SENTRON cylinder fuse insert, Class CC, 20 A, fast, Un AC: 600 V. Not for use within the European Economic Area (EEA), Turkey, Switzerland. UL fuse systems Class CC and Class J. The 3NW fuse system from Siemens is an important component of the SENTRON protection devices for electrical installations and provides effective protection for people, equipment, and systems through safe disconnection in overload and short-circuit situations. Class CC fuses are used for "Branch Circuit Protection" applications. Class J fuse inserts are used for "Branch Circuit Protection" and in the "Feeder Circuit." Siemens NW fuses are characterized by: 1. Facilitated export due to UL and CSA approval for typical applications in the North American market. 2. Modern design with touch protection ensures safe installation. 3. Possible fuse replacement of the fuse holders in a de-energized state. Siemens offers solutions for safe and efficient protection.