James,
Since there seems to be big interest in the nuclear electromagnetic pulse (EMP) effect, SurvivalBlog readers might want to see some footage about the Starfish Prime [1] test, [a part of Operation Dominic, a series of tests intended to test nuclear weapons effects in space], which knocked out some power substations on Oahu, Hawaii, around 800 miles away back in 1962. Video clip 1 [2]. Video clip 2 [3]. – David in Israel