A group of 66 Pennsylvania Power & Light Co. industrial customers, who curtailed their use of electricity Thursday afternoon (8/3) under a special rate plan, were cleared to return to their normal use levels at 6 p.m. as customer demand eased.

The request for the curtailments, called for by the five-state power pool that includes PP&L, was taken as a conservative measure to assure a balance between available electricity supply and a record- setting level of demand, according to Barry Trayers, PP&L's manager of Bulk Power Operations.

The industries asked to reduce power use today have special "interruptible" contracts with PP&L that give them a lower price for electric service in exchange for agreeing to reduce power during periods of emergency.

"Only after much consideration did we decide to ask interruptible customers to cut back on power use. It's an action we do not take lightly, but we felt it was needed to maintain reliable service to other customers," Trayers said.

"PP&L did not forcibly cut power to these companies," he explained. "We asked them to reduce power use in accordance with the terms of their contracts. Their compliance helped the power pool avoid taking other actions to conserve electricity."

The cooperation of interruptible customers reduced demand for electricity on the PP&L system by about 400,000 kilowatts during the hottest part of the afternoon.

The last time PP&L asked interruptible customers to reduce power use was during the power supply emergency in January 1994. The last time such a request was made in the summer was Aug. 27, 1993.

Electricity use by PP&L customers was lower Thursday than the day before, largely as a result of the requested curtailment. On Wednesday (8/2), PP&L customers set a summer record for electricity use in a one-hour period, with 6,153,000 kilowatt-hours, according to unofficial numbers.

Use also was lower on the power pool, which coordinates the distribution of power for more than 22 million people in Pennsylvania, New Jersey, Maryland, Delaware, Virginia and Washington, D.C.

"It's likely that without the emergency measures taken Thursday, we would have set records for both PP&L and the power pool," Trayers said.

Projected power use for Friday (8/4) is slightly below where it has been the past few days. PP&L does not expect to call for further customer actions to conserve electricity.

"As we have throughout the heat wave, we advise customers to use electricity wisely and to do whatever is necessary to assure their health and safety," Trayers stated.

PP&L serves 1.2 million customers in 29 counties of eastern and central Pennsylvania.