RCBOs offer protection for people and property as well as protection against electrically ignited fires in accordance with DIN VDE 0100-410 and DIN VDE 0100-530. The RCBOs in the DS250N-UC series ensure protection against sinusoidal alternating currents, pulsating currents to earth and smooth DC residual currents with a wide range of (high/)frequencies. As well as fault protection (protection against indirect contact), additional protection (with I¿n = 30 mA) and protection against electrically ignited fires (with I¿n = 300 mA). They meet the product standards for type A DIN EN 61009-1 (VDE 0664-20) appendix G and type B DIN EN 60947-2 (VDE 0660-101).
The DS250N-UC series are special FI/LS combinations for use in DC local transport railways, particularly in the overhead line area. They were developed based on the above product standards and correspond exactly to the recommendations of VDV document 509 (10/08): 'Use of residual current (FI) protective circuits in electrical power systems of DC local transport railways'.
The DS250N-UC consists of an all-current sensitive FI block (type B) and an LS part with one or three outer conductor poles in AC design and two oppositely connected neutral conductor poles in UC design - for the polarity-independent shutdown of direct currents (N-UC: N pole for universal current).
This means that the high compensating direct currents between the neutral conductor of the general network and the DC earth (the return conductor of the DC railway network) - or vice versa - can be safely switched off.