What is the wire that goes from the positive side of the battery to the fuse box called?

Reason being is that it is getting worn and I would like to replace it, It seems important for such a thin wire, because if its not hooked to the battery the engine wont turn. It's been spliced a few times and I would just rather replace it.

 

I dont think you can buy that seperately. Its the wire that powers your fusebox. You can get a heavy gauge wire with round connectors on each end and replace it. You should be able to see where in the fuse box it attaches to

 

That wire should have a fuseable link for a section of it. That needs to be replaced with same. Possibly a inline fuse of similar amperage could also work.

For ideas and option in regards to this wire, search "Big 3 Upgrade" here on YT.

 

No fusible link between the battery and the fuse in the fuse box. That cable always seems to break near the battery cable from corrosion.