A fire in an underground electric vault cut off power to 55 square blocks in Seattle’s commercial district, knocking out traffic lights, prompting the evacuation of several buildings and forcing others to close for the day. No injuries were reported. The majority of the affected downtown area is commercial and retail and few of the businesses have alternative power sources, City Lights spokeswoman Julia Greenlee said. “It really affects a major core of Seattle’s retail business,” Greenlee said. Firefighters gained access to the fire through building basements. Officials said power was likely to be restored by this afternoon.