Auxiliary current switch 1 CO for cylindrical fuse holder Sz. 10 x 38 mm/8 x 32 mm SENTRON cylindrical fuse system for selective line protection. Siemens cylindrical fuse-links and fuse holders are suitable for use in industrial plants. They are standard in Europe and are tested and approved as fuse disconnectors, but not for switching under load. For load switching, Siemens offers an extensive portfolio of products, e.g. 3KF. The Siemens cylindrical fuse systems are characterized primarily by: 1. Compliance with the standards IEC 60269-1, -2 and -3. 2. Compliance with the standard UL 512. 3. Fast fuse change due to space for spare fuses in the slide-in unit. 4. Fast detection of a tripped fuse due to LED that flashes when the fuse trips.