5kV ** FERRULE MOUNTED FUSES Amp-trap CS-3 E-rated 5kV, 8kV and 15kV fuses have 2 or 3 Inch diameter barrels with ferrules and are mounted in spring reinforced clips. They are UL listed as "general purpose current-limiting fuses" and are for use indoors (or outdoors in a weatherproof enclosure). The unique time-current characteristic of Ferraz Shawmut E-rated fuses allows them to be closely sized to transformer full-load rated current, as recommended by IEEE guidelines, without being affected by normal magnetizing inrush current. CS-3 fuses are typically sized at transformer rated current of 133%, thereby providing superior overall protection.