An employee was on the 7-10 Service Cage headed down into the mine, when at about 170 feet from the top, the switch gear at the mine 7 east sub-station went phase to phase causing the cage to stop from loss of power. The employee was not injured and was entrapped on the cage from 4:30 p.m. until 6:50 p.m. when power was restored and the employee was hoisted to the surface.