More than 15,000 customers, most of them in Ventura and Kern counties, had their power shut off by 10:40 p.m. Wednesday.
The utility said more than 263,000 remained under consideration for shutoffs.
The utility's Public Safety Power Shutoff program is designed to lower the risk of fires caused by damage to electrical equipment when strong winds are expected. Some of the most destructive wildfires in California's history have been linked to damaged electrical equipment.
Red flag warnings are already in effect for many areas of Southern California and are expected to continue through Friday night.
A map of communities from Ventura County to the Inland Empire that could be affected is available here.
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SCE customers can sign up for alerts to let them know if the power will be shut off.
Southern California Edison has about 5 million customers and is considering power outages for about 5.4% of them spread throughout eight counties.