An American Airlines Boeing 777-200, performing flight from Raleigh/Durham (USA) to London Heathrow (UK), reported electrical problem.
Aircraft was enroute about 80nm southeast of Boston (USA) when the crew requested to divert to New York’s JFK Airport reporting an electrical backup system had failed disallowing them to continue into Oceanic Airspace, no assistance was needed.
The aircraft diverted to JFK for a safe landing about 45 minutes later. The airport authority reported the aircraft diverted out of precaution over a warning light of some sort.
The aircraft remained on the ground in JFK for about 3.5 hours, then continued the journey and reached London with a delay of 4.5 hours.