LOS ANGELES (NewsNation/KTLA) — As a persistent heat wave continues to scorch California, the body that runs the electric grid for most of the state asked residents Sunday to conserve electricity in a statewide Flex Alert.

The California Independent System Operator issued the voluntary call to consumers to conserve electricity from 3 p.m. to 10 p.m. for the next four days in order to prevent outages.

The ISO also told residents to prepare for the likelihood of more rotating electric outages.

The record-breaking heat wave, which brought triple-digit temperatures to some areas, is causing a strain on supplies and there is not enough energy to meet the increased demand, ISO said in the alert.

“Extended periods of heat also can cause generator equipment failures that can lead to more serious unplanned losses of power,” ISO said.

If consumers shifted energy use to morning and nighttime hours, it can help lower demand and avoid further outages.

On Friday, ISO declared a statewide Stage 3 emergency and ordered utilities to shed about 1,000 megawatts, prompting rolling blackouts across the state.

Between 3 p.m. and 10 p.m., the ISO is urging consumers to:

• Set air conditioning thermostats to 78 degrees, if health permits.
• Defer use of major appliances.
• Turn off unnecessary lights.
• Unplug unused electrical devices.
• Close blinds and drapes.
• Use fans when possible.

The heat wave is believed to be the worst in California in 14 years.

Several areas in Southern California either tied or exceeded record temperatures on Saturday, according to the National Weather Service, including Woodland Hills at 112 F and Burbank at 104 F.

The heat wave, which began Friday, could last through at least Wednesday or Thursday, NWS said.