Quality and safety on every solar site

Safety is supervised daily

A safe site is a productive site. These six practices apply on every Solunar site, every working day.

• Dedicated safety supervisorPresent at every site, every working day.
• Mandatory PPE for every workerHelmets, reflective jackets and safety shoes.
• Daily toolbox safety talksA short safety briefing before work starts.

• Safety induction for every workerEvery new worker is inducted before starting work.
• First-aid kit on every siteKept ready at the site office for immediate care.
• Barricading around excavationsOpen trenches and pits are marked and barricaded.

Electrical tests before commissioning

These pre-commissioning tests prove that the plant is safe to energise and will generate as designed.

Electrical test 1

Insulation resistance (megger) test

A high test voltage is applied to cables and strings to check that the insulation is healthy and there is no leakage to earth.

Why

Damaged insulation causes earth faults, inverter trips and fire risk.

Reference

IEC 62446-1 (international standard for PV system testing)

Acceptance

At least 1 MΩ, tested at 500 V, 1,000 V or 1,500 V DC depending on system voltage (IEC 62446-1). Healthy new cables usually read in hundreds of MΩ, so any unusually low reading is investigated. Where the project sets a higher value, we test to that.

Electrical test 2

String open-circuit voltage and polarity test

Each string is checked for correct polarity and its open-circuit voltage (Voc) is measured before connection to the inverter.

Why

Reversed polarity can damage inverters. Wrong Voc shows a missing or faulty module.

Reference

IEC 62446-1

Acceptance

Voc close to the expected value after temperature correction. Strings in the same group should be within about 5% of each other.

Electrical test 3

Earth resistance test

The resistance of the earthing system is measured to make sure fault current and lightning have a safe path to the ground.

Why

Good earthing protects people and equipment.

Reference

IS 3043:2018 (code of practice for earthing)

Acceptance

Below 1 ohm for the main earth grid, the value most utility-scale solar specifications ask for, or lower if specified.

Electrical test 4

IV curve tracing

An IV curve tracer measures the full current and voltage curve of each string and compares it with the expected curve.

Why

Finds shading, mismatch, damaged modules and wiring issues that simple tests miss.

Reference

IEC 62446-1, Category 2 tests

Acceptance

Curve shape and power close to expected values at standard conditions. Abnormal strings are checked and fixed.

Electrical test 5

Thermography (infrared inspection)

A thermal camera scans modules, connectors and combiner boxes while the plant is generating.

Why

Hotspots show faulty cells, loose connections and failing diodes before they cause damage.

Reference

IEC TS 62446-3 (outdoor infrared thermography of PV plants)

Acceptance

Hotspots of about 10 °C or more above neighbouring areas are investigated and fixed.

Electrical test 6

Inverter and SCADA commissioning checks

Inverters, protection settings and monitoring signals are checked together before the plant is handed over.

Why

Confirms the plant runs, protects itself and reports data correctly.

Reference

Manufacturer procedures and project specification

Acceptance

All inverters, alarms and monitoring signals working and recorded.

The standards and values above are common references. The exact tests and acceptance values for each solar project are set by its technical specification. Tests are carried out by our team or through third-party laboratories, as the project requires.