FI/LS switch, 6 kA, 3P Type A, 300 mA, C-Characteristic, In: 16 A Un: 400 V. SENTRON 5SU1 FI/LS switch for combined protection against overload, short circuits, and fault currents. Our FI/LS switches (RCBO) are VDE tested and certified according to DIN EN 61009-1, DIN EN 61009-2-1. With their double chamber terminals, connecting conductors of different cross-sections is very easy. Other Siemens SENTRON protective devices can be quickly and easily connected using the 5ST3 busbars. The data matrix code on the device provides quick access to all technical data in the Siemens Industry Online Support App. SENTRON protective devices can be expanded with a wide range of functions using the continuous accessories from the system modular kit. Optimal technology for your safety - only from Siemens.