A construction mishap at Churchill Downs on Wednesday afternoon caused a power outage that briefly interrupted wagering on races at Ellis Park, its sister track in Henderson, Ky., and left most of the historic racetrack and its offices in the dark for a time.The outage occurred around 2:15 p.m. (EDT) when a steel work crew that was dismantling the track's grandstand roof accidentally cut into a live power junction box. The mishap disabled the track's electrical, phone and computer systems.The disruption of power briefly affected the wagering hub located at on its grounds. The hub processes wagers placed at most racetracks and off-track betting outlets in Kentucky--including Ellis Park, which is now conducting its live meet. The track had completed its first race when the outage occurred. Wagering at Ellis Park and simulcast wagering on the track's races was interrupted for approximately 35 minutes until a backup generator at Churchill Downs restored power to the wagering hub system. Racing resumed at Ellis Park at approximately 3:10 p.m. (2:10 p.m. CDT in Henderson).Full power was restored at Churchill Downs at approximately 3:30 p.m.The roof work is part of the $27 million phase I of the Churchill Downs renovation project.