EZ wire alt wire

Depends on how you are running the charge line on your car. How is the charge from alternator getting back to your battery? Are you running an ammeter and want to keep it?

I'd run a direct line from alternator to starter relay, then buss things from that location.

The fusebox likely is a deadhead of sorts. It will grab energy from a location and isn't an in series piece, that will allow for the charge to pass through to the battery. Just a guess.