Key takeaways
- Installation runs in a fixed order: civil works, structures, modules, DC cabling, inverters, AC side, earthing and protection
- Every connection is a potential fault: torque, crimping, gland sealing and labelling matter
- Commissioning proves the plant: insulation resistance, polarity, string voltages and currents, earth resistance, protection and grid tests
- Inspection and approvals (DISCOM, CEIG) come before energisation
- At handover you should receive as-built drawings, test reports, warranties, approvals and an O&M manual
Before anyone picks up a tool
- Approved layout and single-line diagram; structure and foundation design
- Safety plan, permits and inductions for every worker; the client's site rules signed off
- Material receipt checks: module and inverter models, serial numbers and certificates matched to the specification
- A storage area that keeps modules flat, dry and secure
Stage by stage: installation
- Civil worksEarth-pit chambers and covers, equipment foundations for inverters, ACDB and ITB, cable trenches, and for ground-mount plants the piles or foundations, drainage and fencing.
- Module mounting structuresErect and align the structures to the design tilt and levels; torque every bolt; on sheet roofs, fix to purlins with the right clamps and seal every penetration.
- Module installationMount modules with the specified clamps and torque; keep gaps for expansion; do not stand on modules.
- DC cabling and stringingConnect module to module and run string cables in UV-protected conduit or trays to the combiner boxes or inverters; crimp MC4 connectors with the right tool; label every string.
- InvertersMount inverters on their stands or foundations with ventilation clearance; terminate DC and AC cables; configure grid settings.
- AC sideLay armoured AC cables to the ACDB and the point of connection; terminate with proper glands and lugs.
- Earthing and protectionSeparate DC and AC earthing with tested earth pits; lightning arrestors; surge protection devices; equipotential bonding of structures.
- AncillariesModule cleaning system, walkways or lifelines, safety signage, fire extinguishers and monitoring.
Commissioning: the tests that prove the plant
| Test | What it checks | Typical acceptance |
|---|---|---|
| Visual inspection | Damage, mounting, cable routing, labels, clearances | No defects; matches drawings |
| Polarity and continuity | Every string wired correctly | Correct polarity on every string |
| String open-circuit voltage (Voc) | Correct number of modules and no faulty ones | Within a few per cent of expected for the conditions |
| String short-circuit or operating current | Strings performing alike | Strings matched within tolerance for the irradiance |
| Insulation resistance | No leakage from DC conductors to earth | Above the minimum for the system voltage |
| Earth resistance | Earthing system effective | Within the design value |
| Inverter functional tests | Start-up, grid synchronisation, anti-islanding and protection settings | Operates and trips as specified |
| Performance check | Output against irradiance | Consistent with the design yield |
Tests are recorded on formats that follow IEC 62446-1 and the DISCOM's and Electrical Inspector's requirements, so the same records serve the client, the approvals and future O&M.
Inspection, approvals and going live
- DISCOM inspection and, where required, the Electrical Inspector's (CEIG) inspection
- Installation of the bidirectional or generation meter
- Synchronisation with the grid and, at tea estates and factories with diesel back-up, with the DG sets
- Commissioning certificate and, for scheme projects, portal updates
What you should receive at handover
- As-built layout and single-line diagram
- Test reports for every string and every test above
- Equipment list with serial numbers, warranty certificates and BIS / ALMM documents
- Approvals: DISCOM, net-metering or open-access, CEIG
- O&M manual, cleaning procedure and a contact for faults
- Training for the site electrician or estate team
On many of our projects the installation & commissioning scope also includes collecting the warranty certificates and the client's I&C-cum-handover certificate, so the plant owner and the EPC both close the project with a complete file.
Need an installation & commissioning partner for a rooftop or ground-mount plant? Our veteran-led crews work Pan-India.
Get a free solar quoteFrequently asked questions
What does installation and commissioning (I&C) of a solar plant include?
Civil works for equipment, mounting structures, module installation, DC and AC cabling, inverters, earthing and protection, then testing, inspection, grid synchronisation and handover.
How long does it take to install a 1 MW solar plant?
With materials on site and approvals moving, installation of a 1 MW rooftop or ground-mount plant typically takes several weeks; approvals can add more. Weather and site access matter.
What tests are done when a solar plant is commissioned?
Visual inspection, polarity and continuity, string Voc and current, insulation resistance, earth resistance, inverter functional and protection tests, and a performance check.
What documents should I get after solar installation?
As-built drawings, test reports, equipment and warranty documents, approvals, an O&M manual and training for your team.
Sources
- PIB: MNRE notifies the revised Quality Control Order for solar photovoltaic products
- Mercom India: Net metering approved for rooftop solar up to 500 kW
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
