FI/LS switches (RCBOs) provide personal and property protection as well as protection against electrically ignited fires in accordance with DIN VDE 0100-410 and DIN VDE 0100-530. They ensure the protection of three single-phase or three-phase circuits against overload and short-circuit currents, protection for sinusoidal alternating currents and pulsating currents with smooth residual direct fault currents of up to 6 mA to earth. Additionally, they offer fault protection (protection against indirect contact), additional protection (with IΔn ≤ 30 mA), and fire protection (with I∆n ≤ 300 mA). They comply with the product standard IEC/EN 61009-1 (VDE 0664-20). Applications include household, commercial, and industrial uses. The extensive range of accessories provides everything you need for your installation tasks. Numerous approvals make the DS203NC suitable for worldwide use. The rated breaking capacity Icn is 6,000 A according to IEC/EN 61009-1 (VDE 0664-20) for RCDs (residual current devices) in residential construction and similar applications, Icu = 10 kA according to IEC/EN 60947-2 (VDE 0660-101) for MCBs (LS) in industrial applications. The RCBO DS203NC Type A is 3-pole protected (LS), 4-pole switching, and can be used in three-phase networks with or without a neutral conductor. Type A AP-R offers an optimal compromise between safety and operational continuity thanks to its robustness against surge currents (surge current waveform 8/20 μs) = 3,000 A against unwanted tripping and a 10 ms short-time delay.