The remaining fire is isolated at one transformer -- or possibly two -- at the LADWP's approximately 200 feet x 200 feet building at 560 S. San Julian St. between Fifth and Sixth streets in downtown Los Angeles, which houses several of the utility's transformers.
The fire was reported at 12:23 a.m. Saturday, said LAFD spokeswoman Margaret Stewart.
The fire will continue to safely burn itself out, fire authorities said.
LAFD crews are allowing the flames to burn off the high voltage electrical equipment "while ensuring the exposed building is defended and all windows closed to prevent smoke infiltration," Stewart said.
Firefighters are also defending an exposed apartment building and are not using water to douse the flames, due to the high voltage electrical equipment in the facility, Stewart added.
All pedestrians around the building are being moved to a safe location and firefighters are waiting for DWP representatives to arrive at the scene, fire authorities said.
No injuries were reported.