What may be important in this setup is. (PE protective earth)
The cable from the transformer has a common N and PE (TNC)
From the main panel, the N and the PE are splitted, so the rest of the building are TNS. The PE are bonded to pipes, and other metallic parts of the building where so are. N are never grounded after the main panel. N are deemed to be treated as a live wire, and all circuit breakers are multipole, and senses current in, and breakes N to.
In this building all branches are protected with combined GFCI and breakers. All light switches breaks both live and renewal to bathrooms etc. We still use Schuko and they are unpolarized. The North American AFCI are not used at all here.
Great info.
TN-C should be avoided anywhere in the system for a variety of reasons. Yes it is commonly used in Europe and USA, but has downfalls. Some of the current flows through the earth producing elevated magnetic fields and step touch potentials (stray voltage)
An example:
https://s855.photobucket.com/user/mbrooke22/media/jord_zpsfd497037.jpg.html
