Norwich — Equipment failure at a Norwich Public Utilities substation in Greeneville caused Tuesday’s 90-minute power outage across the city that forced Norwich Free Academy to dismiss school early, Three Rivers Community College to go remote and required police to direct traffic at intersections with dark traffic signals.

NPU spokesman Chris Riley said a piece of equipment in the North Main Street Substation failed about 11:40 a.m. and knocked out power to an estimated 2,500 customers.

“We are still evaluating whether the piece of equipment can be repaired or if it needs to be replaced,” Riley said.