The DC-FA-100 100 Amp fuse is required to prevent damage if there is a short circuit along the length of the cables that connect the battery to the Samlex Solar RV power inverter. Thousands of amperes of current can flow from the battery to the point of shorting and that section of the cable will overheat, the insulation will melt and the cable will ultimately break. To prevent occurrence of hazardous conditions under short circuit conditions, an appropriate fuse should be used in the battery circuit that has the required current interrupting capacity. .. see full description