A solar EPC handover checklist is the list of documents, records, readings and access rights an EPC hands to the O&M team when a plant is commissioned. For plants in India, it should include as-built drawings, an equipment register, warranty papers, baseline readings, monitoring logins and a named contact tree.
Key Takeaways
- As-built, not design: drawings must show what was actually installed, including string maps and cable routes.
- Warranty clocks: record the start date, serial number and claim contact for every module, inverter and meter.
- Baselines: without day-one readings, an O&M team cannot prove a fault is new or old.
- Access: monitoring, inverter and portal credentials should be transferred to the owner, not held by one engineer.
- Sign-off: a joint walkdown with a signed punch list prevents disputes months later.
Handover Pack at a Glance
| Item | What to hand over | Why O&M needs it |
|---|---|---|
| As-built drawings | SLD, layout, string maps, cable schedule | Fault tracing and safe isolation |
| Equipment records | Serial numbers, datasheets, inverter settings | Spares and warranty claims |
| Warranties | Certificates, start dates, claim contacts | Claims within the valid period |
| Baseline readings | Voc/Isc, insulation, earth resistance, thermography, PR | Comparison point for future faults |
| Monitoring access | Logins, RTU/SIM details, alarm limits | Alerts reach the right people |
| Contacts | EPC, OEM, DISCOM, site staff | Fast escalation |
Most handover disputes are not about big failures. They start with a missing string map or an unknown inverter password. The EPC has moved to the next project, and the O&M team is guessing. A tight pack avoids that, and it protects the EPC’s own reputation after the final invoice.
Tick-Box Handover Tracker
Copy this into a spreadsheet and fill it in at the walkdown. Each row needs a responsible party, a “received” tick and a date.
| Item | Responsible party | Received (tick) | Date received |
|---|---|---|---|
| ☐ SLD (AC and DC), layout, string map, cable schedule | EPC design lead | ☐ | |
| ☐ Earthing and lightning protection layout | EPC design lead | ☐ | |
| ☐ Equipment register with serial numbers | EPC site engineer | ☐ | |
| ☐ Inverter parameter files (exported) | EPC commissioning engineer | ☐ | |
| ☐ Module, inverter and workmanship warranties | EPC project manager | ☐ | |
| ☐ Net metering or DISCOM approval letters, meter seal reports | EPC project manager | ☐ | |
| ☐ Baseline readings with instrument make and calibration date | EPC commissioning engineer | ☐ | |
| ☐ Owner-level monitoring accounts and alarm thresholds | EPC monitoring lead | ☐ | |
| ☐ Contact tree | EPC project manager | ☐ | |
| ☐ Safety approvals, shutdown procedure, spares list | EPC site engineer | ☐ | |
| ☐ Signed punch list | Owner and O&M supervisor | ☐ |
1. As-Built Drawings and Design Records
As-built drawings show the plant as it was built, with every change made on site. Design drawings often differ after cable rerouting or inverter relocation, so ask for revised copies.
- Single line diagram (AC and DC) with breaker and protection ratings
- Array layout with table, string and module numbering
- String map linking each string to its inverter MPPT input
- Cable schedule: sizes, lengths and routes
- Earthing and lightning protection layout
- Structural drawings and roof load notes for rooftop plants
Provide both PDF and editable CAD files. Label each with revision number and date. A technician hunting a string fault needs the string map more than any other drawing.
2. Equipment Records and Serial Numbers
An equipment register lists every major asset with make, model, serial number, rating and location. It is the base for spares, warranty claims and later upgrades.
What the register should hold
- Module make, wattage, count and batch or pallet numbers
- Inverter model, serial number, firmware version and commissioning date
- Transformer, ACDB, DCDB, meter and SPD details
- Inverter parameter file: grid limits, power factor, zero export settings if used
- OEM datasheets and O&M manuals
Save the inverter configuration as exported files. After a replacement, the new unit can be set up in minutes rather than guessed from memory.
3. Warranties and Certificates
Hand over every warranty with its start date, term and claim route. A warranty nobody can find is effectively void. Our guide to the solar panel warranty claim process in India shows why paperwork decides outcomes.
- Module product and performance warranty certificates
- Inverter warranty, including any extension purchased
- EPC workmanship warranty and defect liability period end date
- Test reports: factory test certificates, commissioning and grid synchronization approvals
- Net metering or DISCOM approval letters, and the meter seal reports
Ask the EPC to name each DISCOM document by its reference number and date on the tracker. Typical names are the net metering approval, the grid synchronization approval and the meter seal report. Exact titles differ by state, so copy them from the letters your own DISCOM issued rather than from a template.
Also note what voids cover, such as unapproved cleaning chemicals or unauthorised inverter opening. O&M staff should know these limits before the first visit.
4. Baseline Readings
Baseline readings are day-one measurements taken at commissioning. They give O&M a reference, so a drop later can be judged against real numbers instead of opinion.
- String open-circuit voltage and short-circuit current, with irradiance and module temperature
- Insulation resistance of DC strings and cables
- Earth pit resistance values
- Thermal imaging of modules, connectors and combiner boxes
- Inverter efficiency and initial performance ratio
- First 30 days of generation, with weather notes
Record the instrument make and calibration date. Field techniques are covered in our shading loss diagnosis guide, which also shows why shading at commissioning should be logged.
Ask the EPC to state which commissioning test standard or guideline the readings follow, such as IEC 62446-1 if that is what the contract specifies. Write the name on the baseline sheet so later readings use the same method.
Worked Example: Proving a Fault Is New
The numbers below are hypothetical, to show the method. Suppose string 4 on inverter 2 was recorded at commissioning, and re-measured after an alarm.
| Reading | Baseline (commissioning) | Later visit | Reading |
|---|---|---|---|
| String 4 Voc | 900 V | 855 V | Down 45 V |
| String 4 insulation resistance | 200 MΩ | 2 MΩ | Down sharply |
| String 5 Voc (neighbour) | 900 V | 899 V | Unchanged |
The Voc drop of 45 V is 900 minus 855. The neighbouring string is unchanged, so weather and irradiance are not the cause. The insulation fall points to damaged cable or connectors rather than a design flaw.
Because the baseline sheet shows healthy values on day one, O&M can show the owner the fault is new. It can then raise a defect liability claim if the period is still running. Without the baseline, the EPC could argue the string was always weak.
5. Monitoring Access and Communication
Hand over monitoring access as owner-level accounts, not personal logins. Include portal URLs, user roles, RTU or dongle details, SIM numbers and alarm thresholds.
- Admin credentials for inverter portals, with a password change on handover
- Data logger or RTU make, IP or SIM details, and recharge validity
- Alarm thresholds and who receives each alert
- Meter and weather sensor calibration records
- Plant capacity, tilt and expected generation figures loaded in the dashboard
Check that the dashboard matches the string map. A mislabelled string makes an alert useless. For what to look at daily, see what a solar dashboard should show.
6. Maintenance Contacts and Escalation
A contact tree says who to call, in what order, for each fault type. Names and numbers should be current on the day of handover and reviewed yearly.
- EPC project manager and service lead
- Module and inverter OEM service desks
- DISCOM section office and meter contact
- Site security, facility manager and roof access authority
- O&M supervisor and 24-hour escalation number
Define response targets in the contract. Typical terms are explained in our note on solar AMC vs O&M contracts.
7. Safety, Permits and Spares
The last block covers items often forgotten. Confirm each of these before sign-off.
- Electrical safety approvals: copies of the electrical inspector clearance (CEIG, where your state and plant size require it), with its date and reference
- DISCOM approvals: net metering or grid synchronization letter and meter seal report
- Work-at-height rules and roof access routes, with the roof access authority named
- Shutdown procedure, written step by step: which breakers to open in order, DC isolation, lock-out and tag-out points, and how to restart
- Single line diagram with isolation points marked, posted at the site
- Handed-over spares list: fuses, MC4 connectors, SPDs and spare modules, with quantities and storage location
Titles vary by DISCOM and state, so this article does not quote one state’s official document names. Instead, file each approval under the exact heading printed on the letter, and add the issuing DISCOM office, reference number and date. A sensible filing record looks like this:
| Document (as titled by your DISCOM) | Details to record |
|---|---|
| Net metering or grid synchronization approval | Issuing office, reference number, date, sanctioned capacity |
| Meter seal report | Meter serial number, seal numbers, date |
| Electrical inspector clearance (CEIG, if applicable) | Reference, date, plant size covered |
Spare modules should come with the same batch details, since mismatched modules cause string imbalance later. Ask your state electrical inspectorate or DISCOM which approvals apply to your plant.
How Should an EPC Run the Handover Meeting?
Run a joint site walkdown with EPC, owner and O&M present, check each checklist item against the physical plant, and record gaps in a signed punch list with owners and dates. Do not close the handover until critical items are cleared.
Sample Punch List Entry
| No. | Gap found | Severity | Owner | Due | Status |
|---|---|---|---|---|---|
| 1 | String map missing inverter 2 MPPT labels | Critical | EPC design lead | Before sign-off | Open |
| 2 | Combiner box 3 label faded | Minor | EPC site engineer | Agreed period after sign-off | Open |
Use a simple rule: critical items (single line diagram, warranties, monitoring access, baselines) block sign-off. Minor items, such as a missing label, can follow within an agreed period. What is not settled industry-wide is how long the EPC should support the O&M team after sign-off; 30 to 90 days is common practice, but it is a contract choice, not a rule.
The wider shift is toward EPCs acting as long-term partners rather than one-day installers. That is why a clean handover pays back. If you outsource O&M, read the playbook for outsourcing O&M after handover.
FAQ
Who owns the handover documents?
The plant owner owns them. The EPC prepares and delivers the pack, and the O&M provider receives a copy to work from.
When should baseline readings be taken?
At commissioning, in clear sun, before the plant is accepted. Repeat at the first quarterly visit to confirm nothing has drifted.
What if the EPC cannot supply as-built drawings?
The O&M team can survey the plant and redraw them, but the cost should be agreed with the EPC before handover closes.
Start With a Cleaner Handover
Intello takes over plants with this pack and builds the monitoring and maintenance plan around it. To discuss a handover for your next project, request a quote. Existing customers can use the Intello portal login, and you can read about the team on the Intello about page.
