Firefighters in Trenton were called to Luther Towers in the 400 block of West State Street for an electrical fire late Wednesday night.
Officials say a water line in the senior housing high rise was leaking onto the building's main 30,000 volt power line.
The water caused the power line to spark and ignited a small fire in the basement.
Firefighters knocked the fire down quickly but the leak caused a short out and a total loss of power to the building.
Officials say they have no idea how long it will take to repair it.
"Lots of times these parts are specially made for the building capacity electric of what the building requires. It could have to be made or it could be found somewhere local or it could have to be flown in," explained Trenton Battalion Chief David Turner.
All the residents are staying at a nearby school that does have air conditioning.