In Paraguay, all homes have a floating neutral that is sometimes connected to the utility's "ground," but not always. They use 23 kV delta, with a small neutral at the top for lightning and drain on shielded cables. Most homes have three phase 380/220 50 Hz, with the exception of small shacks, where a single phase service up to 40 A is provided (the limits without special approval are 10 kW for single phase and 30 kW for three phase based on 220 V). 220 V is the regulation, but they are always 400/231 transformers being used.
However, large buildings like apartment buildings and malls, where there are many separate meters (which measure neutral, by the way -- four wires in and four out), have a proper TN-S system. A little icon on the LCD comes on if any neutral current was bypassing through the meter somehow (e.g. to the communal ground if it exists or leaking to a neighbor's connection).
The risk is mitigated by installing a 30 mA RCD in newer homes, but in old homes, your bets are off.
