Firefighters were called to a fire at an electrical substation on Andover Road in Orpington.
The transformer of a single storey electrical substation, which transfers electrical energy from one electrical circuit to another, was destroyed by fire. Around 400 properties in the area were temporarily left without electrical power. There were no reports of any injuries.
The Brigade's 999 Control Officers took 8 calls to the fire.
The Brigade was called at 0232 and the fire was under control by 0411. Two fire engines and around 10 firefighters from Orpington fire station attended the scene.
The cause of the fire is under investigation.