What was found
DURING PREPARATION FOR ENG #2 COOLING BAROMETRIC SWITCH, OPS CHK FOUND DAMAGE TO A SCREW AT NACELLE ZONE VENT SOV. AFTER INVESTIGATING, WE FOUND THAT THIS SCREW WAS TOUCHING THE FEEDER CABLES. TWO CABLES GOT DAMAGED AND PRODUCED ARCING TO THE VALVE HOUSING SCREW. THIS DAMAGE OCCURRED DUE TO WRONG FEEDER CABLE CLAMP INSTALLATION. THE TWO CLAMPS WERE INSTALLED 180 DEGREES IN THE WRONG DIRECTION, WHICH LED TO NOT ENOUGH CLEARANCE TO THE VALVE BODY. LACK OF PROCEDURE KNOWLEDGE: DUE TO WRONGLY INSTALLED CLAMPS AT ENG #2 PERFORMED ENG 1 IDG POWER FEEDER PRIMARY INSULATION REPAIR AND REROUTE IAW SWPM 20-10-13, REV. 91. NO FURTHER DEFECTS NOTED.