Jesus Serna works on the assembly line at Generac Power Systems Inc., one of the largest makers of residential generators in the United States, in Whitewater, Wis., on Friday, Nov. 16, 2012. (AP Photo/Nam Y. Huh)

Photo by: Nam Y. Huh

Jesus Serna works on the assembly line at Generac Power Systems Inc., one of the largest makers of residential generators in the United States, in Whitewater, Wis., on Friday, Nov. 16, 2012. (AP Photo/Nam Y. Huh)