Pacific Gas & Electric, the nation’s largest utility provider, announced Tuesday that it had cut off power to 51,000 customers in Northern California. The shutoffs, a precaution to prevent power equipment from sparking wildfires in periods of high wind and heat, come as gigantic wildfires including the Dixie Fire are battering the region, destroying homes and even an entire town. The cuts will affect 18 counties. The company said it expects to restore power to affected customers by Thursday. Earlier this month, PG&E said its equipment may have started a wildfire that eventually became part of the Dixie Fire.