South Carolina Electric & Gas customers used the most electricity the utility has ever recorded for a 24-hour period during the bitter cold on Tuesday.

More than 600,000 customers consumed 101,118 megawatt hours. The previous high mark of 98,785 megawatt hours was set Aug. 10, 2007, the company reported Wednesday.

Some 50,000 people lost power Tuesday statewide, including 9,000 in hard-hit Charleston County, where residents shivered amid high temperatures reaching only 33 degrees. By 4 p.m., service was restored to all but 500 customers, the Cayce-based utility said.

On Wednesday morning, SCE&G urged customers to conserve energy where possible and to unplug non-essential appliances and devices between 6 a.m. and 9 a.m. Spokesman Eric Boomhower reported no recurrence of Tuesday's weather-related outages.

About 50 customers in Charleston County were without power at around noon Wednesday, but the situation was unrelated to the previous outages, Boomhower said.

Problems with the power supply happened Tuesday when some generating plants experienced weather-related mechanical failure.

The 605-megawatt Williams Station near Goose Creek shut down automatically when bitter cold affected normal operation of a transmitter involved with regulating pressure in the plant's boiler system, officials said.

Space heaters and other measures were employed to prevent a recurrence of the problem Wednesday, SCE&G said.

Other plants affected by the weather included Urquhart Station, Fairfield Pumped Storage, Wateree Station and McMeekin Station.

SCE&G implemented rolling blackouts on Tuesday morning to manage the power-supply problem by temporarily cutting electricity for 15-minute periods.

Santee Cooper curtailed the electric supply to some industrial customers. "Otherwise, we would have set a new record as well," said spokeswoman Mollie Gore.

The customers agree to a temporary reduction in the power supply in exchange for lower rates, she said.

About 200 customers in the Myrtle Beach area lost power, she said.

A spokesman for Berkeley Electric Cooperative could not be reached for comment on how the weather affected power consumption. No co-op customers lost power Tuesday, the utility reported.

SCE&G customers concerned about higher weather-related energy costs may enroll in the budget billing program, which projects energy charges for the next 12 months based on usage history and spreads that amount over a dozen equal payments, the company said Wednesday.