HOUSTON -- A power outage that brought several downtown Houston businesses to a standstill Thursday was finally fixed 11 hours later, KPRC Local 2 reported.

Jurors were sent home and some students were relieved to learn of the large outage since it forced officials to cancel court and classes.

Five circuits inside a manhole in the 500 block of McKee Street near Elysian Street caught on fire at about 4 a.m. causing damage to an underground distribution line near the University of Houston-Downtown campus. The system was fixed and all power was restored by 3 p.m.

CenterPoint officials said a cable failure from an unknown cause at its Gable Street substation caused the outage of five circuits. Those circuits carried electricity to more than 300 commercial customers.

The following buildings were affected.

Harris County Family Law Center
Harris County Juvenile Justice
Islamic Temple, 202 Main Street
King George Hotel, 1418 Preston Street
Houston Area Urban League Building, 1301 Texas Street
U.S. Post Office, 401 Franklin Street
Ben Milam Hotel, 1521 Texas Street
Christ Church, 509 Fannin Street
Harris County Cotton Exchange Building, 1310 Prairie Street
Great Southwest Building, 1314 Texas Street
University of Houston Downtown Campus, 1 Main Street

Several streetlights in the area also did not functioning properly.

Authorities said about 20 minutes before the power went out, lights at several buildings in the area began flashing and alarms at businesses and residences began sounding.

Crews with CenterPoint Energy immediately responded to the area and began replacing cables.

Substations, which serve as a junction point on the electrical network that connects power plants, high voltage transmission lines and lower distribution lines, have two purposes: to switch circuits and step down voltage to appropriate levels for distribution.

CenterPoint said devices in place to detect faults and isolate equipment from further damage worked as designed.

The University of Houston-Downtown at 1 Main Street canceled classes until 4 p.m. Students and faculty were asked not to report to the university until then.

"A lot of the faculty depend on using computers for their presentations, so we felt at this point that it was probably better not to have classes during the day," a spokesman for the university told KPRC Local 2.

All court dockets were canceled at the Harris County Family Law Center. Staff members were expected to respond to work, but jurors were sent home.

Harris County 11th District Court Judge Mark Davidson said the seven-floor building's lights, air conditioning and elevators were not working because of the outage, which would have made it difficult and dangerous for people to work or hold court in the building.