Norwich — A widespread power outage across the city late Tuesday morning forced Norwich Free Academy to dismiss students early and caused confusion with traffic signals gone dark at some intersections.

Norwich Public Utilities spokesman Chris Riley said power was restored for everyone impacted shortly after 1 p.m. The outage lasted about an hour and 20 minutes in total.

NPU's investigation into the cause of the outage was ongoing, Riley said.

While widespread, the outage also was sporadic, with some city schools without power, some with power and some with partial power, school officials said.

Power initially was restored to some customers quickly through rerouting of power from areas of the city that had not been affected by the outage, NPU officials said in a statement.

"We understand that this is a frustrating situation for many of our customers," the statement said. "But please keep in mind that NPU is working as hard to restore power as soon and as quickly as we can."

NFA spokesman Michael O’Farrell said most of NFA was without power, but the Bradlaw Building on the east edge of campus still had power. NFA instructed students to go to their building’s fire drill waiting areas on campus, and school buses were called for the 12:30 p.m. dismissal. NFA sent robocalls to parents and posted campus alerts on the academy’s website and social media outlets.

Norwich police assisted the buses with traffic control at traffic lights near NFA that were not in service, O’Farrell said.

Norwich Public Schools could not dismiss early, because NFA and the public schools use the same buses. School officials said emergency lights and fire alarms continued working in all public schools. Teachers’ Memorial Middle School was operating on a generator. The John B. Stanton and Uncas schools had no power.

c.bessette@theday.com