My car has a "blown" fuse and I was told there may be a "short circuit"? What does any of this mean and what is a "short circuit"? Sometimes the terminology that is used in an industry can be confusing and daunting. A fuse is a circuit protection device that has a specific rating, when this amperage rating is exceeded the fuse material melts creating an open circuit and what is what is referred to as a "blown" fuse. Anything that creates amperage draw in excess of the fuse rating will result in a blown fuse. A short circuit is when the electrical flow in a circuit takes an unintended path back to ground. The lack of resistance in the unintended path creates a dramatic spike in amperage and leads to a blown fuse. In the picture above the chaffed wire rubbed against a grounded chassis point creating a short circuit and a blown fuse.