Abstract: The disclosed fuse has a tube of insulation, terminals at the ends of the tube, a link connecting the terminals, and a granular filler. At least one end cap is made of sheet metal which has one or more integrally extending tabs and a respective hole for each tab, each tab and its hole having the same size and shape. Granular fill is introduced via said hole(s) while the tab(s) are raised to provide wide openings. The end cap is sealed by driving the tab(s) into the hole(s). After the fuse contains granular filler but before driving the tab(s) into the hole(s), the fuse may be impregnated with a fluid, first adjusting the tab(s) to be narrowly open to retain the granular filler while admitting the impregnant.