With its high-voltage transmission lines repaired, Connecticut Light & Power restored power to 320,000 customers overnight, leaving less than 30 percent of its system without electricity Wednesday morning.
Officials from CL&P and the smaller United Illuminating said they will be able to estimate Thursday when substantial restoration will be complete to an electric grid shredded by Sandy, the third major storm to hit in 14 months.
“I want everyone to know this remains our top priority,” Gov. Dannel P. Malloy said at his morning briefing at the Emergency Operations Center in Hartford.

CLP outage map: Black means at least 91 percent without service. Yellow and beige are least affected. Gray is towns outside its territory.
Twenty-nine sewage treatment plants are running on back-up generators, but Malloy said rumors about the contamination of public drinking water or well water are untrue.
“We don’t have any proof of contamination,” Malloy said, but added that residents should boil drinking water if they have any concerns.
The state took more steps toward normalcy: Thousands of downed wires have been cleared from roads, more than 25 school districts re-opened, and many communities gave trick or treaters the go-ahead to make their rounds.
“I will be open for business,” said Malloy, who planned to be giving out candy bars at the Executive Residence in Hartford. “I am returning to the closest thing I get to normal on Halloween.”
UI restored power to marine terminals in Bridgeport and New Haven, important ports of entry for gasoline and diesel. In addition, the state has waived oversized weight limits on fuel trucks to stave off shortages.
But 1,500 people still were using shelters. Floodwaters are receding, but the governor said that hundreds of homes are uninhabitable, primarily in shoreline towns hard hit by a record storm surge on Long Island Sound.
Malloy is touring the eastern shore, with planned stops from Stonington to Branford. Lt. Gov Nancy Wyman is to inspect damage from Milford to Fairfield.
Wary of raising expectations after missing self-imposed deadlines after Tropical Storm Irene and last fall’s nor’easter, CL&P and UI have declined to make similar promises until completing damage assessments.
To monitor restoration, check the online outage maps: CL&P and United Illuminating.
About 40 percent of UI’s customers were without power Wednesday morning.
CL&P and UI each did signficant restoration work Tuesday, but their main focus was to assess damage and clear downed wires, allowing local and state crews to reopen roads. More crews will shift to restoration work Wednesday.
Both utilities already have dispatched hundreds of electricians to repair connections to individual homes, so they were will not face delays once line work is complete.
James P. Torgerson, the president of UI’s corporate parent, said he understands that customers want to know what to expect, especially those who lived through prolonged blackouts last year.
“I want to know,” said Torgerson, whose Branford neighborhood is without power. “My wife keeps calling me.”
He can refer her to CL&P. Branford is not in UI’s service area.
Mark Pazniokas can be reached at mpazniokas@ctmirror.org. Follow him on Twitter.