The Ministry of New and Renewable Energy (MNRE) has released draft guidelines for the series approval of Solar Photovoltaic (SPV) Inverters, a move aimed at streamlining testing and certification processes for manufacturers. These guidelines are crucial for the implementation of the Solar Systems, Devices and Components Goods Order, 2025 which mandates compulsory registration of SPV inverters with the Bureau of Indian Standards (BIS).
The guidelines are designed to facilitate test laboratories and manufacturers in forming product series for approval, accommodating design changes, material variations, and other modifications within a product family. They are applicable to SPV-based Off-Grid, Grid-Tied, and Hybrid Inverters.
Key Provisions of the Draft Guidelines
Definition of Product Family
A product family is defined by its maximum component configuration and how models are constructed from it, sharing essential hardware and firmware (though firmware may have different limit settings based on model rating).
Testing and Certification Process
- Manufacturers must declare their product series when submitting samples to test labs.
- For registration purposes, the highest-rated model within a series will be tested to represent the entire product family for standards IS 16221 Part 2:2015 and IS 16169:2019.
- However, for standards IS/IEC 61683:1999 and IS 17980:2022 (IEC 62891:2020), each individual model must be tested separately, as efficiency can vary.
- Test labs will charge a single fee for the highest-rated inverter model for the first two standards, issuing a single test report for all lower-wattage models in that series. For the latter two standards, model-wise testing fees and individual test reports will apply.
- Any changes in construction, materials, or components within a product family necessitate fresh testing.
Series Guidelines (Design & Construction)
Products within a family must share identical hardware and essential firmware. Models must also have the same rated input/output voltage, frequency, number of phases at output, PCB design and layout, power stage topology, insulation class, control algorithm/firmware, and cabinet design and construction class. If cabinet design changes, all different designs must be tested or verified for Ingress Protection (IP).
Documentation Requirements
Manufacturers must provide comprehensive documentation with samples, including product datasheets, a complete Bill of Materials, safety certificates for critical components, schematics, PCB layouts, user manuals, and firmware details. Test labs are instructed not to accept inverters for testing without these details.
Marking
All inverters are required to have clear and indelible markings on their labels, including the manufacturer/supplier name, model and serial number, input/output electrical characteristics, and IP rating, as per IS 16221 Part 2, Clause 5.
Retesting Guidelines
The guidelines also detail procedures for retesting in case of test failures, allowing for one failure per testing sequence before a total failure is declared.
The MNRE has invited comments from stakeholders on these draft guidelines. Submissions should be sent via email to kamlesh.yadav@nise.res.in with a copy to rajkumarb.mnre@gov.in.
The deadline for submitting comments is within 15 days from the notification date of this Office Memorandum, which is June 23, 2025. These guidelines will come into force from the date of their official notification by the MNRE.
