As the North State enters a nearly week-long excessive heat warning, electricity managers have called for a Flex Alert Friday. The California Independent System Operator manages the state power grid. The Flex Alert has prompted PG&E to ask its customers to conserve electricity from 3PM to 10PM Friday evening. A dramatic increase in residential air conditioning is expected, so to avoid overstressing the available power, people are asked to keep thermostats above 78 degrees, close drapes, unplug chargers and other equipment that’s not in use, and delay vacuuming, laundry, dishwashing and other high energy activities until after 10 O’clock Friday night.