The power outage in North Hall County on Saturday night remains under investigation, said Craig Heighton, public affairs director for Georgia Transmission Corp. A piece of equipment called a swivel that was holding up a section of power line failed in an area off Sardis Church Road, allowing the line to sag into another power line, breaking some poles and plunging the area into darkness, Heighton said. “This was a very, extremely rare incident,” Heighton said.