By sion932 
The International Electrotechnical Commission (IEC) released the third edition of IEC 62271-200 in 2021, marking a significant technical revision to the standard governing AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to 52 kV. This standard serves as a cornerstone for the design, manufacturing, testing, and certification of medium-voltage switchgear assemblies, ensuring safety, reliability, and interoperability across global power systems. This article provides a detailed analysis of the scope, core technical requirements, key updates from the previous edition, and industry implications of IEC 62271-200:2021.
1. Scope and Core Objectives
IEC 62271-200:2021 applies to prefabricated AC metal-enclosed switchgear and controlgear assemblies designed for service frequencies up to 60 Hz, suitable for both indoor and outdoor installations. The standard covers assemblies with air-insulated, fluid-filled, or hybrid insulation compartments, which are widely used in power transmission and distribution networks, industrial power distribution systems, and commercial building electrical infrastructure.
The core objectives of the standard are threefold: first, to ensure the safety and reliability of switchgear under normal operating conditions as well as abnormal scenarios such as short circuits and overloads; second, to standardize key technical indicators including mechanical strength, insulation performance, and temperature rise control; third, to establish unified test methods and certification procedures to facilitate global market access, such as CE certification in the European Union.
2. Core Technical Requirements
2.1 Electrical Performance Parameters
The standard specifies clear requirements for electrical performance to ensure the switchgear can withstand the stresses of medium-voltage power systems. Rated voltages covered include 12 kV, 24 kV, 36 kV, 40.5 kV, and 52 kV, with rated current ratings typically ranging from 1250 A to 2500 A. For short-circuit withstand capability, the standard mandates type tests to verify short-time withstand current (e.g., 31.5 kA/4 s, 40 kA/1 s) and peak withstand current (e.g., 80 kA) performance.
Temperature rise control is another critical requirement: copper busbars must not exceed a temperature rise of 60 K, while contact points are limited to 65 K under rated current conditions. Additionally, the standard specifies that main circuit resistance measurement is only required before continuous current tests as a reference for routine testing, and is no longer needed afterward, as post-test measurements do not provide additional meaningful information following the temperature rise test.
2.2 Insulation Coordination
Insulation performance is paramount for medium-voltage switchgear, and IEC 62271-200:2021 defines strict requirements for insulation coordination. For power frequency withstand voltage, 12 kV systems must withstand 42 kV for 1 minute, while 24 kV systems require 65 kV endurance. Lightning impulse withstand voltage requirements are 75 kV for 12 kV systems and 125 kV for 24 kV systems, simulating the insulation strength needed to resist direct lightning strikes or switching overvoltages.
Local discharge control is also emphasized: under 1.1 times the rated voltage, the local discharge quantity must be ≤ 10 pC to ensure the long-term reliability of insulation materials. For switchgear with protrusions, the standard provides a more precise description of internal arc tests in Annex A to address potential insulation weak points.
2.3 Mechanical Performance and Environmental Adaptability
Mechanical performance requirements include strict operation life criteria: circuit breakers must complete 5000 mechanical operations (e.g., closing and opening) without failure, while disconnectors require a minimum of 2000 operations. Seismic design compliance is verified through IEC 60068-3-3 standard tests, ensuring no structural deformation and busbar contact resistance fluctuation of less than 3% under 0.5 g acceleration. Protection levels typically range from IP54 to IP66 (per IEC 60529), achieved through double EPDM sealing rings and stainless steel materials to resist salt spray and water jet intrusion.
Environmental adaptability tests cover temperature-humidity cycling (40°C/93% RH for 56 days, with insulation resistance reduction ≤ 50%), 500-hour salt spray testing (corrosion rate < 0.1 μm/year per IEC 60068-2-52), and high-altitude operation (derating 5%-15% per 1000 meters above sea level up to 5000 meters, with air pressure compensation technology to maintain insulation performance).
2.4 Safety Requirements: Internal Arc Protection and Earthing
Internal arc protection is a key safety focus of the standard. Switchgear must pass an 85 kA/0.5 s arcing test, with the maximum internal cabinet pressure limited to 50 kPa (per IEC 61641) to restrict arc propagation and protect personnel safety. The 2021 edition introduces a 1-second rule for criterion 4 during internal arc tests, distinguishing between hot gases and glowing particles as ignition sources to improve test accuracy.
Earthing circuit requirements are more precisely defined, including ratings and test requirements to ensure rapid fault current discharge (e.g., 40 kA/1 s withstand capability). Mechanical interlocking systems are mandated to prevent incorrect operations (e.g., preventing cabinet door opening when the circuit breaker is closed), complying with the “five-prevention” safety principles.
3. Key Technical Updates from the 2011 Edition
IEC 62271-200:2021 cancels and replaces the 2011 second edition, introducing numerous significant technical changes to align with industry developments and improve standard applicability:
- Clause numbering is aligned with IEC 62271-1:2017, including the adoption of subclause names from Clause 3.
- Specific definitions for “in service”, “normal operating condition”, and “normal use” are added to Clause 3 to clarify operational boundaries.
- Internal arc testing for pole-mounted switchgear is removed, as it is now covered by the specific standard IEC 62271-214:2019.
- The number of mechanical tests on interlocks for type testing is reduced, with more precise descriptions of applied forces (refer to 7.102).
- References to updated standards including IEC 62271-100:2021, IEC 62271-103:2021, IEC 62271-105:2021, and IEC 62271-106:2021 are incorporated, along with IEC 62271-107:2019 and IEC/IEEE 62271-37-013:2015 in 7.101.2.
- A more precise description of Loss of Service Continuity (LSC) categories is provided, including an explanatory flowchart in Annex D to facilitate implementation.
- Examples not covered by internal arc tests are transferred from Clause 6 to 9.103 for better organization.
- The term “assembly” is formally defined in Clause 3 and used synonymously with “metal-enclosed switchgear and controlgear” throughout the document, while “metallic” is replaced with “metal” where applicable.
4. Testing and Certification Procedures
IEC 62271-200:200 establishes a two-tier testing framework: type tests and routine tests, to ensure consistent product quality across manufacturing batches.
4.1 Type Tests
Type tests are comprehensive evaluations conducted on representative samples to validate design compliance. They include electrical tests (insulation testing, short-circuit withstand testing, temperature rise testing), mechanical tests (operating mechanism life testing, interlock function verification, seismic performance testing), and environmental tests (salt spray, high-low temperature cycling, condensation testing with insulation resistance ≥ 1000 MΩ at 95% RH). Internal arc classification (IAC) testing is a key component, with pass criteria including: doors/covers remaining closed, no dangerous fragments, no holes on accessible sides up to 2 m, non-ignition of indicators (per the 1-second rule), and effective earthing retention. IAC marking examples include “IAC A FLR 31.5 kA 1 s”, indicating accessibility type A, protection on front/lateral/rear sides, and arc current/duration ratings.
4.2 Routine Tests
Routine tests are performed on each individual unit before factory shipment to ensure manufacturing quality. They include insulation resistance testing (main circuit ≥ 1000 MΩ), loop resistance measurement (≤ 110% of the design value), and mechanical operation verification.
4.3 Certification and Market Access
Compliance with IEC 62271-200:2021 is a prerequisite for global market access. For the European Union, CE certification requires alignment with EN 62271-200, along with compliance with the Low Voltage Directive (LVD) and Electromagnetic Compatibility (EMC) Directive. Other regional certifications include China’s CCC certification (based on GB 3906) and North America’s UL certification, which recognizes equivalent IEC standard compliance with possible local laboratory retesting requirements.
5. Industry Implications and Future Outlook
The release of IEC 62271-200:2021 reflects the evolving needs of the medium-voltage power industry, driven by advancements in insulation technology, increased safety expectations, and global market integration. For manufacturers, compliance requires updating design processes to incorporate new technical requirements, such as revised internal arc testing procedures and enhanced earthing circuit design. It also necessitates aligning testing capabilities with the updated standard, potentially requiring investments in new test equipment or partnerships with accredited laboratories.
For end-users, the standard provides improved confidence in switchgear safety and reliability, particularly through enhanced internal arc protection and clearer LSC category definitions that support better service continuity planning. The unified global technical framework also simplifies product selection and comparison across different suppliers, promoting market competition and innovation.
Looking forward, as the power industry transitions toward renewable energy integration and smart grid development, future revisions of IEC 62271-200 may further address the specific needs of distributed power systems, digital monitoring capabilities, and environmentally friendly insulation materials (e.g., SF₆ alternatives). Continuous compliance with this standard will remain essential for stakeholders to navigate the evolving medium-voltage switchgear landscape.
References
[1] IEC. (2021). IEC 62271-200:2021 High-voltage switchgear and controlgear – Part 200: AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV. IEC Webstore.
[2] Sohu. (2025). An Overview of the Main Content of IEC 62271-200 Standard.
[3] Payapress. (2025). IEC 62271-200: Internal Arc, LSC and Type Tests.
[4] Intertek. (2022). White Paper: IEC 62271-200: Edition 3.0:2021 – How do I comply with the newest high-voltage switchgear and controlgear regulation?