By Scott DiSavino

June 29 (Reuters) - With a second heat wave poised to strike New York City this weekend, union workers at power company Con Edison may go out on strike which could leave consumers hot and bothered if their air conditioners don't turn on.

Union negotiators and New York power company Consolidated Edison Inc were still far apart on negotiations for a new contract on Friday, said John Melia, a spokesman for the union. He said talks were not going well.

The union membership has authorized its leaders to call a strike at midnight Saturday, when the collection bargaining agreement expires.

If the 8,500 Con Ed workers do walk off, that would leave managers and any crews the company can hire to fix whatever problems arise as 8.2 million New Yorkers crank up their air conditioners to beat the heat.

Still, with the possible strike coming on a weekend, when many businesses are typically closed, demand for power will be lower than a weekday. That would lessen the risk that the utility will have to reduce voltage, commonly called a brown out, as Con Edison was forced to do last week in Brooklyn and Queens when temperatures soared.

Several hundred customers also lost power as heavy usage strained some lines and equipment last week. The coming heat wave was forecast to last until Monday, and the mercury was not expected to hit last week's levels.

And demand could be even lower as New Yorkers take vacations with the Independence Day holiday falling midway through the week.

Still, the union stressed that without its skilled workers, the biggest U.S. city could be facing outages in a heat snap if a deal is not agreed.

"The public should know, especially in Brooklyn and Queens, that if (Con Edison) persists in failing to engage in meaningful discussions and forces a work disruption, the system shows every indication that it will not be able to hold up in another heat wave," Harry Farrell, President of Local 1-2 of the Utility Workers Union of America, stated in a release.

"There will be outages and Con Ed will not be able repair the damage," Farrell said.

Con Edison said in a statement the company, which has 13,000 employees including union members, "Looks forward to productive discussions with the union leadership on a new contract that is fair and equitable for our employees and customers."

The last time the union went on strike, in 1983, it lasted nine weeks, according to union spokesman Melia. In 2008, then Gov. David Paterson managed to broker a deal between union and management to avoid a strike, he added.


SUMMER SWELTER, GRID STRAIN

Temperatures in New York City were expected to reach 94 degrees Fahrenheit (34 Celsius) on Friday, 92 on Saturday and Sunday, and 90 on Monday before slipping into the 80s on Tuesday before the Fourth of July, according to AccuWeather.com. The normal high for this time of year is 83.

Demand for power in the city was expected to reach about 10,100 megawatts (MW) on Friday before dropping to 8,600 MW on Saturday and 8,100 MW on Sunday. Demand should return to 9,300 MW on Monday when the work week starts again, according to the state power grid operator. One MW powers about 1,000 homes.

Last week during the heat wave, demand peaked at about 10,700 MW. Con Edison set its all-time peak demand of 13,189 MW during a long heat wave in July of last year.

Con Ed, which serves about 3.2 million customers or roughly nine million people, said Friday morning about 100 customers were without power, which is normal for a utility of its size this time of year.