Residual current circuit breakers (RCCB) switch off the power supply when dangerously high residual currents occur. In this way, they protect people, animals and systems. DFS 2 are two-pole residual current circuit breakers for single-phase networks. In the standard version, the compact devices are two division units wide. They are available with many different residual current types and versions with rated currents of up to 125 A. The large double-deck terminals can also accommodate large conductor cross-sections. The tripped position of the multi-function switch toggle makes troubleshooting easier. The free label software helps with labeling. Type B+ residual current circuit breakers are sensitive to all currents. They protect against pulse and alternating residual currents, residual currents with mixed frequencies and smooth direct residual currents. They detect residual currents of all frequencies up to 20 kHz with a maximum tripping threshold of 420 mA. The switches therefore offer a high level of fire protection. Standard devices are designed for monitoring circuits with a rated voltage of 230 V and a rated frequency of 50 Hz. Properties: universally sensitive for residual currents with frequencies and mixed frequencies from 0 Hz (smooth direct current) to 20 kHz, fire protection in accordance with VDE 0100-420, mains voltage-independent tripping for type A residual currents, voltage-dependent detection of smooth direct residual currents and alternating residual currents with frequencies not equal to 50 Hz, full functionality with mains voltages from at least 50 V AC on any two active conductors, small size for all rated currents, high short-circuit strength, double-sided double-deck terminals for large conductor cross-sections and rail connection, switch position indicator, viewing window for labels, multi-function switch toggle with three positions: 'on', 'off', 'tripped', connection C1 neutral conductor position as desired, mounting type: quick fastening on mounting rail, installation position as desired, feed preferably from above, areas of application: commercial and industrial installations with TN-S, TT and TN-CS systems, in which power electronics equipment is used without galvanic mains isolation, such as frequency converters, switching power supplies, high-frequency converters. Photovoltaic and UPS systems with transformerless inverters. Fire-hazardous operating locations. Notes: suitable for use in 50 Hz alternating current networks. RCCB for other frequencies on request. Not intended for use in direct current networks or on the output side of controlled electrical equipment such as frequency converters.