Senator Schumer is calling for a federal investigation into the nation’s power grid amid blackouts that have hit cities coast to coast the past two weeks.

“If every time there’s a storm or there’s a heat wave we’re going to have large chunks of the country without electric power, something is wrong,”Mr. Schumer said yesterday. “What happened in New York is happening elsewhere and demands a national look.”

While attention in the city has focused on outages that left tens of thousands of northwest Queens residents without power for more than a week, sweltering summer temperatures and lightning storms have also caused extensive blackouts in parts of California and Arkansas, and in St. Louis.

Warning of even larger and more widespread outages, Mr. Schumer said the Department of Energy should investigate the cause of the blackouts and examine the grid for weaknesses and structural damage. Officials with the federal agency did not return calls for comment yesterday.

The state Public Service Commission has launched an investigation into the Queens power failure, but Mr. Schumer said he has little confidence in that agency’s independence.

The Democratic senator issued his demand on the same day as a congresswoman of Queens, Rep. Carolyn Maloney, issued a report finding that many businesses in the borough suffered financial losses that far exceed the $7,000 Consolidated Edison is offering in reimbursement for the extended outages.

Ms. Maloney’s office surveyed 63 businesses that lost power, and 62% reported incurring damages of more than $7,000. Less than one-third said they had insurance to cover the loss. Under state regulations, the $7,000 covers only damages resulting from food that spoiled due to lack of refrigeration.

Other Queens politicians have called for Con Ed to provide three months’ worth of free electricity to make up for the financial hardship, and Ms. Maloney said she supported that demand.

“Obviously, they’re not providing enough, nor is their scope large enough,” the congresswoman said in an interview.

Con Ed has stuck to the $7,000 figure, although officials have not ruled out an increase. A spokeswoman, Elizabeth Clark, said as of Saturday evening, the company had issued more than 1,500 reimbursement checks totaling $884,000.

The city is also offering low-interest loans of up to $10,000, but some businesses have said even that would not be enough.

The first in a series of City Council hearings is set for this morning at City Hall, and Con Ed’s chief executive, Kevin Burke, is likely to face intense questioning from lawmakers who have called for him to resign. After accusing the utility of lying about the extent of the outages earlier this month, lawmakers are planning to buck council tradition by making Mr. Burke swear an oath before he testifies.

Mr. Burke will also appear before a state Assembly hearing Thursday, and Wednesday he will deliver a preliminary report on the outages to Mayor Bloomberg. Utility officials say it will take weeks to determine why a series of feeder cables overloaded, leading to a power failure that cut electricity to more than 100,000 residents and businesses.

As for the heat, it may only get worse this week. The temperature could reach triple digits tomorrow and Wednesday, according to the National Weather Service.