CHARLESTON, W.Va. -- Thieves took an extensive amount of copper ground wiring from a Kanawha City power substation early Thursday, knocking out service to nearly 3,000 people, power company officials said.Customers lost electricity when the theft occurred at Appalachian Power's Chesterfield Avenue substation at about 4:40 a.m., APCO spokeswoman Jeri Matheney said. Power crews were alerted to the theft when a voltage alarm went off at the substation."Someone was dispatched immediately to go investigate and, of course, it took a while to survey all the damage and to discover it was a very comprehensive theft," Matheney said.Power crews shut off all current to the substation to assess and repair damages. All power was restored by 1 p.m., according to APCO's website.Matheney said it must have taken the suspect or suspects several hours to remove nearly all the copper ground wiring.A substation moves large amounts of electricity coming from a power plant across large distances and into neighborhoods. That particular substation is one of APCO's largest, serving thousands of customers and businesses in Kanawha City along MacCorkle Avenue and in South Hills along Bridge and Loudon Heights roads.Power was knocked out to CAMC Memorial Hospital in Kanawha City for a short while, requiring the staff to run on backup generators, Matheney said. All traffic lights were out in Kanawha City from 31st Street and MacCorkle Avenue to South Ruffner Road, according to Kanawha County Metro 911 dispatchers.Power also was knocked out at the University of Charleston, forcing school officials to cancel all classes until about 11 a.m.Matheney said the theft endangered the thief, power crews and the customers served by the substation.APCO urged anyone with information about the thefts to call its confidential hotline, 1-866-747-5845, or the police. A reward of up to $5,000 has been offered for information leading to an arrest and conviction.Reach Travis Crum at email@example.com or 304-348-5163.