WASHINGTON (REUTERS) - Officials investigating the fire on an Ethiopian Airlines 787 in London last week are focused on how condensation in the plane and a possible pinched wire in an emergency beacon may have sparked the blaze, according to people familiar with the probe.

The US Federal Aviation Administration (FAA) said on Friday it will call for inspections of the beacons made by Honeywell on Boeing 787 jetliners, but stopped short of requiring airlines to disable or remove the devices, as British authorities investigating the fire had recommended.

The FAA said inspections should ensure wires are properly routed, and should look for pinched wires or signs of unusual moisture or heat. It gave no further details on how those factors may have contributed to the fire.

One source close to the inquiry, however, told Reuters that investigators had found a pinched wire in the casing of the emergency locator transmitter (ELT) aboard the aircraft. The news comes after the British Air Accidents Investigation Branch (AAIB) on Thursday said the Honeywell beacon was the likely source of the fire, but said it was still trying to understand what ignited the plane.

The July 12 fire rekindled concern in the industry about Boeing's advanced carbon-composite Dreamliner, which was grounded for more three months this year after two incidents involving overheated lithium-ion batteries. The AAIB said the London fire was not related to those batteries.

The Honeywell ELT is delivered fully assembled and is installed by Boeing. The unit that was involved in the fire had not been opened, suggesting the pinched wire originated at the Honeywell plant, according to one person familiar with the investigation.

Honeywell declined to comment. Boeing declined to comment on the investigation but said it is working with airlines to either inspect or remove the beacons to meet regulatory guidelines.