It would depend how you go about doing the big three that would depend if there was a "chance" for fire(If ever) and it's only one wire the lead from the positive output of the alternator to the positive output on the battery the stock runs a fuse, I assume it's in case there where a short or the voltage regulator stopped working and attempted to overcharge the battery so running a fuse is advised, But on the other hand when I first did the big three years ago I added a fuse on that main hot lead and had no noticeable gain in voltage when I went at the whole system ohm load testing it all I ran into one big ohm load the fuse I had installed when I removed it and ran a new solid lead everything was remarkably better. So to answer the question yes are can make anything slightly less safe by defeating a factory safety the question is is the risk worth the reward? It was for me.