Burnt Wiring Harness

[Alaska64c10]

Its burnt up on me twice now. Its the engine wiring harness? From the firewall, to the alternator and the lights,horn,relay, and regulator. Once driving the way home , lights started going out and burnt up my relay and regulator and lights as well. I tried to make it home while I still had some light , but she died on me. Patched it up real good....Haha. I had driven it a while before that, but I recently also added an MSD ignition. I was wondering if I'm getting too much power? Do I need an inline fuse? Or is it just bad wiring? I'm going to check out another harness tomorrow, hopefully it's just bad wiring, also looking into a whole new harness. Thanks for any input!! Oh, I can post some pictures as well..!