What was found
WORKING INOP BLD FOUND CB'S FOR WATER HEATERS & DRAIN MAST POPPED. FOUND BURNED WIRES. *S/D* WIRES BURNED THRU AT STA 1681 , WL 208 DUE TO CHAFE THRU BY HOSE BAND CLAMP FROM IMPROPERLY ROUTED WIRES AND VENT HOSES WHICH LED TO ARCING AND BURN-THRU OF WIRES. BOEING NOTIFIED, AND NO PREVIOUS OCCURRENCES WERE NOTED. STRICTLY DUE TO IMPROPER ROUTING OF VENT HOSES AND WIRING BUNDLE WITH IMPROPER STAND-OFFS, AS VERIFIED IN IPC 38-31-56-004, FIG G. THREE OTHER AIRCRAFT INSPECTED FOR PROPER ROUTING, AND WERE IN ACCORDANCE WITH IPC ABOVE.