IEC 60947-6-1:2026

IEC 60947-6-1:2026 applies to transfer switching equipment (TSE), to be used in power systems for ensuring the continuity of the supply and allowing the energy management of the installation, by transferring a load between power supply sources, the rated voltage of which does not exceed 1 000 V AC or 1 500 V DC. Specific requirements for bypass/isolation transfer switch equipment are given in Annex C, ATSE having closed transition capability are given in Annex D, stand-alone ATS controllers are given in Annex E, and TSE for electric driven fire pump controllers are given in Annex F.
It covers:
- manually operated transfer switching equipment (MTSE);
- remotely operated transfer switching equipment (RTSE);
- automatic transfer switching equipment (ATSE), including the controller;
- stand-alone ATS controllers;
- bypass/isolation transfer switch equipment (BTSE);
- ATSE having closed transition capability;
- fire pump TSE.
It does not cover:
- TSE configurations that are not fully manufacturer type tested or marked according to this document as a complete transfer switch;
- auxiliary contacts (for guidance, see IEC 60947-5-1);
- transfer switches used in explosive atmospheres (for guidance, see IEC 60079 (all parts));
- embedded software design (for guidance, see IEC TR 63201);
- cybersecurity aspects (for guidance, see IEC 63208);
- TSE rated for direct-on-line starting asynchronous motor of design NE and HE, according to IEC 60034-12. (for guidance, see AC-3e utilisation category according to IEC 60947 4 1);
- other types of TSE under consideration including overlapping neutral TSE, multi-source TSE (i.e. TSE with more than two sources of supply), TSE with load-shedding functions, bus-tie TSE, and hybrid TSE;
- static transfer switches covered by IEC 62310 series.
This fourth edition cancels and replaces the third edition published in 2021. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
- clarification of scope;
- clarification of terms and definitions;
- Annex C for Bypass/Isolation Transfer Switch Equipment;
- Annex D for ATSE having closed transition capability;
- Annex E for Stand-alone ATS controller;
- Annex F for TSE used with electric driven fire pump control equipment.