Power was restored to all campus buildings early Monday morning after some residence halls in the South Quad lost electricity for nine hours. The electricity went out after a shortage in a main cable, but the cause for the malfunction is still unknown.

Kelly Miller, assistant director of housing, said Thomas and Lawson halls were the last buildings to regain power and electricity was restored between 4 a.m. and 4:30 a.m. Tuesday.

However, electricians and crews from facilities planning and management continued to work on equipment until 8 a.m. Subsequently, the crews took Monday afternoon to rest and were not available to comment on the cause of the outage or what damage occurred.

Leigh Morris, a public relations representative for Ameren CIPS, said his records did not show a power outage on campus and he did not know of any problems.

The main problem, Miller said, was between Ameren’s transformer and the university system, and university officials need to determine what happened.

Thomas Hall went dark Sunday night when a main power cable shorted out, causing smoke to filter in Thomas Dining Center at around 7:30 p.m. The smoke was sucked through underground service tunnels into Thomas and Lawson halls, causing the evacuation of those buildings.

Electricians also decided to cut off power to Andrews, Taylor, Lincoln, Stevenson and Douglas halls at 9:45 p.m., but power was restored at about 10 p.m.