Module 4: Installation, Configuration & Commissioning

24 sept. 2026

Introduction

A correct design will fail if it is poorly installed. Many faults found on solar installations in Nigeria result from workmanship shortcuts: fixings that miss the structure, cables abraded by sharp edges, mismatched connectors and incorrect settings. This module sets out the standards of workmanship, configuration, testing and commissioning required of Installation Partners, and the reasons for them.

Learning outcomes

On completing this module, partners should be able to:

1. Prepare for an installation so that work is right first time;
2. Explain how mounting systems resist wind load and maintain weathertightness;
3. Route, terminate and label DC cables to a professional standard;
4. Select suitable locations for inverters and batteries, and connect parallel batteries correctly;
5. Connect AC supplies, including generators, without backfeed or incorrect earthing;
6. Install effective earthing and surge protection;
7. Configure equipment from approved information;
8. Inspect and test a system before energisation and interpret the results;
9. Commission a system by testing each operating mode;
10. Complete handover with accurate records and an informed customer;
11. Recognise and avoid common workmanship defects.

4.1 Preparation

Before travelling, the partner should study the approved design until it is fully understood, including equipment, string configuration, cable sizes, protection and equipment locations. Queries should be raised with EcoStride before the job. Tools and PPE should be checked (Module 2, unit 2.3) and roof work planned for suitable weather.

On delivery, each item should be checked against the design for model, rating and quantity, and inspected for damage such as cracked glass, dented battery casings or broken connectors. Indicators of counterfeit or non-conforming products include poor labelling, missing ratings, conductors thinner than marked and unusually light protective devices. Any discrepancy must be reported to EcoStride with photographs before installation.

Work should be sequenced so that circuits remain isolated until testing is complete: structure and modules; cabling with all circuits isolated; inverter and battery; protection and earthing; inspection and testing; energisation.

4.2 Mounting structures and roofs

Wind flowing over and under a module creates an upward force that can exceed the module's weight. This load passes through clamps and rails to the fixings. A fixing that engages only the roof sheet may tear out, transferring its load to adjacent fixings, which may then fail progressively.

A fixing that misses its support must be removed, relocated into the structure and the unused hole sealed by an approved method. Penetrations must be sealed with the washers and outdoor-rated sealant specified by the mounting system.

Modules must be clamped only within the manufacturer's permitted zones, and clamps and bolts tightened to the specified torque. The specified spacing between modules and rails allows for thermal expansion and ventilation. Aluminium must not be placed in direct contact with copper or plain steel, as galvanic corrosion results; the mounting system's matched fasteners should be used. Rails and frames must be bonded to earth by the method the mounting system specifies.

4.3 DC wiring, connectors and polarity

PV cable is double-insulated, UV-resistant and rated for high DC voltages; general building wire is not suitable. Cables move continually under wind and thermal cycling, and abrasion against sharp edges can penetrate insulation within months, causing shock, earth-fault or fire hazards. Cables must therefore be:

• fixed to the structure at short intervals with UV-resistant clips or ties;
• kept clear of the roof surface;
• protected at edges and entry points with grommets, conduit or glands;
• run with positive and negative conductors together to minimise loop area;
• formed into a drip loop before entering a building or enclosure;
• labelled at each end.

PV connectors from different manufacturers may appear to mate but differ in dimensions, materials and seals. The resulting contact resistance produces heat (P = I² × R), which can melt the connector and cause fire, while a poor seal admits water. Both halves of a connection must be from the same manufacturer and of the same type. Conductors must be stripped to the specified length, crimped with the tool and die designed for the connector, pull-tested, and sealed by tightening the rear nut.

A multimeter indicates the voltage of the red probe relative to the black probe. With red on the conductor marked positive, a positive reading confirms correct polarity; a negative reading indicates reversed or mislabelled conductors. The circuit must remain disconnected until the fault is traced and corrected. Reversed battery polarity can destroy an inverter's input stage instantly.

String fuses are required where three or more strings are connected in parallel, to protect a faulted string from the combined current of the others. DC isolators must be rated for the maximum string voltage and current.

4.4 Inverter and battery installation

Inverter losses are dissipated as heat: a 5 kW inverter at 95% efficiency produces about 250 W. Elevated temperatures shorten the life of electronics and batteries and cause inverters to reduce output. A suitable location:

• provides the manufacturer's minimum clearances for ventilation;
• is shaded and cool, and is not a closed cupboard or unventilated room;
• is dry and away from bathrooms, kitchens, water tanks and roof leaks;
• is away from fuel, gas cylinders and other combustible materials;
• allows safe operation and maintenance, with isolators within reach;
• is secure against theft, tampering and access by children;
• has a wall or floor capable of bearing the load.

Where a customer proposes an unsuitable location, the reasons should be explained and a suitable alternative agreed.

Parallel batteries

Current divides between parallel batteries in inverse proportion to the resistance of each path. If the inverter is connected to one end of the bank only, the nearest battery carries more current, cycles harder and ages sooner. Balanced current sharing is achieved by:

• busbars fed by cables of equal size and length to each battery; or
• cross (diagonal) connection, taking the positive from one end of the bank and the negative from the other;
• individual battery protection where the manufacturer requires it;
• BMS communication connected as the manufacturer specifies.

Battery fuses or breakers should be located as close to the battery as possible. Lugs must suit the conductor and be crimped with the correct tool, terminals tightened to the specified torque with a calibrated tool, and terminal covers refitted.

4.5 AC connections and multiple supplies

In a typical hybrid installation, the grid and often the generator supply the inverter's AC input, and the inverter's AC output supplies a dedicated distribution board for essential loads. Non-essential loads remain on the original board. This limits the inverter to its design load and allows backed-up circuits to be clearly labelled.

Generators must be connected only to the inverter's generator input where provided, or through an approved interlocked changeover. Grid and generator supplies must never be joined, and cables must never be transferred manually between supplies (Module 2, unit 2.11). The generator's output voltage, frequency and stability should be suitable for the inverter.

When the grid is disconnected, the inverter becomes the source for the backed-up circuits, and a correct neutral–earth connection must still exist for RCDs and earthing to function. Some inverters provide this internally in backup mode; others require an external arrangement. The manufacturer's instructions must be followed exactly: a missing link can prevent RCD operation, and an additional link can cause unwanted tripping or current in protective conductors.

On three-phase sites, loads must be balanced and the inverter configuration specified in the design used. A single-phase inverter output must never be connected across two phases.

4.6 Earthing and surge protection

Earth electrodes should be installed in ground that remains moist where possible, connected with a proper rod clamp and protected in an inspection pit to allow future testing. Electrode resistance must be measured with an earth tester and recorded. Dry, sandy or rocky ground may require longer or multiple electrodes to achieve the value required by the design.

Panel frames and rails are bonded using the mounting system's approved earthing clips or lugs, which penetrate the anodised finish. Inverters, battery racks and distribution boards are connected to the main earthing terminal with protective conductors of the specified size, and continuity is verified (unit 4.8).

DC SPDs are installed at the inverter PV input, and at the array where the design requires it for long cable runs. AC SPDs are installed at the distribution board as specified. SPD earth conductors must be short and straight, since additional length adds voltage during a surge. SPD status indicators should be checked; a device showing an operated indication must be replaced.

4.7 Configuration

Incorrect settings can cause overcharging or undercharging, BMS trips, wasted solar energy or unnecessary generator operation. Settings are taken, in order, from:

1. the approved design;
2. the inverter manual for the exact model and firmware;
3. the battery manufacturer's data and BMS requirements;
4. both manufacturers' compatibility information;
5. EcoStride technical instructions where questions remain.

Settings must not be copied from other installations, and lead-acid profiles must not be applied to lithium batteries; for example, equalisation charging used for flooded lead-acid batteries can overcharge lithium cells.

Firmware should be checked against the manufacturer's or EcoStride's recommendation before configuration. Final settings are recorded and each settings screen photographed for the job report.

4.8 Inspection and testing

IEC 62446-1 sets out the inspection and tests to be completed before a PV system is put into service.

Visual inspection confirms that the structure is secure and fixed to supports, penetrations are sealed, cables are supported, protected and labelled, connectors are matched and fully mated, protective devices are of the correct type and rating, earthing and bonding are present, clearances are maintained and warning labels are fitted.

String current should be measured with a DC clamp meter during operation or with equipment and a method approved for the purpose. A string must never be short-circuited with a conductor.

Worked example: interpreting string Voc

A string of four modules has a datasheet Voc of 49.6 V and a Voc coefficient of −0.27 %/°C. Cell temperature at the time of measurement is 35 °C, 10 °C above STC. Expected Voc per module is 49.6 × (1 − 0.027) ≈ 48.3 V, and for the string approximately 193 V.

4.9 Commissioning

The system is energised in the sequence specified by the manufacturer. The display and any abnormal sound or smell are monitored, and energisation is stopped if anything is abnormal.

Each operating mode used by the design is then tested:

1. PV generation and maximum power tracking;
2. battery charging from PV, and from grid or generator where designed;
3. battery supply to loads;
4. transfer to battery on loss of grid supply, within the specified transfer time;
5. reconnection on restoration of grid supply;
6. generator operation, without backfeed to the grid;
7. operation of the customer's actual loads, including motor starting.

The following are recorded: PV voltage and current per MPPT input; battery voltage, current, SoC and BMS communication status; AC input and output voltage and frequency; and confirmation that monitoring is operational. After a period under load, connections are checked for abnormal temperature using an infrared thermometer or thermal camera where available. These baseline readings form part of the job report and are the reference for future fault-finding.

4.10 Handover

Labelling

Durable labels are required to identify each isolator and protective device; to warn that PV conductors remain live in daylight; to warn at the distribution board that circuits may be supplied by the inverter when the grid is off (dual supply); and to state the emergency shutdown sequence at the inverter.

Records

The job report should enable EcoStride to understand the installation without a site visit. It includes photographs of the array, fixings, cable routes, connections, inverter, battery, distribution board, labels and earthing; test results and baseline readings; final settings; serial numbers of principal equipment for warranty purposes; any approved deviation from the design; and any outstanding task with an agreed completion plan.

Customer instruction

The customer is instructed as described in Module 1, unit 1.7, and asked to demonstrate their understanding.

4.11 Common workmanship defects

Before reporting a job as complete, the partner should inspect the whole installation as an EcoStride auditor would.

Case studies

The following cases are based on situations commonly encountered on Nigerian sites. Names and places are illustrative.

Case 1: Fixings into sheeting. Several brackets on a 20-module array in Calabar were fixed only into the roof sheet. In the first severe storm a row lifted and tore the sheet, and rain entered the building for a week. Principle: unit 4.2.

Case 2: Mixed connectors. A customer in Benin City reported a burning smell from the roof. A connector formed from two different brands had overheated through contact resistance over eight months and melted. Principle: unit 4.3.

Case 3: Unequal battery connection. A bank of four lithium batteries in Abuja was connected to the inverter at one end only. After a year, the nearest battery's capacity had fallen well below the others and its BMS tripped under heavy load. Principle: unit 4.4.

Case 4: Pre-energisation test. Before energising a system in Ilorin, a partner measured a string Voc of about half the expected value and found one module connected in reverse. The fault was corrected in ten minutes, before any damage occurred. Principle: unit 4.8.

Relationship to performance rating

Practical activities

1. Crimp PV connectors with the correct tool, pull-test them, and section one to inspect the crimp.
2. On an accessible metal roof, identify the lines of the supporting structure from the fixing pattern.
3. Practise identifying polarity on a battery or string, including interpreting a reversed reading.
4. Calculate the expected Voc of a string at the prevailing cell temperature, measure it and compare.
5. In any hybrid inverter manual, locate the settings for battery type, charge voltage, maximum charge current and source priority.
6. Inspect an existing installation against the table in unit 4.11 and record each defect and the correct practice.

Glossary