United Illuminating, which still has 135,000 of its 320,000 customers without power, said it was getting more workers from far-flung places to help with the restoration efforts.
As of 9 p.m. Wednesday night, 31 percent of Shelton (5,430 customers) was still without power.
Tony Marone, a senior vice president, said at a 4 p.m. briefing on Wednesday that the company had 700 field personnel working at the height of the restoration efforts after Tropical Storm Irene.
By the end of Thursday, he said, there would be 1000 workers in the field, including contingents from Kansas City, Nova Scotia and 100 new line workers from Michigan.
"We recognize that each day that unfolds, the patience diminishes," he said.
Now that the safety and assessment work is largely done, Marone said, customers should begin to see the numbers of those regaining power start to "jump up."
"We still have a lot of work to do," Marone said.
An estimate of when 95 percent of customers will be back in business is expected from UI on Thursday morning.
"I know power is the No. 1 issue for everyone," Gov. Dannel P. Malloy said earlier in the briefing. Malloy said he would hold the utilities accountable to the estimates they give on Thursday.