As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER HOOKING UP EXTERNAL POWER, NOTICED ARCING COMING FROM RECEPTICLE. DISCONNECTED CORD FROM A/C. RECEPTACLE HAD BURNED. REPLACED EXTERNAL POWER RECEPTACLE IAW M/M. OPS CHECK GOOD. ETOPS CATEGORY 'E': PROBLEMS WITH SYSTEMS CRITICAL TO ETOPS.