Overview
IEC 60947-2:2024 is the sixth edition of the international standard governing low-voltage switchgear and controlgear, specifically focusing on circuit-breakers. Published by the International Electrotechnical Commission (IEC), this standard applies to circuit-breakers intended for installation and operation by instructed or skilled persons. It covers main contacts intended for circuits with rated voltages up to 1,000 V AC or 1,500 V DC. Additionally, it includes requirements for integrally fused circuit-breakers and circuit-breakers with ratings above 1,000 V AC but not exceeding 1,500 V AC.
This edition replaces the 2016 version and its 2019 amendment, incorporating significant technical updates to ensure safety, reliability, and performance in modern electrical installations.
Key Topics
- Scope & Application: Circuit-breakers with rated voltages up to 1,000 V AC/1,500 V DC, used by skilled persons for protection and control of electrical circuits.
- Technical Revisions & Updates:
- Suitability for isolation and removal of obsolete classifications.
- Updated current settings with external devices connection for overcurrent releases.
- Enhanced requirements for circuits with protective separation.
- Additional tests for ground-fault overcurrent releases and dielectric properties in the tripped position.
- Use of DC voltage in dielectric testing.
- Tests on individual pole breaking capacity under phase-to-neutral AC voltage.
- Improved measurement methods for power loss.
- Changes in electromagnetic compatibility (EMC) testing.
- Introduction of a new circuit-breaker interrupting (CBI) classification – Class W.
- Construction & Performance: Detailed constructional requirements, including safety, clearances, creepage distances, and digital I/O compatibility for PLCs.
- Test Procedures: Comprehensive testing sequences including mechanical operation, dielectric strength, short-circuit breaking capacity, and special conditions such as damp heat, salt mist, vibration, and shock.
- Additional Features:
- Integration of integral fuses within circuit-breakers.
- Coordination considerations between circuit-breakers and other short-circuit protective devices.
- Specific provisions for circuit-breakers incorporating residual current protection (CBRs).
Applications
IEC 60947-2:2024 is essential for manufacturers, designers, and installers of low-voltage electrical distribution and control systems. Its practical applications include:
- Industrial Electrical Panels: Ensuring reliable operation and safety of motor control centers, switchboards, and distribution panels.
- Building Installations: Protecting lighting, heating, and power circuits in commercial and residential buildings.
- Renewable Energy Systems: Circuit-breakers designed to cope with DC voltages up to 1,500 V for photovoltaic and battery energy storage systems.
- Protective Coordination: Improving selectivity and coordination between protective devices to minimize downtime and enhance system reliability.
- Automation & Control: Integration with programmable logic controllers (PLCs) through standardized digital inputs and outputs for smart control and monitoring.
- Safety Compliance: Ensuring installations comply with international safety requirements for low-voltage circuit protection against overloads, short circuits, and ground faults.
Related Standards
- IEC 60947-1: General rules for low-voltage switchgear and controlgear - provides foundational requirements referenced in IEC 60947-2 for construction, safety, and testing.
- IEC 60947-3: Switches, disconnectors, switch-disconnectors, and fuse-combination units - complementary for related devices often used alongside circuit-breakers.
- IEC 61009: Residual current operated circuit-breakers with integral overcurrent protection (RCBOs) - for detailed requirements specific to devices with residual current protection, complementing the CBR provisions in IEC 60947-2.
- IEC 60269: Low-voltage fuses - integrating fuse technologies for protection coordination with integrally fused circuit-breakers.
- IEC 61000 Series: Electromagnetic compatibility (EMC) standards - addressing EMC testing methods referenced in the amended EMC test requirements.
By adhering to IEC 60947-2:2024, manufacturers and users gain confidence in the safety, reliability, and interoperability of low-voltage circuit-breakers tailored to modern electrical systems. This standard serves as a cornerstone in electrical engineering, ensuring protection, performance, and compliance in diverse low-voltage installations worldwide.
