I blew a fuse and my car died. I replaced the fuse (30A) and the car was fine. Drove about 15 miles and it blew again. What the hell is it?

Earlier that day, I replaced my alternator drivebelt. Apparently one of the bolts broke on the alt, it became loose and the belt broke off. I replaced the belt and the bolt, but I didn't use the stock bolt. I used a thinner, longer bolt. I was thinking something is touching the bolt causing the fuse to blow, but I can't see anything.

So anyone know why my ignition switch fuse is blowing? Could it be something I did to the alt or starter related?

Thanks

 

Just a theory, but when the belt broke maybe a small piece of it lodged into the alternator and is shorting out somewhere inside there.