Redundancy is good except ...

       

Always make sure there is one and only one conductive connection between the N conductor and the PA/PE system within a TN-S installation, even when there are several star points from several sources feeding into the system!

Otherwise the beneficial effects of a TN-S system are largely made void. In this case, the connection from the transformer star point to the central earthing bar bears a current of 25A (in addition to the regular neutral conductor current - the neutral conductor is not connected to the earthing bar but directly to the transformer star point, so this share of the current is not measured at this point here). The reason is that this is not the central earthing bar. Rather, there are 3 transformers feeding in parallel, with each transformer cubicle having its own earthing bar and each star point being earthed there individually.

This allows a part of the neutral current to take the route across the earthing system along the PE and PA conductors and all earthed metallic structures which are not meant to be electrical conductors (which experts call "extraneous conductive parts"). This usually leads to disturbances in the data transmission system of the affected building and to hardware damages of data equipment.