Alternator fuse

[needseats]

I have a 90 240 with ka24de out of a 93. it keeps blowing alternator fuse's...soon as i hook up the battery cable, POP, it sparks on the battery post and check my fuse and its gone...obviosly something is'nt grounded. I've read around and some guy said that if you overtighten the post that you connect one of the wires to on the back of the alternator, if will cuase a short inside of the alternator...i took off the alternator and I could wiggle that post...i went to get it tested at autozone and it passed...not sure if it passed cuase the kid really had no idea what he was doing, he did a wire check and it said passed, since i been there already an hour i said F#$K it.. anyways anyone have any idea why these keep blowing...these little bastards are 16 bux a peice at nissan. thanks.

[projectRDM]

Blowing a fuse has nothing to do with the ground, the issue is the power wire IS grounded to the case.

Unbolt the lead wire and see if the fuse blows, if not then you've broken the insulator on the case, replace it.

[needseats]

sorry what exactly is the lead wire? and replace the insulator...sorry kinda confused.

[projectRDM]

Large 6guage wire that feeds the fusebox, remove it, try a new fuse. If it doesn't blow, check the insulator. The insulator is a black plastic ring that sits underneath where the lead wire bolts to the case. If it's cracked or broken the stud that the lead wire attaches to will contact the case, grounding the lead to the chassis.