Mersen fast acting/class T fuse. These small dimension fuses are the right fit for a tight fit fast-acting A3T class T fuses combine two highly desirable features - high current limitation and a small physical size. Their unique dimensions prevent the substitution of other fuses with lower voltage ratings or current-limiting capability. These fuses have glass melamine bodies for superior dimensional stability and catalog numbers stamped into the blades for permanent identification. Application: loadcenters, panelboards, switchboards, circuit breakers, metering centers. Approvals: UL listed to standard 248-15 file E2137, CSA certified to standard C22.2 no. 248.15, DC listed to UL standard 248.