SENTRON, cylindrical fuse holder, 14x51 mm, 3-pole, In: 50 A, Un AC: 690 V SENTRON cylindrical fuse system for selective system protection. Siemens cylindrical fuse inserts and fuse holders are suitable for use in industrial systems. They are standard in Europe and tested and approved as fuse disconnectors but are not intended for switching under load. Siemens offers an extensive portfolio for switching under load, e.g. 3KF. The Siemens cylindrical fuse systems are characterized above all by: 1. Compliance with the standards IEC 60269-1, -2 and -3. 2. Compliance with the standard UL 512. 3. Fast fuse replacement thanks to space for spare fuses in the drawer. 4. Fast detection of the blown fuse thanks to a flashing LED in the event of a blow.