B777 Captain was informed of a smoky smell in the cabin during an oceanic flight. Cabin electrical systems were deactivated then complied with handbook procedures and the smell dissipated.

Narrative

Shortly after halfway point; and while climbing from FL360 to FL370; Purser called cockpit and advised of a faint smoky smell near row 46. I initiated an ACARS message to Maintenance Control. Two or three minutes later; Purser called back to say that the odor was much stronger. She informed me that no smoke was visible; but it was a strong smell. At this point; I turned off the IFE/Seat power and Cabin Utility switches; and also discontinued ACARS and called Dispatch on the Sat Phone. I had Dispatch patch through to Maintenance Control immediately. While talking to Dispatch/Maintenance Control; Purser notified me that the smell was lessened somewhat. At about the same time; a status message displayed Bulk Cargo Ventilation Fan. We did not know if this was because of the IFE/Cabin switches that we had turned off. Within a few more minutes; Purser again notified us that the smell was worse. First Officer and I quickly ran through the smoke procedures in the handbook; and turned off the recirc fans. While talking to Maintenance Control; we also turned off the gasper switch; and then the cargo heat switches. All this transpired in about 20 to maybe 30 minutes; and the smell eventually dissipated. We also had a Firefighter in the cabin; who assisted the flight attendants in identifying the smoke/odor. The flight attendants thought it was electrical smelling; and this was confirmed by the firefighter. He suggested it could be electrical; or a rubber burning smell. With concurrence of Maintenance Control; we decided to leave the components off that we had turned off; for the remainder of the flight. Maintenance Control also gave us a backup plan to go into the EE compartment to pull additional circuit breakers. We decided to do this only if the smoke returned. Dispatch advised ATC of our situation; but we decided to not declare an emergency at that time. The remainder of the flight was normal; with the exception of the passenger/galley/entertainment items that we had powered off. I did issue a cabin advisory to the Purser; with a planned normal approach and landing. I gave a verbal briefing to the FAM over the interphone. Dispatch; Maintenance Control; First Officer; Purser; FAMs and the Firefighter all did an outstanding job. It was a very busy time for a bit; while trying to converse with Dispatch/Maintenance Control/First Officer/Cabin and all; but we got everything done and covered I believe. The Sat Phone worked flawlessly. One area of confusion was the fact that there were numerous procedures for smoke problems; and it took a few extra minutes to go through those pages in the Handbook. Since there was no visible smoke; it made it harder to isolate the problem area; while at the same time helped us in not having a real fire and associated passenger hysteria. I admit that my adrenaline was spiked some; but I believe we all did our required tasks to isolate the problem. Also; after landing; I did second guess myself with turning off the IFE/Cabin switches so rapidly; but after re-consideration; think it was proper and prudent. At this point I don't know if the smoke was from that Bulk Cargo Ventilation Fan; or something else; but being over 2 hours away from an airport; powering off the cabin items that we did was correct as well.