What was found
ACFT WAS ENGAGED IN A LOCAL TRAINING FLIGHT WITH STUDENT PILOT FLYING ON FINAL APPROACH WHEN "ALT OFF" ANNUNCIATOR ILLUMINATED AND AMMETER SHOWED DISCHARGE. INSTRUCTOR COMMANDED THE OVERSHOOT AND TOOK CONTROL OF THE ACFT. AN EMERGENCY WAS DECLARED AND THE INSTRUCTOR ‘ACTIONED’ THE "ALTERNATOR FAILURE" CHECKLIST INSTRUCTIONS. A NORMAL CIRCUIT AND LANDING WAS CARRIED OUT WITHOUT FURTHER INCIDENT. ACFT WAS MET BY ARFF POST LANDING. NO EVIDENCE OF FIRE WAS NOTED AND ACFT WAS RELEASED TO MXE. TROUBLESHOOTING REVEALED THE MAIN PWR WIRE WAS BROKEN CLOSE TO ALTERNATOR TERMINAL, ONLY FACTORY HEAT-SHRINK LAYERS AND INSULATION HELD CABLE TOGETHER. WIRE WAS PREPARED AND A NEW TERMINAL INSTALLED. ACFT WAS RETURNED TO SERVICE FOLLOWING A SUCCESSFUL SYS TEST.