Maryland’s biggest utilities are expecting record-breaking power use this week as consumers crank their air conditioning in tandem with soaring temperatures.

Pepco and Baltimore Gas & Electric are asking consumers to cut back on power usage and set their thermostats no cooler than 78 degrees to help relieve pressure to the region’s power grid.

BGE is expecting to break its 2010 hourly ue record on Tuesday evening and Pepco is preparing to break its all-time peak — which was set at 6,895 megawatts in August 2006 — on Wednesday, spokesmen for the companies said.

On an average summer day, Pepco customers use roughly 5,300 megawatts per hour and BGE customers consume about 5,500 megawatts. One megawatt is enough to power roughly 1,000 homes.

BGE is expecting to reach a 6,900 megawatt peak Tuesday evening.

The utilities have said they have enough power to manage the demand, but warned that stress to the system increases potential for power failures.