Because of exceptionally heavy demand for electricity in the mid-Atlantic region, Pepco and other utilities in the regional PJM Power Pool reduced system voltage by 5 percent this afternoon.

PJM and Pepco urgently request that customers cut back virtually all their non-essential electricity use, including air conditioners, unless it is equipment required for health and safety purposes. PJM companies request this action to help prevent more serious problems with power supply and delivery. Today's energy emergency is due to extremely hot weather and high customer demand that is challenging the PJM companies' ability to deliver electricity.

The voltage reduction will not be noticeable to the vast majority of customers, because most computers, motorized equipment and appliances can generally operate satisfactorily at lower voltages. Once operating conditions on the PJM system return to normal, the voltage reduction will be lifted.

The PJM power pool serves 13 states and the District of Columbia.

NOTE: A volt is a unit of electrical pressure that pushes electrons along a conductor. This is similar to the pressure that pushes water through a pipe. Most motors and other appliances are designed to tolerate a voltage variation of plus or minus 10 percent.

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Pepco, a subsidiary of Pepco Holdings, Inc. (NYSE: POM), delivers safe, reliable and affordable electric service to more than 750,000 customers in Maryland and the District of Columbia.