Staff Sgt. Joel Nobles, 28th Bomb Wing Staff ground safety technician, uses a polarity tester to ensure outlets will trip when necessary at Ellsworth Air Force Base, S.D., Nov. 29, 2012. The 28th Bomb Wing ground safety personnel perform unannounced spot inspections randomly among the wing once a week to ensure sections are in compliance with safety regulations. (U.S. Air Force photo by Airman 1st Class Alystria Maurer/Released)