University officials have isolated the problem that caused Monday’s two-hour power outage, according to Jack Colby, associate vice chancellor for facilities operations.

A cable that shorted out in a manhole under Dan Allen Drive in front of Bragaw Residence Hall caused the problem.

“When a cable like that shorts the ground, there’s a large current that takes out the other protective devices back at the substations,” he said.

When circuit breakers did their jobs to protect the substations, the power went out, Colby said.

“These large circuit breakers are there to protect the system from something like that,” he said.

“What we tried to do is isolate where the short is, and then we open switches on either side of the system to isolate that fault,” Colby said. “Then we close in switches to reenergize the lines that are still good”

The broken circuit served electricity to about 12 buildings, Colby said, but the University restored power to each of them.

The second portion of the power outage last night came from workers testing different circuits to see which ones were still functional, according to Colby.

“Unless we know exactly where the location of the circuit is, we just have to go through and randomly open switches and test that section of line,” he said. “One of the first sections that we tested was the one that had the fault in it.”

The University had not pinpointed the reason that the circuit was broken, Colby said, as there are a number of options.

The cable could be deteriorated or moisture could have worked its way into the circuit, he said.

While buildings on campus had electricity Tuesday, the outage had interfered with some students’ activities the day before.

Graham Groseclose, a freshman in sport management, said his Internet service in Lee Hall was inactive until Tuesday evening.

“I had a quiz on Vista, so I had to go somewhere that had Internet so I could do it,” he said.

Groseclose said Monday night his residence hall staff was helpful in moving people to other activities during the power outage.

Joe Boyle, a freshman in engineering, said he was going to eat when the power went out.

“I was going out to dinner, so I had to go to Hillsborough Street to eat,” he said. “I was going to go to a Scholars event but [the power outage] sort of messed up my schedule.”