An EPB substation fire knocked out power in the Shallowford Road-Highway 153 area Saturday evening.

John Pless, EPB spokesman, said Saturday that he did not know what led to the "pretty significant fire," but he said the company will investigate.

He didn't have a damage estimate Saturday night, but Pless said EPB had "lost one transformer, at least."

Power outages knocked out several traffic lights in the congested Shallowford Road, Jersey Pike and Chapman Road corridor along Highway 153 and Interstate 75. Chattanooga police manually directed traffic until power was restored.

Pless said the Smart Grid system automatically reconnected most of the residents affected by Saturday's fire within several minutes, but about a dozen customers had to be manually reconnected at the substation, which could not be accessed until fire crews cleared the scene.