MNRE Issues Draft Guidelines For Series Testing Of Solar Inverters Under 2025 Solar Goods Order

The Ministry of New and Renewable Energy (MNRE) has released draft guidelines for the series approval of solar photovoltaic (SPV) inverters for testing in laboratories. This step supports the implementation of the “Solar Systems, Devices, and Components Goods Order, 2025.” The guidelines aim to help test labs and manufacturers organize the approval process for different models of solar inverters under a common series, especially when changes in design or materials occur.

These guidelines apply to SPV-based off-grid, grid-tied, and hybrid inverters. According to the document, a product family is defined based on the maximum configuration of components and sub-assemblies, where all models share the same essential hardware and firmware. For safety and performance testing, the highest-rated model in a series is tested under standards IS 16221 (Part 2):2015 and IS 16169:2019, and one report is issued covering all lower-rated models in the series. However, for standards like IS/IEC 61683:1999 and IS 17980:2022 (IEC 62891:2020), each model must be tested individually since their efficiency may vary.

All inverters under a family must have the same input/output voltage, frequency, number of output phases, PCB layout, insulation class, control algorithm, and cabinet design. Any changes in internal components, construction, or firmware that affect safety require retesting. Each product model must include a label containing essential details such as the manufacturer’s name, model number, input/output ratings, and protection rating. If fuse ratings are specified, markings must be placed near the fuse holder.

Manufacturers must submit various technical documents with their samples, including datasheets, single-line diagrams, PCB layouts, BOM lists, firmware versions, and manuals. Test labs must verify that all required documentation is submitted before beginning tests. If a sample has already been submitted or is in the process of submission, manufacturers must provide an undertaking to comply with the new guidelines for BIS registration.

In case of test failure, manufacturers are allowed to resubmit a new sample, and only the failed test sequence will be repeated after reviewing component and construction changes. However, only one failure is permitted per test sequence. Any further failure results in disqualification.

For safety tests, two samples of the maximum-rated model must be submitted, and tests must be conducted as per IS 16221 (Part 1 and 2). Labs and manufacturers are encouraged to collaborate during critical tests to ensure proper setup and execution.

Additionally, the guidelines emphasize that the confidentiality of submitted documents must be maintained by the test laboratories. The document also notes that products manufactured at two different locations must be tested separately. All brand names and model numbers must be listed in the test reports, even if only the highest-rated model is physically tested.

These guidelines are now open for stakeholder comments, which can be submitted within 15 days to the email addresses mentioned in the memorandum. Once finalized, these guidelines will be mandatory for all relevant products seeking BIS registration under the new solar goods order.