alternator fuse keeps blowing.........

i have a 2000 civic si, and everytime i go to crank the car the alternator fuse blows. i have not had the alternator tested but would a bad alt make the fuse blow before the car was running. i turn the key and when i get to the last acc before the start the fuse blows. no work has been done to the cars electrical system. i am stumped. does anyone have any ideas. again this is the stock alt. so could a bad alt make a fuse blow, please i need some help....thanks..by the way the battery is fine and the grounds are good...