Nissan Repair: 75A breaker fuse, 200sx, engine swap

Question
ok i swapped engines in a 98 200sx nissan 1.6L so when i hooked everything up engine works good. the cab wasnt turning on i mean nothing. no ac no radio, dash wasnt workin. so i checked fuses, starter, alternator, and inside fuses. nothing. then Von told me to check the breaker fuse and the 75A fuse was busted. now i called a place to get a new one and they told me that if something popped a 75A then something is really wrong as far as electrical. is this true or could it b from swapping engines? what triggers the fuse to break.

Answer
Hi Scott -

Fuses blow when there is a direct short to ground, meaning when any cable that is "hot" or attached in any way to the positive side of the battery touches any part of the engine frame or engine block.

This fuse is a substantial fuse, and that is correct, it takes a lot to blow it.

However, there is a good chance that it was blown during the engine swap.

So, I would get another fuse, replace it and see if it blows. If yes, then you will have to look for the short in your wiring.

Hope this helps -
aloha
calvin