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First of all, such wiring is only possible using a TN electrical system. With an IT system, it is not possible to connect the charging station without the neutral wire.

For the TN systemThe neutral conductor (N-conductor) is present in the TN-S, TN-C-S, and TT distribution systems. In a TN-C distribution system, however, the N-conductor is combined with PE (ground) in the so-called PEN conductor. IT systems do not have an N-conductor, so the problem is in the IT distribution system itself.

If connecting an INCH charging station to a distribution system without an N- or PEN conductor, the solution is to install a Dyn transformer (Delta to wye windings with neutral point) or to ground the N-terminal of the stations. NoteIf this is done incorrectly or if the IT system 3-phase transformer (Dyn or Yyn), which would provide the point of the N-conductor.

If the load of the INCH (AD/DC converter in the car) is a single-phase, a 1-phase transformer with a voltage ratio of Np : Ns =  1.739 * can be used to reduce the phase-to-phase voltage from 400 V to 230 V, where one of the phases is earthed and connected to the N-terminal. This solution would be cheaper; however, we must ensure that the connection is always 1-phase.

* Np is the number of turns of the primary winding and Ns is the number of turns of the secondary winding on the transformer.