SHELTON — United Illuminating announced Friday that it is expanding its restoration effort as crews encounter extensive damage in the areas hardest hit by Thursday’s storm.

As of 2 p.m. Friday, 546 (2.93 percent) of the 18,632 UI customers cut off by the storm in Shelton are without power. UI officials said the vast majority of the outages were concentrated in Shelton, Hamden, North Haven, New Haven and North Branford.

UI officials on Friday said that there will be nearly 600 line and tree workers, damage assessors and other field personnel working to restore power to approximately 13,000 of its overall customers who were still without service as of noon Friday.

Most of those should be back on by Friday evening, or Saturday at the latest, UI officials said. The exception will be customers in areas where damage is so severe that crews will have to rebuild the electric system. They expected those customers to be restored by Monday.

UI President and CEO Tony Marone, who joined Governor Ned Lamont, U.S. Sen. Richard Blumenthal, D-Conn., and other officials at a news conference Friday morning, said the devastation in those communities is severe and highly concentrated.

“During the day today, we’ll bring the number of outages down significantly, but there are parts of the system where the damage is really extensive, so we’ll need to rebuild the infrastructure in those areas. That will likely take a day or two,” Marone said Friday. “We have all the resources we need and, considering the limited area of focus, we’ve got as many crews as can safely work, especially in a COVID environment.”

At the news conference, both Lamont and Blumenthal praised UI’s efforts.

“UI has impressed me because they’ve had smart meters in place going back a decade,” said Lamont. “They can remotely see where the damage is. They can remotely see whose lights are on and whose lights are not on, so they can target the resources where they need to be.”

Blumenthal said: “I’ve been heartened and encouraged by what I’ve heard from UI. They seem to have been prepared and they are on the job and working to get the power back.”

UI reiterated that customers should stay far from downed wires, which can be live and dangerous even if they show no signs of being energized. Customers are advised to keep kids and pets inside, and never drive over a downed wire. Always report any downed wires to UI at 800-722-5584.

To report an outage, visit uinet.com or call 800-722-5584. Customers can also report outages using the company’s new mobile app, available from the Apple Store and Google Play. Or, they can report outages via UI’s mobile alerts system: text “OUT” to 839-884. Registration is required.

Sign up for free Outage Alerts at uinet.com to be notified by text, email or phone when you lose service and for restoration updates. Or sign up for free text alerts by texting “REG” to 839-884.

brian.gioiele@hearstmediact.com