Choice of earthing systems and conclusion
The three earthing systems used world-wide and standardised by IEC 364 have as their common goal the search for enhanced safety.
Regarding protection of people, all 3 earthing systems are equivalent provided that installation and operation rules are complied with.
Given the characteristics specific to each earthing system, a systematic choice each time is not possible.
The choice must result from discussion between the user and the network designer (contractor engineering and design department, etc.) concerning:
The installation characteristics;
The operating conditions and requirements.
It is an illusion to want to operate an unearthed neutral network in part of an installation that, by nature, has a low insulation level (a few thousand ohms); old, extensive installations with external lines...
Likewise, it would be contradictory, in an industry in which continuity of supply or productivity is a prime requirement and in which the fire hazard is great, to choose a neutral connection system.
