PG&E Corp. said it was planning to pre-emptively cut power to about 361,000 customers in northern and central California in an effort to prevent wildfires, marking the largest such shut-off it has reported this year. The San Francisco-based utility started de-energizing electrical lines in the Northern Sierra region Sunday morning and said shut-offs would continue through Monday night in other regions, ranging from the San Francisco suburbs to wine country to small rural towns. The blackouts will affect customers in portions…