The standard mandates a changeover device (transfer switch) for installations with both a generator and a normal supply. This device must ensure that the generator and the public supply cannot be connected simultaneously unless specific parallel operation conditions are met and authorized by the distribution network operator (DNO).
If “Part 551” actually refers to low-voltage generating sets (standby power), that is IEC 60364-5-55 (Clause 551 – Low-voltage generating sets). Check:
| True Standard | Clause | Subject | |---------------|--------|---------| | IEC 60364-5-51 | 551 | Switchgear & controlgear selection | | IEC 60364-5-55 | 551 | Low-voltage generating sets (e.g., generators) | | IEC 60364-4-41 | – | Protection against electric shock | | IEC 60364-4-43 | – | Overcurrent protection | iec 60364 part 551 pdf
IEC 60364 is the international standard for electrical installations in buildings. Part 5-551 specifically addresses "Selection and erection of electrical equipment – Low-voltage generating sets."
While earlier parts of the standard deal with general protection against electric shock, Part 551 focuses on the specific hazards and operational requirements introduced when a building has its own power source. It covers generating sets that are: The standard mandates a changeover device (transfer switch)
When designing to the standard, engineers must ensure:
IEC 60364 series provides international principles; many countries adopt its parts with national modifications (e.g., HD/NEC/BSI adaptations). National regulations may add or change requirements (earthing arrangements, RCD use, specific volt-drop limits). IEC 60364 is the international standard for electrical
The next amendment to IEC 60364 part 551 (expected around 2026) will address:
Thus, obtaining the current PDF is not just for today’s compliance – it prepares you for the evolution of distributed energy resources.
IEC standards are copyrighted; obtain the official IEC 60364-5-51 PDF through: