As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING PHASE 1-5 INSPECTION, FOUND FLEX DUCT HAD CHAFED THROUGH THE INSULATION ON SEVERAL WIRE AND MAKE CONTACT WITH THE BARE WIRE SPINE OF THE FLEX DUCT. INDICATIONS OF ARCHING WERE NOTED. THE WIRE BUNDLE THAT WAS CHAFED IS THE R/H MAIN WIRE BUNDLE FROM THE AFT BULKHEAD J-BOX COMING FROM THE BOTTOM AND PASSING THROUGH THE AFT BULKHEAD VERTICAL SUPPORT BEAM LIGHTING HOLE. THE CHAFED WIRES ARE OUTBOARD OF THE VERTICAL BEAM.