In welcher Stadt leben sie? Entschuldigung, aber mein Deutsch ist sehr schlecht
I am not an expert, but I did have to replace some of my wiring as well because of it's poor condition, and this included the positive battery cable. As for the fusible links, I eliminated them based on the fact that someone told me it was ok to do so. You can, I believe, replace them with in-line fuses of the appropriate rating. Also, you should be able to reduce the temperature of the wire in question by replacing it with a large gauge wire, since that will reduce the resistance.
Perhaps if the wire is getting that hot, there is a problem in the circuit?