A blackout at NIU’s west residence halls lasting more than 30 minutes late Tuesday afternoon was caused by a faulty Commonwealth Edison power switch.

Bart Wilcox, a Com Ed spokesman, said electricity can be transferred from one powerline to another manually or mechanically, and the mechanical switch was faulty.

The power failure mainly affected Clare, a small town north of DeKalb, which lost all electricity, Wilcox said. Power was restored at 5:04 p.m., 32 minutes after the power went out.

About 2,500 customers were affected, he said. The complete area affected was unknown, but power company officials will repair the switch this week, he said.

Lincoln, Douglas, Stevenson and Grant residence halls were without power. The halls operated with backup generators.

The Office of Campus Recreation also lost power.