High Protective-Conductor-Current Equipment — Fixed Connection Required

Electrical equipment (such as large variable frequency drives, IT server racks with many switch-mode power supplies, or medical imaging equipment) whose normal, operational protective-conductor current (leakage current to earth via the PE conductor) exceeds 10 mA per IEC 60364-5-54 §543.7. Such equipment is subject to additional requirements: either a PE conductor with a minimum cross-section of 10 mm² copper (or an equivalent duplicated PE conductor, each with the normal minimum cross-section and its own independent terminal), or automatic disconnection upon interruption of the PE conductor, or a fixed connection (no plug-and-socket connection) so that the continuity of the earth connection does not depend on an easily disconnectable connector. The purpose is to prevent someone touching the metal enclosure during operation from experiencing a touch current that, although below the hazard threshold, would be perceived as unpleasant or alarming if the PE were accidentally interrupted.