SIST EN IEC 60947-6-1:2026

Overview

SIST EN IEC 60947-6-1:2026 - "Low-voltage switchgear and controlgear – Part 6-1: Multiple function equipment – Transfer switching equipment" - establishes comprehensive requirements for transfer switching equipment (TSE) used in low-voltage power systems. This international standard ensures the continuity of electrical supply and enables effective energy management by defining how loads are safely and reliably switched between power sources. It applies to equipment with rated voltages up to 1,000 V AC or 1,500 V DC.

This fourth edition introduces technical revisions and enhancements that address the latest industry needs, improving definitions, requirements, and testing procedures to ensure higher safety and performance standards for transfer switching equipment.

Key Topics

• Scope and Purpose: Defines TSE requirements for switching loads between power sources to maintain electrical supply continuity and manage energy effectively in installations with voltages up to 1,000 V AC or 1,500 V DC.
• Types of TSE Covered:
  • Manually operated (MTSE)
  • Remotely operated (RTSE)
  • Automatic transfer switching equipment (ATSE), including integrated and stand-alone ATS controllers
  • Bypass/isolation transfer switch equipment (BTSE)
  • ATSE with closed transition capability
  • TSE for electric driven fire pump controllers
• Exclusions: Does not cover partially type-tested or non-compliant TSE, auxiliary contacts, transfer switches for explosive atmospheres, embedded software, cybersecurity aspects, specific asynchronous motor starters, multi-source/load-shedding/bus-tie/overlapping neutral TSE, and static transfer switches (see IEC 62310 series).
• Significant Technical Changes in This Edition:
  • Clarified scope and definitions
  • New and revised requirements for marking, clearances, and performance
  • Updated mechanical and electrical interlocking requirements
  • Enhanced electromagnetic compatibility (EMC) criteria
  • Additional stringent tests for DC-rated TSE and critical load current performance

Applications

The standard applies to transfer switching equipment (TSE) utilized in a broad range of industrial, commercial, and infrastructure power systems where uninterrupted electrical supply and dependable source transfer are essential, such as:

• Backup Power Systems: Ensuring seamless transition from primary to standby (generator or alternate utility) power in data centers, hospitals, manufacturing plants, and critical infrastructure.
• Energy Management: Facilitating load transfer for optimized energy use, cost savings, and reliability in building and facility management.
• Fire Pump Control: Establishing rules for TSE in fire protection systems where rapid, reliable load transfer is mission-critical.
• Automatic Transfer: Supporting automatic source switching in unmanned or remote installations for enhanced resilience and grid reliability.

Benefits include assurance of equipment performance, compliance with recognized international safety standards, reduced downtime, and alignment with best practices in low-voltage switchgear design and operation.

Related Standards

• IEC 60947-1:2020: General rules for low-voltage switchgear and controlgear
• IEC 60947-5-1: Auxiliary contact performance (for guidance)
• IEC 60947-4-1: Utilization categories and motor starter details
• IEC 60079 series: Requirements for equipment in explosive atmospheres
• IEC TR 63201: Embedded software design guidance
• IEC TS 63208: Cybersecurity for low-voltage switchgear
• IEC 60364-5-56: Safety services and emergency lighting
• IEC 62310 series: Static transfer switch requirements

Practical Value

Implementing SIST EN IEC 60947-6-1:2026 helps manufacturers, facility managers, electrical consultants, and system integrators:

• Specify and verify compliant transfer switchgear for critical power infrastructure
• Meet international safety, reliability, and operational continuity requirements
• Ensure robust performance under both normal and abnormal operating conditions
• Simplify selection and acceptance of TSE across global projects through harmonized, widely adopted specifications

Keywords: transfer switching equipment, low-voltage switchgear, controlgear, automatic transfer switch, backup power, energy management, IEC 60947-6-1, continuity of supply, safety standard.