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12.11.2014

E-mobility: Residual current protection without compromise

Doepke's DFS 4 EV for charging stations makes retro-fitting the building installation superfluous


Norden, March 2014. Innovation at the Light + Building: Doepke has developed the DFS 4 EV residual current circuit-breaker especially for protection during the charging of electric vehicles. It provides a compromise-free solution and is designed to be installed into charge columns and wall boxes.

It must be used there if the upstream residual current protection is not recognised or has been provided by an RCD of Type AC, A or F. The smooth DC residual currents caused by faults in the charging equipment can affect the above-mentioned RCDs so much that they can no longer fulfil their intended protective function. As a result of their 'blinding', hazards to the person and property can be expected. In accordance with DIN VDE 0100-720, a residual current operated protective device with a rated residual current of less than or equal to 30 mA must be used for each individual connection point. Measures must also be taken to ensure protection in the case of smooth DC residual currents that are higher than 6 mA. The DFS 4 EV detects sinusoidal AC currents as well as pulsating DC residual currents. The active additional function for detecting smooth DC residual currents of max. 6 mA is maintained by the upstream residual current operated protective device even if, for example, DC residual currents are caused by the charging equipment. In this way the DFS 4 EV ensures reliable personal and fire protection for the downstream charging socket as well as the upstream RCD. Depending on the construction of the e-mobility supply unit, the device is either fitted as standard by the manufacturer of the charging infrastructure or retro-fitted by a qualified specialist electrician. The DFS 4 EV simplifies the standard-compliant, safe installation of charging equipment, irrespective of whether the charging equipment is operated from an available electrical socket or is installed by a qualified specialist electrician.

The DFS 4 EV is available in two variants in the 4-TE housing; the two pole version is suitable for rated currents up to 25 A, the four pole version up to 40 A.