Also Tuesday, the National Transportation Safety Board said it will send two more investigators to Boston to examine the Japan Airlines plane. The NTSB says the battery had "severe fire damage."
The fire happened on the ground Monday, with no passengers on board. But in-flight fires can be catastrophic, so the matter is getting close scrutiny by aviation authorities.
United Airlines says it checked its own 787s overnight. It would not say what the inspections found, but the Wall Street Journal reported the airline found improperly installed wiring on one of its 787s.
Boeing says the problem appears to be unrelated to previous electrical problems on the 787. Boeing Co. shares have fallen nearly 5 percent since the fire was reported.
It was the first of two issues this week involving a Japan Airlines 787 in Boston.
Massachusetts Port Authority spokesman Richard Walsh said the Boeing 787 was towed back to the gate for evaluation early Tuesday afternoon after about 40 gallons of fuel spilled. He said the plane had 178 passengers and 11 crew members on board.
A JAL spokeswoman said the crew reported a "mechanical issue" before returning to the gate.