The fire left hundreds of customers without power through Saturday morning.
Firefighters responded to flames shooting up at least five feet high from a manhole at the intersection where utility crews suspected the problem originated. At the height of the outage, some 500 customers were left without power.
By daylight, PECO officials brought in emergency generators to help affected customers.
However, some popular tourist attractions remained closed, including areas around the Independence Visitor Center.
There's still no word on what may have caused that fire, or when power will be restored.