Overview
IEC 62938:2020 is an international standard published by the International Electrotechnical Commission (IEC) that specifies a testing method for evaluating the mechanical performance of framed photovoltaic (PV) modules under non-uniform snow loads. This standard focuses on framed PV modules with frames that extend beyond the front glass on the lower edge, creating a barrier that affects snow sliding. The test determines the mechanical load limits of PV modules subjected to inclined, uneven snow accumulation-commonly encountered in real-world installations on sloped roofs.
By standardizing the method to assess snow load endurance, IEC 62938:2020 helps manufacturers, installers, and certification bodies ensure PV module reliability and safety in snowy environments, mitigating risks related to structural failure such as glass breakage and frame bending.
Key Topics
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Scope and Applicability
IEC 62938:2020 applies exclusively to framed PV modules where the lower edge frame protrudes beyond the glass surface to act as a snow barrier. It excludes frame types like backrails or others that do not impact snow sliding. The standard covers natural snow load effects but does not cover artificial accumulations or steep installations (>60°).
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Non-Uniform Snow Load Testing
The core of the standard details the procedure to simulate inclined, uneven snow loads on mounted PV modules. It specifies load distributions, test apparatus setup, and the incremental application of loads that reproduce field failure conditions.
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Mechanical Load Limits
The test determines the threshold mechanical load that causes damage such as glass cracking or frame deformation. This non-uniform load limit is critical for confirming structural integrity.
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Test Procedures and Measurements
The document outlines comprehensive testing steps including:
- Visual inspections before and after loading
- Electric performance tests such as maximum power characterization, insulation, wet leakage current, and electroluminescence imaging
- Humidity-freeze cycles to assess environmental resistance
- Statistical evaluation of test data to establish load limits with safety factors
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Terminology and Definitions
The standard references key technical terms such as characteristic snow load (S), snow load shape coefficient (μ_i), specific snow weight (γ), and others defined in IEC TS 61836 to ensure uniform understanding in the industry.
Applications
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PV Module Design Qualification
Manufacturers use IEC 62938:2020 testing to validate the structural robustness of module frames against real-world snow load scenarios, enabling accurate design verification per regional snow load requirements.
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Certification and Compliance
Certification bodies incorporate this testing standard as part of qualification protocols-ensuring that PV modules can withstand non-uniform snow loads before market release.
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Installation Guidelines and Risk Mitigation
Installation engineers reference the standard to choose appropriate PV modules based on expected snow load conditions, minimizing mechanical failures on roofs in snowy climates.
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Product Development and Innovation
By exposing modules to realistic snow load distributions, product developers can innovate frame designs that better resist snow-induced stresses, driving higher reliability and longevity.
Related Standards
- IEC 61215-1:2016 & IEC 61215-2:2016 – Design qualification and type approval tests for terrestrial PV modules, which cover broader environmental and mechanical tests.
- IEC TS 60904-13:2018 – Electroluminescence testing of photovoltaic modules, referred to for detailed imaging during mechanical testing.
- IEC TS 61836 – Terms, definitions, and symbols related to solar photovoltaic energy systems, supporting consistent terminology.
- IEC TS 62915 – Retesting methods for PV module type approval, complementing the reliability assessment practices.
By adhering to IEC 62938:2020, stakeholders in the solar energy industry ensure that photovoltaic modules maintain structural integrity under adverse snow load conditions, safeguarding investment and operational efficiency. This standard plays a crucial role in advancing safe and durable PV installations in cold climates prone to non-uniform snow accumulation.