Overview
IEC 60947-2:2016/AMD1:2019 is an important amendment to the international standard covering low-voltage switchgear and controlgear, specifically Part 2: Circuit-breakers. Issued by the International Electrotechnical Commission (IEC), this amendment refines and updates requirements for low-voltage circuit-breakers with rated voltages up to 1,000 V alternating current (a.c.) and 1,500 V direct current (d.c.). It also includes additional clauses for integrally fused circuit-breakers to enhance safety, reliability, and performance.
This standard targets manufacturers, installers, and skilled technicians involved in the selection, installation, operation, and maintenance of low-voltage circuit-breakers. It ensures harmonized, globally recognized criteria that govern the design, testing, marking, and usage of circuit-breakers to meet modern electrical infrastructure demands.
Key Topics
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Scope and Application
The amendment expands the scope to emphasize circuit-breakers intended for use by trained operators. It covers aspects such as use in variable frequency drive downstream circuits, marine environments, traction systems, and explosive atmospheres requiring special considerations.
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Normative References Update
Updated references include key IEC standards like IEC 61000-4-2 for electromagnetic compatibility (EMC), IEC 61140 for protection against electric shock, and CISPR 11 and 32 for radio frequency disturbance limits. Older references to IEC 60364 and CISPR 22 have been removed to maintain relevance.
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New Definitions and Device Types
The standard introduces definitions such as "closing release," referring to auxiliary devices responsible for triggering the closing function of circuit-breakers. It also expands the classification of release types to include shunt releases, undervoltage releases, and closing releases.
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Marking Requirements
Detailed marking criteria ensure circuit-breakers carry essential operational and safety information clearly visible or marked on the device, including:
- Rated current and voltage
- Indications for isolation suitability
- Manufacturer identification and compliance with IEC 60947-2
- Rated short-circuit breaking capacities
- Terminal identification and protective earth markings
- Auxiliary device ratings and control circuit data
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Installation, Operation, and Maintenance Instructions
The amendment mandates clear user guidance, including additional information for safe decommissioning and dismantling, especially where hazardous conditions due to stored energy or materials could be present.
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Thermal and Electrical Performance Testing
Updated requirements for temperature rise limits, short-circuit testing with metallic screening, and torque application during terminal connections ensure circuit-breakers operate safely under nominal and fault conditions.
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Test Sequences and Sample Quantities
Clarifications in test sequence applicability and sample sizes enhance the reliability of conformity verification for 1-, 2-, 3-, and 4-pole circuit-breakers, taking into account selectivity categories and rated current specifications.
Applications
IEC 60947-2:2016/AMD1:2019 governs the design and use of low-voltage circuit-breakers across a diverse range of electrical systems, including:
- Industrial Installations: Protecting machinery and electrical systems in manufacturing plants with stringent operational continuity and safety requirements.
- Commercial Buildings: Ensuring safe and reliable power distribution with easy identification of manufacturers’ markings and circuit-breaker capabilities.
- Transportation: Compliance for traction systems and rolling stock requiring specialized circuit-breakers for harsh environments.
- Marine and Hazardous Environments: Application of additional safety requirements for circuit-breakers used in marine vessels and explosive atmosphere scenarios.
- Renewable Energy Systems: Protection of photovoltaic and other alternative power generation circuits within the specified voltage ranges.
- Variable Frequency Drives: Addressing downstream protection needs of motor drive systems with distinct electrical characteristics.
The standardized approach helps manufacturers align product development with international safety and performance criteria, supporting easier market access and compliance verification.
Related Standards
- IEC 60947-1: General rules for low-voltage switchgear and controlgear, providing foundational definitions and requirements referenced in Part 2.
- IEC 61000-4-2: Electromagnetic compatibility testing, especially electrostatic discharge immunity relevant to circuit-breaker testing.
- IEC 61140: Protection against electric shock, common aspects for installation and equipment safety.
- CISPR 11 & CISPR 32: Standards addressing radio-frequency disturbance emissions to reduce interference with other equipment.
- IEC 60228: Specifications for conductors in insulated cables used with circuit-breakers.
- IEC 61545: Connecting devices for aluminum and copper conductors in switchgear terminals.
These complementary standards ensure integrated compliance across electrical installation components for optimized safety and performance.
Adherence to IEC 60947-2:2016/AMD1:2019 enables stakeholders to leverage a clear, up-to-date framework for designing, specifying, and deploying low-voltage circuit-breakers that meet international benchmarks for quality, safety, and operational reliability. This contributes to safer electrical networks and supports efficient power management in diverse applications.
