About 1.5 million people in California are set to lose power on Today as a utility firm tries to stop damaged cables triggering wildfires.
Pacific Gas & Electric (PG&E) already faces an investigation by regulators after cutting supplies to 970,000 homes and businesses.
It announced that another 650,000 properties would face precautionary shut-offs on Tuesday amid high winds.
Wildfires fanned by the strong winds are raging in two parts of the state.
Thousands of residents near the wealthy Brentwood neighborhood of Los Angeles have been told to evacuate because of a wildfire that began early on Monday.
Celebrities including the actor-turned-politician Arnold Schwarzenegger are among those fleeing the fast-moving Getty Fire, which started near the Getty Center arts complex.
Further north in Sonoma County, a larger fire has forced 180,000 people from their homes.
California’s governor has declared a state-wide emergency.
Regulators had announced on Monday at a formal inquiry into whether energy utilities broke rules by per-emptively cutting power to an estimated 2.5 million people as wildfire risks soared.
They did not name any utilities but analysts said PG&E was responsible for the bulk of the “public safety power shut-offs”.
The company filed for bankruptcy in January after facing hundreds of lawsuits from victims of wildfires in 2017 and 2018.
Of the 970,000 properties hit by the most recent cuts, under half had their services back by Monday, the Associated Press reported.
Despite criticism that the precautionary blackouts were too widespread and too disruptive, PG&E said more would come on Tuesday and Wednesday because further strong winds were expected.
The company said it had logged more than 20 preliminary reports of damage to its network from the most recent windstorm.
In a video posted to Twitter on Saturday, Governor Gavin Newsom said the power cuts were “infuriating everyone, and rightfully so”.(BBC)