Fusible link guage?

I tend to agree with Cudamark. I have never had a bad ammeter on any of my cars. I'd look elsewhere. If your wires were loose you wouldn't pull more current, you'd pull less and that does not explain why you burned up the fuse link. You had to be pulling a ton of current for it to blow which means something is shorting to ground. You may want to reach up under the dash and wiggle things around to see if you can recreate the problem before you drive it down the road. Put an ammeter in series with your battery and have someone monitor it while you do this or you can just use the ole lightbulb trick as described above.