“We’ve been through this situation w ConEd time & again & they should have been better prepared — period,” Gov. Andrew M. Cuomo said in a post on Twitter on Sunday evening. He encouraged New Yorkers to check on their neighbors and said he was deploying 200 state police, 100 generators and 50 light towers to help people affected by outages.

Erneil Johnny, 31, a photographer who lives in Canarsie, said on Sunday night that the electricity in his home, and the traffic lights outside, had been out for a couple of hours.

He said the neighborhood was dark but calm. “I’m near the water and there’s a sea breeze. Everybody’s hanging out outside their house,” he added. “Luckily this didn’t happen at midday, when the heat was at its peak.”

Emily Prevost, 32, who lives in Park Slope, said her power went out on Sunday afternoon. It had yet to return by 9:30 p.m. “My A.C. made this really loud dying sound,” she said. “And then it started chirping like a bird. And it’s still chirping.”

While she waited for the electricity to return, she bought ice cream and tweeted at Con Edison for updates. “It was always a canned response,” she said.

P.S.E.G. Long Island had wrestled with its own power failure on Saturday night that left thousands without power in the Rockaways.

By Sunday night, both companies were asking customers across neighborhoods in Brooklyn and Queens to limit the use of electrical appliances. Con Edison s aid it had reduced voltage by 8 percent in affected areas to protect equipment and maintain service as repairs were made.