A B747-400 FLIGHT CREW ON AN INTERNATIONAL OVER WATER FLIGHT EXPERIENCED SMOKE AND OVERHEATED PANELS IN THE GALLEY; AS WELL AS EICAS ELECTRICAL UTILITY BUS WARNINGS. THEY DECLARED AN EMERGENCY AND RETURNED TO LAND AT THE DEPARTURE AIRPORT.

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APPROX 1 HR 10 MINS INTO OUR FLT WHILE IN CRUISE AT FL320; ONE OF THE FLT ATTENDANTS CALLED ON THE INTERPHONE TO ADVISE THAT A PANEL IN THE ECONOMY GALLEY WAS VERY HOT TO THE TOUCH AND THAT ANOTHER FLT ATTENDANT COULD SMELL SMOKE. ALMOST SIMULTANEOUSLY; THE FOLLOWING EICAS MESSAGES APPEARED: ELECTRICAL UTILITY BUS L (EICAS) FUEL PRESSURE L (EICAS) FUEL OVRD 3 FORWARD (EICAS) FUEL OVRD 2 FORWARD (EICAS) FUEL PUMP 3 FORWARD (EICAS) SEVERAL FUEL PUMP STATUS MESSAGES E&3 CLEANING SUPPLY FAN (STATUS). I DIRECTED THE FO TO GO TO THE ELECTRICAL UTILITY BUS L CHKLIST AND WE RAN THAT. WE IMMEDIATELY CONTACTED DISPATCH AND MAINT VIA SATCOM. I DE-POWERED THE L UTILITY BUS USING THE SWITCH. WE DIRECTED THE FLT ATTENDANTS TO PULL THE CIRCUIT BREAKERS ON THE PANEL. FLT ATTENDANTS RPTED THAT THE PANEL STARTED TO COOL DOWN AFTER WE REMOVED ELECTRICAL PWR FROM THE UNIT. THE SMOKE HAD SUBSIDED AND THERE WAS NO SIGN OF A FIRE. WE TOLD THE FLT ATTENDANTS TO CONTINUE TO MONITOR THE PANEL FOR ANY SIGN OF FIRE AND KEEP US POSTED. WE KEPT LOSING CONTACT WITH THE FLT ATTENDANTS AND HAD TO RECALL THEM SEVERAL TIMES. WE AWAKENED THE RELIEF PLTS. I DIRECTED ONE OF THEM TO GO TO THE GALLEY AND SURVEY THE SITUATION. I DIRECTED THE OTHER RELIEF PLT TO MAN THE INTERPHONE WHILE THE FO COORDINATED WITH ATC AND RAN THE CHKLIST. I CONTINUED TO FLY THE ACFT WHILE CONSULTING WITH MAINT AND DISPATCH. THE RELIEF PLT RPTED THAT THE PANEL WAS HOT BUT COOLING DOWN AND THERE WAS NO SMOKE OR SIGN OF A FIRE. MAINT WAS SUGGESTING SEVERAL TROUBLESHOOTING STEPS. I WAS MORE CONCERNED ABOUT STARTING A DIVERSION TOWARDS A SUITABLE ARPT. IT WAS OBVIOUS TO ME THAT WE WERE NOT CONTINUING ACROSS THE OCEAN WITH THIS SITUATION UNRESOLVED; ESPECIALLY WITH SEVERAL FUEL PUMPS DE-POWERED AND AN UNKNOWN SOURCE OF THE HEAT; SMOKE; AND ELECTRICAL ANOMALIES. I TOLD MAINT TO STAND BY ON THE TROUBLESHOOTING AND I ASKED DISPATCH 'WHERE ARE WE GOING TO GO?' HE STATED THAT EVERYTHING LOOKED FINE WX WISE. I HAD PREVIOUSLY LOOKED AT THE WX AND KNEW THAT ZZZ2 HAD RAIN AND GUSTY XWINDS; AND ZZZ WAS FINE. I TOLD DISPATCH THAT WE WOULD LIKE TO BEGIN AN EMER DIVERT TO ZZZ; AND THAT WE WOULD IMMEDIATELY DIVERT TO ZZZ2 IF THE SITUATION WERE TO BECOME MORE SERIOUS. HE CONCURRED. WE DECLARED AN ADS EMER; TURNED OFF COURSE AND BEGAN AN EMER OFFSET TO THE N OF COURSE; AND DSNDED TO FL315 WHILE TRYING TO GET A RE-CLRNC. SOON THEREAFTER; WE GOT A CPDLC CLRNC TO ZZZ AT FL320. WE DISCONTINUED ANY FURTHER TROUBLESHOOTING WITH MAINT IN AN EFFORT TO PREVENT FURTHER PROBS. FO REVIEWED THE DIVERSION CHKLIST AND WE DETERMINED THAT ALL PERTINENT ISSUES HAD BEEN ADDRESSED. WE ADVISED THE PURSER THAT WE EXPECTED A NORMAL LNDG IN ZZZ AND I MADE A PA ANNOUNCEMENT TO THE PAX. AT THIS POINT; WE TURNED OUR ATTN TO OUR NEED TO DUMP FUEL. WE CURRENTLY WEIGHED ABOUT 797.0 LBS. I CONSULTED WITH MAINT AND DISPATCH AND THE REST OF THE CREW AND IT WAS AGREED THAT WE WOULD DUMP DOWN TO 670.0 LBS FOR AN OVERWT LNDG. I DIRECTED THE RELIEF PLT TO RUN THE FUEL JETTISON CHKLIST AFTER CAREFULLY VERIFYING THE FUEL TO REMAIN WITH ALL 3 PLTS. THE DUMP TOOK ABOUT 1 HR TO DUMP 135.0 LBS; FROM 315.0 LBS TO 180.0 LBS; BECAUSE WE HAD SEVERAL INOP PUMPS. WE HAD TO HOLD AT XXX FOR ABOUT 15 MINS TO COMPLETE THE DUMP PROC; THEN BRIEFED AND COMMENCED A VISUAL APCH TO ZZZ RWY XXR BACKED UP BY THE ILS. THE LNDG WAS NORMAL AND SMOOTH. EMER EQUIP WAS STANDING BY. WE TOLD THEM NO FURTHER ASSISTANCE WOULD BE REQUIRED ONCE WE CLRED THE RWY. WE TAXIED TO THE GATE AND DEPLANED THE PAX. AFTER LNDG; I DEBRIEFED THE FLT CREW. WE ALL FELT THAT THE DIVERSION HAD BEEN SUCCESSFULLY ACCOMPLISHED WITHOUT PROB. WE WENT DOWN AND DEBRIEFED THE FLT ATTENDANTS. DURING THE DEBRIEFING; IT WAS MENTIONED BY ONE OF THE FLT ATTENDANTS THAT HE HAD EXPERIENCED THE SAME PROB AT THE GATE AT ZZZ ABOUT 1 OR 2 WKS AGO AND THAT THE FLT HAD CANCELED AS A RESULT. IN THE EVENT HE DESCRIBED; THERE WERE SEVERAL HOT PANELS IN THE GALLEY AREA. WE ARE NOT SURE IF THIS WAS THE SAME ACFT. PRIOR TO OUR ORIGINAL DEP; THE FLT ATTENDANTS RPTED THAT THE ECONOMY CHILLERS WERE INOP. WE ENTERED THAT INTO ACARS AND CALLED MAINT ON THE RADIO TO ADVISE. MAINT CAME ONTO THE ACFT TO REPAIR A BROKEN LIGHT. WE REMINDED THE MECH ABOUT THE CHILLER PROB. ITEM ENDED UP GETTING DEFERRED. AFTER LNDG; WHEN I WENT BACK TO SEE THE PANEL IN QUESTION; I DID NOT OBSERVE ANY DEFERRED STICKERS ON THE CHILLER PANEL NOR ANY CIRCUIT BREAKERS OPENED AND CAPPED IN ACCORDANCE WITH THE DEFERRAL. ALSO; ABOUT 15 MINS BEFORE THE EVENT OCCURRED; ALL ENTERTAINMENT AUDIO IN ECONOMY CLASS BECAME INOP. WE WERE COMMUNICATING WITH MAINT ON ACARS ABOUT THIS PROB WHEN THE EVENT OCCURRED. THE ONLY REAL PROB THAT I NOTICED DURING THE EVENT WAS THAT THE FO AND I BECAME TASK SATURATED WHILE TRYING TO COORDINATE WITH MAINT; DISPATCH; AND THE FLT ATTENDANTS. THERE WAS A LOT OF INFO GOING BACK AND FORTH; AND THE SITUATION IMPROVED A LOT WHEN WE WERE ONCE AGAIN ASSISTED BY THE RELIEF PLTS. IN THE END; I FELT THAT THERE WAS GOOD COORD AMONGST OUR CREW AND BTWN US; DISPATCH; MAINT AND ATC. I FELT THAT OUR TRAINING SERVED US WELL IN DEALING WITH THIS SITUATION.