Aug. 3--With air conditioners working overtime during this week's heat wave, American Electric Power customers in central and southern Ohio twice set power-use records as electricity grids across the country strained to meet surging demand.

AEP customers in those regions set a power-use record at one point Tuesday afternoon, using 4,431 megawatts, beating the 4,327 mark set Monday afternoon.

Numbers from yesterday, when temperatures remained in the mid- 90s, were unavailable.

Customers in central Ohio, like those in much of the eastern United States, were asked to conserve wherever possible, and some Downtown offices were dimming lights in response.

But as of yesterday evening, no major outage caused by the heat had been reported in the Columbus area, according to AEP and the Public Utilities Commission of Ohio.

"We are pleased that our system has operated well," said Melissa McHenry, a spokeswoman for Columbusbased AEP. "We try to keep our system as reliable as possible. We appreciate those customers who have been able to take those steps to conserve power."

Although central Ohioans suffered no major outages because of the heat, nearly 3,000 customers in Newark were without power yesterday because of a mechanical problem, McHenry said.

FirstEnergy customers in northern Ohio experienced outages Tuesday. Some, in Cleveland's western suburbs, were planned to lessen the burden on the electricity grid, but others were caused by heat-related mechanical problems, the company said.

A handful of outages during the dog days of summer aren't unexpected, said Shana Eiselstein, PUCO spokeswoman. The relative lack of power failures is evidence of new reliability standards in the 2005 Energy Policy Act, the investment of $518 million in Ohio in new-generation projects, and more than $80 million spent on new transmission capacity in recent years, Eiselstein said.

"All of the utilities have been very active about getting the word out to the customer to conserve," she said, also noting improved communication between utilities. "I think that what we're really seeing here are lessons learned in the blackout of 2003."

Such outages and others in the Columbus suburbs show that questions remain about customers getting "quality, reliable service throughout the year," said Ryan Lippe, spokesman for the Ohio Office of Consumers' Counsel.

"It's certainly too soon to say on the hot weather, let alone during this winter or during the rainy season," he said. "So we remain concerned."

Gov. Bob Taft urged Ohioans to conserve energy by doing things such as weather-stripping doors, replacing air-conditioning filters and installing programmable thermostats to use less energy.

Some Ohioans didn't need the encouragement. When temperatures started jumping in recent weeks, Sara English of Columbus adjusted the thermostat in her two-story home near Worthington from its normal 73 degrees to 75. She said she makes the switch each year during the summer's hottest days, to the chagrin of Justin, her 7- year-old son.

"He's been spending a lot of time in his little (kiddie) pool," English said. "But a couple of degrees (on the thermostat) will supposedly save you some money."

PJM Interconnection, which operates AEP's eastern transmission grid, reported a record yesterday when customers used 144,796 megawatts. The previous record of 144,000 was set Tuesday, breaking the record set in late July by nearly 5,000 megawatts. PJM serves 51 million people in 13 states and the District of Columbia.

One megawatt of electricity is enough to power 800 to 1,000 homes, according to PJM.

Before AEP's customers in central and southern Ohio set records this week, the previous high mark was on July 26, 2005, when 4,105 megawatts were used.

In August 1995, AEP set a peak of 3,378 in those areas that lasted for three years.

On Tuesday, AEP also set a record in its eastern territories, which includes Ohio, Indiana, Kentucky, Michigan, Tennessee, West Virginia and Virginia.

paul.wilson@dispatch.com