Electrician was replacing a battery plug when a rock measuring 5'x3'x3 1/2"" fell from the roof striking him on the back of head & neck area. He drove himself to Raleigh General and the doctors gave him a full release. He returned to work & continued to work until 9/27/2011. He went to his doctor who gave him two days off with muscle relaxers. He returned to full duty on 9/30/2011.