Overview
IEC 60947-4-3:2020 is the third edition international standard for low-voltage switchgear and controlgear covering semiconductor controllers and semiconductor contactors for non-motor loads. It applies to equipment intended for AC circuits with a rated voltage up to 1 000 V AC and specifies requirements for changing AC circuits between ON and OFF states, operation with or without bypass switching, and controllers that reduce RMS AC voltage. This 2020 edition replaces the 2014 edition and includes technical revisions addressing scope exclusions, safety aspects, power consumption measurement, and alignment with IEC 60947-1:2020 and IEC 60947-4-2.
Key Topics and Technical Requirements
- Scope and classification: Types of semiconductor contactors/controllers, number of poles, kind of current and interrupting medium.
- Constructional requirements: Materials, current-carrying parts, clearances/creepage distances, enclosures, terminals, protective earthing and dedicated wiring accessories.
- Performance requirements: Temperature-rise, dielectric properties, normal load/overload performance, coordination with short-circuit protective devices (SCPD).
- Safety aspects: General safety, limited-energy circuits, electronic circuits, stored charge and fault/abnormal condition handling.
- Testing regimes: Type tests, routine and sampling tests covering dielectric tests, temperature-rise, short-circuit behavior, EMC immunity and emission tests.
- Product information & marking: Marking, terminal identification, installation and maintenance instructions, and environmental information.
- EMC and power characteristics: Electromagnetic compatibility requirements and power consumption measurement for semiconductor devices.
- Annexes: Informative and normative annexes provide guidance on typical service conditions (e.g., heating elements, lamps, transformers, capacitor banks), modified short-circuit test circuits and protective separation.
Practical Applications
- Switching and controlling non-motor AC loads in industrial and commercial installations (resistive heating, lighting controls, transformers, capacitor banks).
- Use where reduced RMS voltage or soft switching is required to limit inrush or improve load life.
- Integration into control panels, building electrical systems, HVAC and industrial process equipment where solid-state switching is preferred.
Who Should Use This Standard
- Manufacturers of semiconductor contactors and controllers - for design, type testing and marking compliance.
- Test laboratories and certification bodies - to perform type and routine tests (temperature-rise, dielectric, EMC, short-circuit).
- Electrical system designers, OEMs and panel builders - for selection, integration and coordination with protective devices.
- Specifiers, procurement and compliance engineers - to ensure safety, EMC and performance in procurement and regulatory compliance.
Related Standards
- IEC 60947-1:2020 (general rules for low-voltage switchgear and controlgear) - alignment and common requirements.
- IEC 60947-4-2 - relevant when aligning semiconductor contactor requirements for other load types.
Keywords: IEC 60947-4-3:2020, semiconductor controllers, semiconductor contactors, low-voltage switchgear, non-motor loads, solid-state switching, EMC, short-circuit testing, rated voltage 1000 V AC.