MNRE Issues New Testing Rules For Solar Modules

The Ministry of New and Renewable Energy (MNRE) has issued updated guidelines for the classification and testing of solar modules, aimed at strengthening quality assurance in the sector.

Under the new rules, designated laboratories will carry out testing based on revised standards. All solar modules must now be registered with the Bureau of Indian Standards (BIS) under the Solar Systems, Devices and Components Goods Order, 2025.

The guidelines mandate the disclosure of any design or material changes during performance testing. Modules that differ from previously approved configurations must undergo partial or full retesting.

A “product family” is defined as a group of modules sharing the same basic construction, components and design, with variations clearly documented.

Sample selection

According to the draft guidelines, 12 solar modules must be randomly selected from production batches for testing. These must be built using specified materials and components, based on approved process sheets and technical drawings. Each unit must pass standard quality control procedures.

Modules must be delivered fully assembled and include handling, mounting and connection instructions, including maximum system voltage. Bypass diodes are mandatory where applicable. For modules with sealed junction boxes, an extra unit with accessible diodes must be provided for testing.

Cemented joint testing

To qualify cemented joints, two unframed PV modules must be tested under Sequence B – one with the front side and one with the rear side exposed to light. The front-facing sample will be evaluated.

If the MST 35 peel test is used, an additional module is needed to verify adhesion strength. For glass/glass modules, 20 extra samples are required for lap shear strength testing under MST 36.

All test specimens must be technically identical. Structurally complete but non-functional modules may be used for certain tests, including MST 24 and MST 32. Random selection is required for most tests, except MST 35 and MST 36.

Retesting criteria

Any design, material or manufacturing process change triggers mandatory retesting under the IS/IEC 62915:2023 standard.

Manufacturers must report any deviations from previously approved designs and provide supporting data. Retesting may be waived or reduced if evidence shows that performance is not affected.

Changes in material dimensions or thickness will be judged against the originally tested sample. If a new parameter exceeds the declared tolerance – for example, a 10% reduction in glass thickness – the module must be retested under worst-case conditions.