PJM Interconnection, the company that operates the Philadelphia area's electric grid, is asking the region's electricity users to conserve power this afternoon as "a precaution during the extremely hot, humid weather."

PJM, which serves 51 million people in 13 states from the mid-Atlantic to Illinois, directed the conservation request to customers in the eastern section of its grid, where it said electricity consumption may approach record levels.

The call specifically targets customers of Philadelphia's Peco Energy; Atlantic City Electric; Delmarva Power; Dominion; Jersey Central Power & Light Co. (JCP&L); Baltimore Gas & Electric Co.; Metropolitan Edison Co. (Met-Ed); Pepco; Pennsylvania Electric Co. (Penelec); PPL Electric Utilities; PSE&G; and UGI Utilities Inc.

"Demand for electricity is expected to increase as the excessive heat and humidity continue. PJM asks customers to conserve electricity, if health permits – especially between 3 p.m. and 7 p.m.," PJM said.

The company recommended these steps:

Closing curtains and blinds to keep out the sun and retain cooler air inside.

Postponing use of major electric household appliances such as stoves, dishwashers and clothes dryers until cooler evening hours.

If health permits, raising air conditioner thermostats.

Turning off unneeded electric appliances and equipment.

PJM said it had also called on "emergency demand response customers" to curtail their electricity use. "These customers receive a special rate or payments to eliminate or significantly reduce their use of electricity when told to do so," the company said.

Contact staff writer Jeff Gelles at 215-854-2776 or jgelles@phillynews.com.