I used to think the main job of a fuse is to protect against a short but I'm starting to think it is to protect from a constant overload. My reasoning is that if there is a short than this creates a massive current in an instant and regardless of the fuse size it is likely to blow straight away to prevent further damage. Whereas a fault that causes a largish current draw will eventually melt cables/start fire unless the fuse blows. Is this theory sound or am I off track. I know it protects from both but is the fuse size less important for a short.