IEC 60947-6-1 Ed. 4.0 b:2026

IEC 60947-6-1:2026 is available as IEC 60947-6-1:2026 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.

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.