Solar inverters sold in India require Bureau of Indian Standards (BIS) certification under the applicable IS standards before they can legally enter the market. For government-scheme projects, they additionally require listing in ALMM Part III — the MNRE’s approved inverter register. In 2023, the MNRE began enforcing ALMM Part III compliance for SECI tenders and state DISCOM tenders, catching several EPC companies mid-project with non-compliant inverters. This guide covers the full BIS inverter certification process, the applicable standards, timeline, cost estimates, and what the ALMM Part III requirement means for your BOQ preparation.
Direct answer. BIS certification for solar inverters in India is required under the Quality Control Order for Solar Photovoltaic Systems, Devices and Components (2022). The applicable standard for grid-connected inverters is IS 16221 Part III (or IS/IEC 62116 for anti-islanding and IS/IEC 61727 for grid interface). The certification process involves factory registration with BIS, product testing at a BIS-recognised laboratory, and obtaining a BIS Registration Number (BRN). For ALMM Part III, a separate MNRE factory audit is required. Total timeline from application to BRN: 6–14 months. Estimated cost: ₹15–35 lakh per inverter model for a new applicant.
This guide is written for Rohan — the India C&I EPC founder sourcing inverters for government-scheme projects — and covers everything needed to navigate the BIS and ALMM inverter compliance process in 2026.
The Legal Framework — Which Standards Apply to Which Inverters
Solar inverters in India are governed by a stack of standards, each covering a different functional aspect:
Definition. BIS certification for solar inverters means the product has been tested to the applicable IS standard at a BIS-recognised laboratory and registered with BIS. The BIS Registration Number (BRN) confirms this. ALMM Part III means the inverter manufacturer has additionally passed the MNRE's factory audit and the inverter model is listed in the MNRE's Approved List of Models and Manufacturers for inverters — a separate register from the BIS BRN.
| Standard | Coverage | Mandatory For |
|---|---|---|
| IS 16221 Part III | Grid-connected solar inverters (power electronics, electrical safety) | BIS registration, legal sale in India |
| IS/IEC 62116:2014 | Anti-islanding protection for grid-connected PV inverters | BIS testing prerequisite |
| IS/IEC 61727:2004 | Grid interface characteristics (voltage, frequency, power quality) | BIS testing prerequisite |
| IS/IEC 62109-1 | Safety of power converters for use in PV power systems (Part 1: General) | BIS safety testing |
| IS/IEC 62109-2 | Safety of power converters — inverter specific | BIS safety testing |
| CEA Technical Standards 2019 | Grid code compliance (reactive power, ride-through, protection) | Connectivity approval |
For practical BOQ purposes: an inverter needs IS 16221 Part III BIS registration for legal sale, and ALMM Part III listing for government-scheme projects.
Step-by-Step BIS Inverter Certification Process
The BIS certification process for solar inverters follows the BIS Scheme II (testing and certification for electronic products). Here is the process a manufacturer — or an EPC helping a manufacturer navigate the system — must follow:
Step 1 — BIS Factory Registration
The manufacturer must be registered with BIS as a solar inverter manufacturer. This requires:
- Company registration documents
- Factory premises verification (BIS factory inspection)
- Quality management system documentation (ISO 9001 is preferred but not mandatory)
- List of products intended for BIS registration
Factory inspection is conducted by a BIS official or empanelled inspection agency. Timeline: 30–60 days. Cost: approximately ₹50,000–1,50,000 in inspection fees.
Step 2 — Product Sample Testing
The manufacturer submits product samples to a BIS-recognised testing laboratory. For solar inverters, the BIS-recognised labs include:
- CPRI (Central Power Research Institute), Bangalore
- ERDA (Electrical Research and Development Association), Vadodara
- CPRI Regional Laboratories (Bhopal, Hyderabad)
- Certain NABL-accredited private labs with BIS empanelment
The test sequence for IS 16221 Part III covers:
8–16 weeks
Testing timeline at CPRI/ERDA
BIS Scheme II, 2024 lab queue
₹8–18 lakh
Testing fee per inverter model
CPRI test schedule, 2025
3–6 months
BIS BRN issuance after test pass
BIS Scheme II processing time
Step 3 — BIS Application and BRN Issuance
After the test report is passed, the manufacturer submits:
- Passed test report from BIS-recognised laboratory
- Factory inspection report
- Company and product documentation
- BIS registration fee (₹2–10 lakh depending on product category and capacity)
BIS reviews and issues the BRN within 3–6 months of application. The BRN is product-specific (one inverter model = one BRN).
Step 4 — Surveillance and Renewal
BIS conducts annual factory surveillance inspections to verify ongoing compliance. The BRN must be renewed annually. An inverter manufacturer that fails the surveillance inspection loses their BRN, making their products non-compliant for Indian procurement.
The ALMM Part III Process — Additional to BIS
ALMM Part III is the MNRE’s inverter approval list, separate from and additional to the BIS BRN. The ALMM Part III process:
BIS BRN as Prerequisite
The manufacturer must have a valid BIS BRN for the inverter model before applying for ALMM Part III. No BRN = no ALMM eligibility.
MNRE Factory Audit
An MNRE-empanelled third-party inspection agency conducts a factory audit covering manufacturing capacity, quality control processes, production infrastructure, and component sourcing. The audit report is submitted to MNRE with the ALMM application.
ALMM Application to MNRE
Submit the ALMM Part III application to MNRE with BIS BRN, factory audit report, product technical specifications, and manufacturing capacity declaration. MNRE reviews and lists the model on ALMM Part III if the application is complete and the factory audit passes.
Annual Re-Audit and Renewal
ALMM Part III listing requires annual re-audit by an MNRE-empanelled agency. A failed re-audit results in suspension from the ALMM list, making the inverter model non-compliant for government-scheme procurement immediately.
Timeline and Cost Summary
| Stage | Timeline | Estimated Cost |
|---|---|---|
| BIS Factory Registration | 30–60 days | ₹50,000–1,50,000 |
| Product Sample Testing (CPRI/ERDA) | 8–16 weeks | ₹8–18 lakh per model |
| BIS Application Processing | 3–6 months | ₹2–10 lakh |
| MNRE Factory Audit (ALMM Part III) | 4–8 weeks | ₹2–5 lakh |
| ALMM Part III Application Processing | 2–4 months | No direct fee |
| Total (BIS + ALMM) from scratch | 6–14 months | ₹15–35 lakh per model |
Watch out. These timelines assume a smooth process with no test failures or documentation rejections. A single failed test sequence at CPRI adds 8–12 weeks for retesting and sample preparation. Budget 20–30% additional time buffer for first-time applicants unfamiliar with the BIS documentation requirements.
What BIS and ALMM Compliance Means for Your BOQ
When writing a BOQ for a government-scheme solar project, the inverter specification must address compliance across three dimensions:
1. Technical specification: capacity (kW/MW), input voltage range, MPPT range, efficiency (European weighted or CEC), power factor capability, grid code compliance parameters.
2. BIS compliance: specify “BIS-registered under IS 16221 Part III with valid BRN at time of procurement and delivery.”
3. ALMM compliance: for projects above 1 MW under government schemes, specify “ALMM Part III listed at time of procurement and delivery.”
The BOQ should also include a contingency clause: “In the event that the specified inverter model is delisted from ALMM Part III between order placement and delivery, the supplier must obtain written approval from the EPC and client for a pre-approved substitute ALMM Part III listed inverter model.”
Comparing BIS-Certified Inverter Options — Indian vs International Manufacturers
INDIAN MANUFACTURERS
- Typically faster BIS renewal (in-house BIS-recognised lab)
- Domestic after-sales service network
- Pricing in ₹ with no currency risk
- ALMM Part III listing process is generally faster
- Examples: Sungrow India, Growatt India, TMEIC, Luminous, Solaredge India
INTERNATIONAL MANUFACTURERS
- BIS certification requires re-testing at Indian lab (even with IEC 62116 cert)
- Currency risk if pricing in USD/EUR
- Spare parts logistics may be slower
- ALMM Part III factory audit requires Indian-based representative
- Examples: SMA, ABB/Fimer, Fronius (some models BIS-registered)
Common Reasons BIS Applications Fail — And How to Avoid Them
Understanding why BIS applications fail saves months of delay. The most frequent failure modes for solar inverter BIS certification in India are:
1. Incorrect product sample submission. BIS requires samples that are genuinely representative of the production version. Manufacturers sometimes submit pre-production or prototype units that pass the lab but differ from the actual production design. If BIS surveillance detects inconsistencies between the certified design and the manufactured product, the BRN is suspended. Submit samples drawn directly from the production line with a serialised chain of custody log.
2. Test report scope gaps. IS 16221 Part III requires a complete test report covering all sub-clauses. Manufacturers sometimes present partial test reports (e.g., covering only efficiency and protection, omitting EMI/EMC sub-clauses) and expect the BIS reviewing officer to accept the partial report pending a supplementary. BIS does not accept partial reports. Ensure the testing laboratory provides a complete test report against every applicable sub-clause of IS 16221 Part III, IS/IEC 62116, and IS/IEC 62109-1 and 62109-2 before submission.
3. Documentation mismatch between factory registration and product BRN. The company name, factory address, and product description on the factory registration must match exactly with the BRN application. A manufacturing entity that produces inverters at multiple factory locations must register each location separately. A single mismatch — e.g., “Private Limited” vs “Pvt. Ltd.” in the company name — can trigger a return-for-correction that costs 30–60 days.
4. ALMM factory audit gaps. MNRE’s empanelled audit agencies look for four things: manufacturing capacity commensurate with declared production, quality control documentation (SOPs, inspection records, non-conformance logs), component sourcing traceability (which cell/PCB suppliers are used), and testing equipment calibration records. Manufacturers that cannot produce 12 months of quality control records or lack calibrated testing equipment at the factory fail the ALMM audit and must reapply after corrective action.
Field tip. If you are helping an inverter manufacturer navigate BIS, request the full IS 16221 Part III standard from BIS before the first lab interaction. Cross-check every sub-clause against the proposed test plan with the laboratory. This single step eliminates the most common cause of failed or incomplete test reports.
Inverter Technology Trends and BIS Certification Implications
The BIS certification landscape for inverters is evolving alongside inverter technology. Three trends in 2025–2026 have direct certification implications:
String inverters vs central inverters: The Indian market is shifting toward string inverters for utility-scale projects (1–5 MW strings replacing 1,000+ kW central inverters). BIS BRN is issued per model, so a manufacturer offering a 125 kW string inverter needs a separate BRN from their 50 kW model. EPCs specifying string inverters for large projects should verify BRN coverage for every capacity tier in the specified product line.
Hybrid inverters with BESS functionality: Hybrid inverters that include integrated battery charge/discharge capability sit in a grey zone for BIS certification in 2026. The IS 16221 Part III standard was written for grid-connected solar-only inverters. MNRE has issued guidance that hybrid inverters with BESS functionality must be certified under IS 16221 Part III (for the PV conversion function) AND must comply with the emerging BESS inverter quality control order (currently in consultation phase as of 2026). Specifying hybrid inverters in government-scheme BOQs without confirming this dual compliance is a procurement risk.
Microinverters: Microinverters (≤2 kW per unit) used in rooftop systems are subject to the same IS 16221 Part III requirement. In practice, few foreign microinverter manufacturers have obtained BIS BRNs for the Indian market. EPCs specifying microinverters for government-scheme rooftop projects — PM Surya Ghar or state net metering schemes — must verify BIS and ALMM compliance, as non-compliant microinverters cannot be specified in government-funded systems.
| Inverter Type | BIS Standard | ALMM Required (>1 MW govt scheme) | 2026 Status |
|---|---|---|---|
| String inverter (>10 kW) | IS 16221 Part III | Yes | Mature, most major brands BIS-registered |
| Central inverter (≥500 kW) | IS 16221 Part III | Yes | Mature, limited to large manufacturers |
| Microinverter (≤2 kW) | IS 16221 Part III | Yes (if govt-funded) | Few brands BIS-registered in India |
| Hybrid inverter (PV + BESS) | IS 16221 III + pending BESS QCO | Subject to MNRE clarification | Grey zone — verify before specifying |
| Off-grid inverter | IS 16221 Part I/II (off-grid) | No (unless specific scheme) | Separate certification track |
Impact of BIS Compliance on Project Financing and DISCOM Approvals
Lenders providing project finance for solar projects in India — IREDA, PFC, SBI, REC, and commercial banks — increasingly include inverter BIS compliance as a covenant in the loan agreement. A project that reaches COD with non-BIS-compliant inverters may face:
- Technical due diligence reports flagging non-compliance (reducing lender confidence and potentially triggering loan covenant violations)
- DISCOM refusal to issue the grid connectivity approval or the Net Metering Connectivity Letter if the inverter does not carry a BIS BRN
- SECI or implementing agency refusal to issue the Provisional Acceptance Certificate (PAC) or Final Acceptance Certificate (FAC) for ALMM non-compliant inverters on government-scheme projects
The bankable energy yield report is only one element of a bankable project package. The equipment compliance chain — module BIS (IS 16221 Part I), inverter BIS (IS 16221 Part III), ALMM listing for both — is equally scrutinised by independent engineers and lenders.
Note. DISCOM requirements for inverter compliance documentation vary by state. Some DISCOMs require only the BIS BRN number in the connectivity application; others require a physical copy of the BRN certificate and the test report. Check the specific DISCOM's connectivity application format before finalising your commissioning documentation pack.
Reading the BIS and ALMM Databases — A Practical Guide
Both the BIS registration database and the MNRE ALMM portal are publicly accessible but require knowing how to navigate them effectively.
BIS registration search: The BIS portal maintains a searchable product registration database. To verify an inverter’s BIS BRN, search by “Product Name” (solar inverter) and “IS Number” (IS 16221). The search returns the registered manufacturer name, BRN number, date of registration, and date of expiry. Always verify expiry — an expired BRN means the product is no longer compliant.
MNRE ALMM portal: The MNRE ALMM list is updated monthly. ALMM Part III (inverters) is downloadable as an Excel or PDF showing manufacturer name, inverter model, capacity, BIS BRN cross-reference, and date of addition to the list. The date of addition matters — if a model was added after your bid submission date, it may not qualify for your specific project if the tender specified ALMM compliance “as of [date].”
Building a compliance register: For any project with more than one inverter model or multiple procurement lots, maintain a project-specific compliance register tracking: manufacturer name, model number, BIS BRN number, BRN expiry date, ALMM Part III listing date, ALMM re-audit due date, and PO reference number. This register becomes part of the commissioning documentation and satisfies both DISCOM and lender requirements in a single document.
The 4-Gate Inverter Compliance Protocol
The 4-Gate Inverter Compliance Protocol is Heaven Designs’ framework for ensuring that inverter procurement for government-scheme projects clears every regulatory gate without delay.
Gate 1 — Pre-Tender Verification: Before bid submission, verify the proposed inverter’s BIS BRN on the BIS portal and ALMM Part III status on the MNRE ALMM list. Download both documents and attach them to the bid compliance pack.
Gate 2 — Procurement Order: At the time of purchase order placement, re-verify BRN validity (expiry date) and ALMM listing date. Confirm the specific model number on the PO matches the BRN and ALMM listing exactly.
Gate 3 — Delivery Inspection: When inverters arrive at site, verify the BRN label on each unit matches the PO specification. Request the manufacturer’s Certificate of Conformance (CoC) confirming BIS and ALMM status at time of manufacture.
Gate 4 — Commissioning Documentation: Include BRN numbers, CoC, and ALMM certificate in the commissioning documentation pack submitted to the DISCOM or project implementing agency for COD certificate.
Need a BIS and ALMM compliant BOQ for your inverter procurement?
Heaven Designs prepares BOQs with BIS BRN verification, ALMM Part III cross-reference, and 4-Gate compliance documentation built in.
Get the sample pack →How Heaven Designs Helps
BIS and ALMM compliance for inverter procurement is a moving target — registration databases update monthly, BRNs expire, and ALMM listings change. Heaven Designs maintains a live compliance tracking database covering BIS-registered and ALMM Part III listed inverter models, integrated into every project BOQ and design package.
- Solar Rooftop Detailed Engineering Design — BOQ with BIS BRN and ALMM Part III verification for all inverters specified.
- Solar Ground Mount Design — utility-scale BOQ with inverter compliance chain documented.
- Engineering Documentation India — commissioning documentation pack with all compliance certificates organised for DISCOM submission.
- Electrical CEIG Drawings — CEIG-format SLD and protection diagrams cross-referencing BIS-certified inverters.
- Download a sample deliverable — see an inverter specification section with BIS and ALMM columns completed.
Contact us to get your inverter BOQ reviewed for BIS and ALMM compliance before bid submission.
FAQ
What IS standard applies to solar inverters in India?
The primary standard is IS 16221 Part III for grid-connected solar PV inverters. Supporting standards include IS/IEC 62116 (anti-islanding protection), IS/IEC 61727 (grid interface characteristics), and IS/IEC 62109-1 and 62109-2 (safety of power converters). All must be satisfied for BIS registration. The BIS solar energy standards portal lists the current applicable standards for each inverter type.
How much does BIS inverter certification cost in India?
For a new applicant obtaining BIS certification from scratch, the total cost is typically ₹15–35 lakh per inverter model, broken down as: ₹8–18 lakh for testing at CPRI or ERDA, ₹2–10 lakh for BIS registration fee, ₹50,000–1,50,000 for factory inspection, and ₹2–5 lakh for the ALMM Part III factory audit. Manufacturers with multiple models often share a base factory registration cost across models, reducing the per-model cost for subsequent certifications.
Can an inverter with IEC 62116 certification skip BIS testing in India?
No. IEC certification from international laboratories (TÜV Rheinland, UL, Bureau Veritas) is not recognised as a substitute for BIS testing. The product must be tested at a BIS-recognised laboratory in India. However, the manufacturer may be able to present the IEC test report to the BIS laboratory as supporting evidence, potentially reducing the testing scope. This must be agreed with the BIS-recognised laboratory before testing begins.
What happens if an inverter is delisted from ALMM Part III mid-project?
If an inverter is delisted from ALMM Part III after procurement but before installation, the EPC must obtain a written waiver from the project implementing agency or replace the inverters with an ALMM-listed alternative. The legal risk sits with the EPC under the EPC contract’s compliance warranty clause. To mitigate this risk, always verify ALMM status at the time of purchase order and again at the time of delivery, and document both verification dates in the compliance register.
Do off-grid or BESS inverters require BIS certification?
Off-grid solar inverters (for systems not connected to the grid) have separate BIS requirements under IS 16221 Part III or related standards. BESS inverters (battery energy storage system inverters) are covered under emerging BIS standards — as of 2026, the mandatory BIS requirement for BESS inverters is being phased in under the MNRE’s BESS quality control framework. According to MNRE’s BESS policy framework, the BIS certification requirement for BESS inverters is expected to be mandatory by 2027. Check current MNRE notifications before procuring BESS inverters for government projects.
What is the ALMM Part III and how is it different from ALMM Part I?
ALMM Part I covers solar PV modules (crystalline silicon). ALMM Part II covers solar PV cells. ALMM Part III covers solar PV inverters. All three parts are maintained by MNRE under the same Compulsory Registration Order framework. The registration process for each part is similar — BIS certification as prerequisite, MNRE factory audit, and annual re-audit — but the technical standards differ by product type. For government-scheme projects above 1 MW, all three parts may be applicable: ALMM Part I for modules, Part II for DCR cell compliance, and Part III for inverters. See MNRE’s ALMM portal for the current ALMM Part III list.
