Solar Commissioning Checklist: Tests, Documents and Handover

A PV system can be wired exactly to the drawing and still fail the first time it is switched on. Commissioning catches those faults before the owner does. This page is a working checklist you can print and tick off on site.

Last updated: November 2026. Test values come from a utility guideline that applies IEC 62446-1, read on 28 October 2026.

Commissioning is the set of checks that prove a solar system is built as designed, safe to switch on, and ready to hand over. This page is a checklist in seven phases. For the order of work and the sign-off steps, read our solar commissioning protocol. This page is the list of checks. That page is the procedure.

The seven phases in one line each

1. Paperwork and safety. Get the approved plans, the single line diagram (SLD, a simple drawing of how the system is wired) and the safety plan.
2. Visual inspection. Check the build, the labels and the fire measures before you power anything.
3. DC tests. Test earth continuity, polarity, string voltage, string current and insulation resistance.
4. AC and grid checks. Test the AC circuit and the grid protection.
5. Inverter start-up. Follow the maker’s steps, then check settings and monitoring.
6. Performance and heat checks. Measure performance ratio, and scan for hot spots.
7. Handover. Give the owner the records, labels, warranties and training.

Phase 1: Paperwork and safety

• Approved plans, permits and grid approval are on site.
• The SLD matches what was built. Update it for any field change.
• Datasheets and manuals for every main part are on site.
• A safety plan names the risks on site. SEC asks for a safety form before inspectors visit.
• The tester has instruments rated for the circuit’s voltage and current.

PV is live in daylight. SEC notes that work on a PV array counts as work under voltage. Short both module connectors, or keep the module connectors and the string breaker open, while you work.

Phase 2: Visual inspection

SEC says inspection comes before testing, and normally before you energize the system.

• Modules, frames and mounts show no damage. Roof fixings and cable entries are weatherproof.
• The DC system suits the site’s wind, heat, dust and corrosion.
• The highest array voltage suits the chosen inverter and site.
• Earthing and bonding conductors are fitted as designed.
• Surge protection is in place where the design asks for it.
• Fire measures follow your local code. Rules differ by country, so see our guide to fire safety setback rules by country.

Labels and signs

SEC’s list of labels to check includes these:

• Every circuit, device, switch and terminal is labeled.
• Combiner boxes carry a warning that parts inside may stay live after isolation.
• The AC isolation point is clearly labeled.
• Dual-supply warnings are at the point of connection.
• The SLD, inverter protection settings, installer details and shutdown steps are displayed on site.
• All signs are fixed and durable.

Phase 3: DC tests

Run the tests in this order. SEC says that if a test finds a fault, you fix it and then repeat the earlier tests.

SEC says an I-V curve test is an accepted way to get both Voc and Isc, so you can skip the separate tests. An I-V curve is a graph of a string’s voltage against its current. See our glossary entry on the I-V curve.

Open circuit voltage: the expected value

The expected Voc depends on cell temperature. A module’s temperature coefficient tells you how much.

Voc at temperature T = Voc(STC) × [1 + βVoc × (T − 25)]

Here STC means standard test conditions, and βVoc is the Voc temperature coefficient from the datasheet. It is a negative number. The numbers below are an example, not a datasheet:

• Module Voc(STC) 40 V, βVoc −0.30% per °C, cell temperature 45 °C. Expected Voc = 40 × [1 + (−0.003 × 20)] = 40 × 0.94 = 37.6 V per module.
• Same module at −10 °C: 40 × [1 + (−0.003 × −35)] = 40 × 1.105 = 44.2 V per module. In a 20-module string that is 884 V. This must stay below the inverter’s maximum DC input voltage on its datasheet.

Insulation resistance: minimum values

SEC’s Table 2, taken from IEC 62446-1, sets the test voltage and the minimum resistance. System voltage here means Voc(STC) × 1.25.

Two examples, with modules of 40 V Voc(STC):

• 20 modules in series: 20 × 40 = 800 V. Then 800 × 1.25 = 1,000 V, which is above 500 V. Test at 1,000 V. The minimum is 1 MΩ.
• 8 modules in series: 8 × 40 = 320 V. Then 320 × 1.25 = 400 V, which is in the 120 V to 500 V row. Test at 500 V. The minimum is 1 MΩ.

For arrays up to 10 kWp, measure the whole array. For arrays above 10 kWp, test single strings, or groups of strings that total no more than 10 kWp. Take surge protectors out of the circuit first if they could change the result. SEC suggests a wet insulation test when a result is doubtful.

Systems with optimizers or microinverters

Module-level electronics change the test plan. SEC’s Table 1 says:

Phase 4: AC and grid checks

• Insulation resistance test of the AC circuit, as IEC 60364-6 asks.
• Interface protection settings match what your utility requires. SEC checks the settings, thresholds and times.
• The interface device disconnects the system when the grid power fails.
• After power returns, the interface device reconnects.
• If the site must limit export, test that the limit works and that the meter reads in the right direction.
• In the US, check the rapid shutdown rule in NEC 690.12 for the code edition your authority uses (NFPA lists 2026 as the current edition of NFPA 70 and 2023 as the one before it). See our entry on rapid shutdown.

The exact trip values come from your utility’s grid code. We do not give them here because they differ by country.

Phase 5: Inverter start-up and monitoring

• Follow the inverter maker’s start-up steps. SEC says to test inverters as the maker defines.
• Set the grid country code and grid settings as your utility requires.
• Confirm the string voltages sit inside the inverter’s input window, including at the coldest expected cell temperature.
• Check that the monitoring system records output, and irradiance and temperature if sensors are fitted.
• Test alarms and the remote alert.
• Test remote access from off site.

For more on inverter records, see our inverter commissioning data record.

Phase 6: Performance and heat checks

Performance ratio (PR)

Performance ratio compares the energy a system made with the energy it should have made. IEC 61724-1 defines it as PR = Yf ÷ Yr. Yf is the final yield (kWh made per kWp installed). Yr is the reference yield (the sun energy on the array, in kWh per m², divided by 1 kW per m²).

Example for one day: a 10 kWp system makes 49.2 kWh. The sun energy on the array is 6.0 kWh/m².

• Yf = 49.2 ÷ 10 = 4.92 hours
• Yr = 6.0 ÷ 1 = 6.0 hours
• PR = 4.92 ÷ 6.0 = 0.82, or 82%

Hot modules lower PR, so PR is lower in summer. SEC explains that a temperature-corrected PR removes much of this. In the STC version, the power rating at each time step is adjusted by Ck = 1 + γ × (Tmod − 25 °C), where γ is the power temperature coefficient and Tmod is the module temperature.

How long is the test, and what is a pass?

Your contract sets both. SEC gives one example for test length:

SEC’s guideline sets no PR pass or fail value for its commissioning test. If your EPC contract names a PR target, use the contract’s test method. See also our solar performance ratio guide.

I-V curve tests

SEC says to measure string performance at stable irradiance of at least 400 W/m² in the plane of the array. To refer results to STC, use at least 800 W/m².

Thermal (infrared) scan

An infrared camera finds hot spots from bad cells, failed bypass diodes, poor connections and open strings. SEC’s method:

• Run the array in normal operation.
• Scan in steady light, ideally above 600 W/m² in the plane of the array.
• Scan every module, and look closely at junction boxes and connections.
• Compare each hot spot with its neighbors. A fixed temperature limit is not useful, because array temperature changes through the day.
• Mark each hot spot on the layout drawing and find the cause.

IEC TS 62446-3 sets the rules for outdoor thermography.

Shade record

SEC suggests recording the as-built shade as a baseline. It helps later if the shade changes or a performance guarantee is in dispute. See our shadow analysis page for how shading is modeled at the design stage.

Phase 7: Handover

The owner or O&M team should receive:

• As-built drawings and the updated SLD.
• Test reports with dates, instruments and results. SEC’s report list includes the test engineer, the site, the checks of interface protection and monitoring, and any change from the test plan.
• Datasheets, serial numbers and warranty papers.
• The grid approval and the final electrical inspection certificate. Some regions call it a CFEI. See what a CFEI is.
• Inverter settings, including protection settings, and monitoring log-ins.
• Shutdown and emergency steps, shown on site.
• The performance baseline and the shade record.
• A signed record that the owner’s staff were trained.

Store the records in a shared place, not on one laptop.

Provisional and final acceptance (PAC and FAC)

Many commercial EPC contracts use two certificates. The names and the timing come from your contract, so check yours.

Common failures and how to avoid them

Good string design can remove some DC test failures before the tester arrives.

After commissioning

The baseline you record now is the reference for later checks. Keep the PR result, the string readings and the monitoring set-up where the O&M team can find them. Set alerts for lost communication, a falling PR against your baseline, and a string that drifts from its neighbors. For more, read our guides to solar monitoring and the solar O&M business.

For the upstream steps, see our guides to panel installation and ground-mount design. For project milestones, see NTP, PTO and COD. To see how SurgePV supports the design stage that feeds this checklist, book a demo.

Source

• Saudi Electricity Company, Sustainable Integration of Renewable Energy Sources (Solar PV) with SEC Distribution Network: Inspection and Testing Guidelines, Version 2, read 28 October 2026. It is a utility guideline for small-scale PV in Saudi Arabia. It applies IEC 62446-1, IEC 61724-1, IEC 60364-6 and IEC TS 62446-3.

Frequently Asked Questions

What is a solar commissioning checklist?

A solar commissioning checklist is a list of checks that prove a PV system is built as designed, safe to switch on and ready for handover. It covers paperwork, inspection, DC tests, AC and grid checks, inverter start-up, performance and heat checks, and the handover records.

What standards apply to solar commissioning?

IEC 62446-1 covers documentation, commissioning tests and inspection for grid-connected PV. IEC 61724-1 covers performance monitoring and performance ratio. IEC TS 62446-3 covers outdoor thermography. Your local electrical code and your utility’s grid rules also apply. In the US that includes the NEC rules your authority uses.

What is the minimum insulation resistance for a PV array?

The Saudi Electricity Company guideline, which applies IEC 62446-1, gives 0.5 MΩ for system voltage below 120 V (test at 250 V), 1 MΩ for 120 V to 500 V (test at 500 V), and 1 MΩ above 500 V (test at 1,000 V). System voltage means Voc at STC multiplied by 1.25.

Which DC tests do you run during commissioning?

The basic DC tests are earth and bonding continuity, polarity, the combiner box test, string open circuit voltage, string current, functional tests and insulation resistance. An I-V curve test can replace the separate Voc and Isc tests.

What is the difference between PAC and FAC?

A Provisional Acceptance Certificate (PAC) is issued when the commissioning tests pass and the plant is running. A Final Acceptance Certificate (FAC) is issued after the defects period in the contract ends. Names and timing come from your contract.

Is there a minimum performance ratio for sign-off?

The contract sets it. The Saudi Electricity Company guideline gives no PR pass or fail value for its commissioning test. If your contract names a PR target, use the test method the contract names.

How long does a performance test last?

It depends on the rule you follow. One example is the Saudi Electricity Company guideline: at least one valid measurement up to 11 kW, one day with 99% valid data above 11 kW and up to 100 kW, and at least 10 days with 95% valid data above 100 kW.