Fire officials said the man, a contractor working in the area, was treated and released at the scene for smoke inhalation by Huron Valley Ambulance.
Crews were called to South Quad, located at 600 E. Madison, around 9 a.m. for black smoke coming from the building, Ann Arbor fire Battalion Chief Steve Lowe said.
The fire was contained to the high-voltage room.
"It was burning pretty good," Lowe said.
Electricians were called to the scene to cut the power to the room and firefighters went in to quickly extinguish the blaze.
Lowe said it was unknown where exactly the contractor who required medical treatment was when the fire broke out. The entire area around Packard, Division and Madison is affected by construction as renovation work appears to continue at South Quad and contractors work on building the new 600-bed graduate student housing dormitory at the former Blimpy Burger site.
Sidewalks were shutdown due to the construction and dozens of workers in the area watched fire crews put out the blaze.
Lowe said the fire destroyed a lot of complex electrical machinery in the high-voltage room and early damage estimates are around $250,000.
U-M fire officials continue to investigate.