Utility crews restored the power around 9:30 p.m.
Public Works Commission utility crews say it appeared underground power cables running between three transformers Short-circuited and caught fire.
Firefighters quickly brought the electrical fire under control. Crews used hand held extinguishers on the burning wires.
"We extinguished each one of them, put dry powder on them - on the electrical fire - that allowed them to get in there and work on it," Fayetteville Fire Department Commander Eric Tipton said.
Utility crews worked into the evening pulling and connecting new lines. They say the underground lines they replaced were old and some of the insulation was cracked and brittle. They say the lines were due to be replaced in several months.
About a half dozen stores and offices on the south side of Person Street lost power during the incident.
"Our beer is hot now. All our coolers are shut down," Tavern Owner Geana Corella said. "I still have some renovations to do, so I wasn't able to do any of that."
Rodney Chamberling says he heard and felt the blast at his restaurant.
"We saw flames coming up about four to five feet off the ground and manhole covers were thrown off the sidewalk," he said.
Firefighters say it's lucky no one was hurt. The explosions could have hurt downtown visitor Lindsey Russell.
"I know these things happen but it was the scariest situation I've ever been in," she said.
The Pittsburgh resident says she and a friend were sightseeing on Person Street when the sidewalk started shaking and the manholes around them started belching smoke and fire.
"Whenever the earth trembled, and the ground shook like an explosion that was the scariest part," she said.
"Black smoke started coming up from the first manhole," Russell's friend Farrah Huzzy said. "We walked a little bit more all of a sudden the second one blew up about three to four feet from the ground, went on one side then fire started came up."