Raleigh, N.C. — Thousands of Raleigh residents were left in the dark for more than two hours Friday night after an electrical substation off Glen Eden Road caught fire, authorities said.

A transformer at the Raleigh Blue Ridge Substation caught fire at about 7:30 p.m. Friday, Progress Energy spokeswoman Melissa Swindell said. Utility officials don't know what caused the fire, she said.

About 41,000 customers in northwest Raleigh were without power at the height of the outage, including Crabtree Valley Mall and the areas around Glenwood Avenue and Blue Ridge and Edwards Mill roads.

"You're talking about enough energy to power a quarter of the city," said Rusty Styons division chief of the Raleigh Fire Department.

No injuries were reported in the incident, and power was completely restored by 10 p.m.

"We're trying to get home, but the road is blocked," nearby resident Will Berry said.

Police had to direct traffic at numerous intersections, and Crabtree Valley Mall was forced to close early.

"The lights just went out, and everything just went pitch black for a while," mall employee Purcell Anderson said. "It's just really wild for the lights to go out, especially in this area."

Swindell said a mobile substation was being brought to the site to help handle demand, and most customers were shifted to other substations to restore power as quickly as possible.

The "relatively modest" fire was quickly contained, but firefighters had to wait until the substation was completely de-energized before they could put it out, Styons said.

"The good news about these substations, while they do create a significant inconvenience to the public with an outage for some number of hours, the truth is they are built intentionally with a lot of safety features," he said. "The safety systems built in ahead of time allow us the luxury to take our time and be safe."

The Raleigh-Durham International Airport's crash fire rescue truck was standing by to spray foam on the fire to neutralize the combustible oils feeding the fire, he said.

The Raleigh Honeycutt Substation, Raleigh Six Forks Substation and Leesville Wood Valley Substation also caught fire Friday night, Swindell said.

Power came back on immediately for customers served by the Honeycutt and Six Forks substations, she said. About 250 customers were without power for a short time because of the Leesville Wood Valley substation, she said.