- Ask for documented projects: purchase orders, client certificates and site visits, not just photos
- Check who will actually be on site: in-house crews and supervisors, or labour subcontracted at the last minute
- Insist on ALMM-listed modules and BIS-certified inverters named in the contract
- Ask how the contractor handles safety, approvals (DISCOM, CEIG) and testing at handover
- Compare quotations on the same specification; the cheapest bid often hides thinner cables, weaker structures or missing items
Why the partner matters more than the panel
Two plants built with identical modules can perform very differently. Structure design, cable sizing, earthing, string layout, workmanship at every connector and the quality of commissioning tests decide how much power the plant makes and how safely it runs for 25 years. That is the contractor's work.
The 12 questions
| # | Question | A good answer looks like |
|---|---|---|
| 1 | Which comparable plants have you built? | Named projects of similar size and type, with locations and dates |
| 2 | Can I see purchase orders, completion or appreciation certificates? | Documents from clients and EPC majors, and references you can call |
| 3 | Who will be on site? | Named project manager and site engineer; in-house crews for critical work |
| 4 | Which modules and inverters, exactly? | Make, model and ALMM / BIS status written into the contract |
| 5 | How is the structure designed? | Wind-load design for your location, galvanising spec, roof or pile calculations |
| 6 | How are cables sized and routed? | Voltage-drop calculation, UV-resistant DC cable, proper trays and glands |
| 7 | How do you earth and protect the plant? | Separate DC and AC earthing, lightning protection, surge devices, tested earth resistance |
| 8 | Who handles approvals? | The contractor files DISCOM, net-metering and CEIG paperwork |
| 9 | What tests will you hand over? | Insulation resistance, polarity, string Voc/Isc, earth resistance, inverter settings, as-built drawings |
| 10 | What is your safety system? | Permits, PPE, work-at-height and electrical isolation procedures, toolbox talks, ISO 45001 |
| 11 | What warranties and guarantees? | Manufacturer warranties passed on, workmanship warranty, performance commitment |
| 12 | What happens after handover? | O&M or module-cleaning options, a contact for faults, response times |
Red flags
- "Tier-1 equivalent" modules or unnamed inverters in the quotation
- No earthing or lightning-protection design, or a lump sum for "BOS" with no detail
- A price far below others on the same specification
- No site visit before quoting
- Reluctance to put approvals, testing or handover documents in the contract
How to compare quotations fairly
- Fix the specificationCapacity (kWp DC and kW AC), module and inverter class, structure type, cable sizes.
- Ask for a bill of quantitiesLine items for modules, inverters, structures, cables, earthing, LA, ACDB/DCDB, civil works, approvals.
- Compare like with likeNormalise each quote to the same scope; add the missing items to the cheaper ones.
- Check the generation estimateThe same location and assumptions should give similar yields; an outlier needs explaining.
- Read the contractPayment milestones tied to progress, delay and performance clauses, warranty start dates.
Our answers
Arrays Ingenieria is an ex-servicemen-led company certified to ISO 9001, ISO 14001 and ISO 45001. Our projects page lists our work, and our case studies carry the client certificates and press coverage behind them. We do not manufacture modules or inverters, so we specify and document the makes your project requires.
Put our answers to the test: ask us all 12 questions about your project.
Get a free solar quoteFrequently asked questions
How do I check a solar EPC company's track record?
Should the EPC contract name the module and inverter brands?
What documents should I get at handover?
Is the cheapest solar quote a bad idea?
Sources
- PIB: MNRE notifies the revised Quality Control Order for solar photovoltaic products
- PIB: MNRE amends the ALMM Order 2019 (List-II for solar cells)
This guide explains public policy in plain language for planning purposes. Rules, rates and deadlines change: confirm the current position with the notifying authority, your DISCOM and your tax adviser before you commit. Last checked 11 Oct 2026.
About the authors. Arrays Ingenieria is an ex-servicemen-led solar EPC and installation & commissioning company working Pan-India, from Assam's tea estates to industrial rooftops. Our story · Our projects
