A power outage that began at 5:40 a.m. Friday left more than 6,000 Seattle City Light customers without electricity in north Seattle and Shoreline, disrupting the morning schedule for all Shoreline School District schools. Olympic Hills and Ridgecrest were among the affected neighborhoods, according to the utility’s outage map. The school district announced a two-hour delay because power outages affected multiple sites, including transportation dispatch. Seattle City Light was investigating the cause. The utility estimated power would be restored between 11:40 a.m. and noon, though that estimate could change as crews assessed the outage.