYSTEM, NO FAULT FOUND. WHEN THE A/C RETURNED TO YHM, MAINTENANCE PERFORMED A THOROUGH INSPECTION ON THE ELECTRICAL SYSTEM. THERE WAS A 30 AMP CIRCUIT BREAKER FOUND THAT HAD AN INCREASED RESISTANCE/OHM FLUCTUATION. CIRCUIT BREAKER WAS REPLACED P/N S1232-530. A/C RETURNED TO SERVICE AFTER GROUND RUNS PERFORMED.