IEC 61643-11:2025

Overview

IEC 61643-11:2025 is an international standard developed by the International Electrotechnical Commission (IEC) that specifies the requirements and test methods for low-voltage surge protective devices (SPDs) connected to AC low-voltage power systems. This standard covers devices designed to protect electrical systems and equipment rated up to 1,000 V RMS and primarily focused on 50/60 Hz power frequencies, although other frequencies are not excluded.

The standard addresses surge protection against both direct lightning strikes and indirect transient overvoltages, ensuring SPDs effectively limit surge voltages and divert surge currents using at least one nonlinear component. IEC 61643-11:2025 provides comprehensive benchmarks for performance, safety, and environmental resilience, making it crucial for manufacturers, testers, and users of surge protection devices.

Key Topics

• Scope and Application
  Applies to surge protective devices connected to AC power circuits up to 1,000 V RMS, suitable for 50/60 Hz frequencies. It includes provisions for railway applications when specific product standards are unavailable.

• Classification and Marking
  Defines key terms, device classifications, and mandatory markings, including what information must remain visible after installation. Manufacturers are required to provide detailed product information for testing and certification.

• Performance and Safety Requirements
  Covers electrical and environmental demands such as behaviour under temporary overvoltages (TOVs), dedicated overstress scenarios, ageing under damp heat conditions, and compatibility with various power sources and circuit types.

• Test Methods
  Specifies type testing procedures including electrical tests, short-circuit current behaviour, protective conductor current, thermal protection, and environmental durability. These tests validate device reliability under various fault and stress conditions.

• Coordination With IEC 61643-01
  This part supplements and modifies general SPD requirements found in IEC 61643-01. Users must apply this standard in conjunction with the latest edition of IEC 61643-01 for full compliance.

• Technical Updates in 2025 Edition
  The latest edition introduces specific AC application requirements, improvements in test coverage for internal disconnectors, additional clearance and dielectric testing for separated circuits, and enhanced measurement protocols on combined protection modes.

Applications

• Electrical and Electronic Equipment Protection
  SPDs compliant with IEC 61643-11:2025 protect low-voltage AC power systems from damaging overvoltages caused by lightning or switching operations, ensuring equipment longevity and minimizing downtime.

• Building and Industrial Installations
  Installed in residential, commercial, and industrial electrical panels to safeguard sensitive devices and infrastructure from transient surges.

• Railway and Specialized Power Systems
  Applicable to railway power installations and other specialized environments lacking dedicated surge protection standards, subject to risk assessment.

• Utility and Renewable Energy Systems
  SPDs tested against this standard help maintain system stability by mitigating surge-induced faults in low-voltage distribution networks, including solar inverters and battery storage systems.

Related Standards

• IEC 61643-01
  Specifies common requirements and tests for all surge protective devices; IEC 61643-11 supplements and modifies these requirements specifically for devices connected to AC low-voltage power systems.

• IEC 60364-4-44:2024
  Provides guidelines on temporary overvoltage (TOV) ratings and testing relevant to SPDs in low-voltage electrical installations.

• IEC Guide 116
  Offers guidance on risk assessment methodologies applicable to determining the extent of testing and requirements for SPDs under specific conditions.

This standard is essential for ensuring that low-voltage AC surge protective devices meet rigorous international safety and performance benchmarks, safeguarding electrical installations against transient overvoltages while optimizing device reliability and operational safety. Manufacturers and end-users should integrate IEC 61643-11:2025 within their quality assurance and compliance strategies to provide effective surge protection aligned with global best practices.