R/H Boost Pump Wire Burned.

Last week, mission from Riyadh to Melbourne, transit stop in Kuala Lumpur for 1 hr after 7 hrs flight. 2 hrs after airborne, the pilot called me to the cockpit and informed me that R/H aft boostpump Low Pressure light came on. As per crew checklist boost pump switch to be kept off.

Upon landing in Melbourne, noticed that the boost pump CB's in P62 PDP popped-out. Inspected the boost pump looks normal, however when i traced the wiring found burned wire about 1 ft from the pump itself. Defect put under MEL cat C, upon return to base, damaged wire repaired per Standard Wiring Practice Manual.

It is quite mysterious how the wires got burned, lightning strike? Landing was retracted as it happen 2 hrs after airborne. I noticed adjacent bolt to the burn area, probably arcing could be the caused.