Solar & Photovoltaic Systems Inspection

Per EN 62548 Clause 4, the mounting system must be designed to support the PV array under all environmental loads including wind, snow, and dead loads per EN 1991-1-3 and EN 1991-1-4. The structural capacity of the roof or ground structure must be verified to carry the additional load of the PV system. Mounting fixings must be compatible with the roof covering material and must maintain the weatherproof integrity of the roof. All metallic components must be corrosion-resistant or protected to a standard suitable for the expected service life of at least 25 years.

1. Verify that a structural assessment has been carried out confirming the roof or structure can support the PV array under all load combinations per EN 1991

2. Inspect mounting rails and brackets for correct type, spacing, and secure fixation to the supporting structure per the mounting system design

3. Check that roof penetrations are properly sealed and flashed to maintain weatherproofing and comply with the roof covering warranty

4. Confirm mounting system components are corrosion-resistant (stainless steel, anodised aluminium) and compatible to avoid galvanic corrosion

5. Verify that module clamp positions are within the zones specified by the module manufacturer for mid and end clamps

- Structural assessment not carried out, particularly on older buildings with limited roof load capacity

- Roof penetrations poorly sealed, leading to water ingress at mounting bolt locations

- Dissimilar metals in contact (e.g., aluminium rails with plain steel bolts) causing galvanic corrosion

- Module clamps positioned outside the manufacturer's specified zones, reducing wind uplift resistance

Per EN 62548 Clause 5, PV modules must comply with IEC 61215 (crystalline) or IEC 61646 (thin-film) for design qualification and IEC 61730 for safety qualification. Modules must be installed in accordance with the manufacturer's installation instructions, including orientation, tilt angle, and ventilation clearances. Module labels must be legible and data plate information must match the system design documentation. Modules must be handled and installed without mechanical damage to cells, frames, junction boxes, or cables.

1. Verify each module carries IEC 61215 or IEC 61646 type approval and IEC 61730 safety certification markings

2. Confirm module orientation and tilt angle match the system design specification for optimal energy yield

3. Inspect modules for visible damage including cracked cells, delamination, snail trails, frame damage, or junction box cracks

4. Check that adequate ventilation gaps are maintained between modules and the roof surface per the manufacturer's requirements

5. Verify that module data plate values (Voc, Isc, Pmax) match the system design documentation and string calculations

- Modules installed with insufficient ventilation gap, causing overheating and reduced output and lifespan

- Mechanical damage to module cells during installation from foot traffic or improper handling

- Module labels facing inaccessible directions, making future identification and fault-finding difficult

- Mismatched modules within the same string causing mismatch losses and potential hotspot formation

Per EN 62548 Clause 7, DC cables must be double-insulated or equivalent (PV1-F type per EN 50618) and rated for the maximum system voltage including the cold-temperature Voc. Cable sizing must account for current-carrying capacity and voltage drop per EN 62548 Clause 7.3. DC connectors must be of the same manufacturer and type on both mating halves per EN 62548 Clause 7.2 — mixing connector brands is prohibited. String cables must be routed and secured to prevent mechanical damage, UV degradation, and heat exposure.

1. Verify DC cables are PV1-F type per EN 50618 or equivalent double-insulated solar cable rated for the system voltage

2. Check that cable sizing is adequate for the string current with appropriate derating and voltage drop per EN 62548 Clause 7.3

3. Inspect all DC connectors to confirm the same manufacturer and type are used on both mating halves — no mixed brands

4. Verify DC cables are properly routed, secured with UV-resistant clips at maximum 300 mm intervals, and protected from sharp edges

5. Confirm string polarity is correct and string open-circuit voltages are within expected range before connection to the inverter

- Mixed DC connector brands used on mating halves, creating increased resistance and potential arc-fault risk

- DC cables left unsupported and hanging loosely, subject to wind-induced abrasion and UV degradation

- Cable insulation damaged by sharp roof edges or cable ties that are too tight

- String voltage calculations not accounting for cold-temperature conditions, risking exceeding inverter maximum input voltage

Per EN 62548 Clause 8, inverters must comply with EN 62109-1 and EN 62109-2 for safety requirements. The inverter must be installed in a location with adequate ventilation to dissipate heat, protected from direct sunlight, rain, and dust as appropriate for its IP rating. DC and AC isolation switches must be provided per EN 62548 Clause 7.5. The inverter's input voltage and current ratings must be compatible with the string configuration. Anti-islanding protection must comply with EN 50549-1 for grid-connected systems.

1. Verify inverter certification per EN 62109-1 and EN 62109-2 and confirm the model matches the system design specification

2. Check that the inverter is installed in a well-ventilated location within the temperature range specified by the manufacturer

3. Confirm DC isolator is installed between the PV array and inverter, and AC isolator is installed between the inverter and grid connection

4. Verify the string configuration (Voc at minimum temperature and Isc) is within the inverter's input window per the manufacturer's datasheet

5. Confirm anti-islanding protection is configured and functional per EN 50549-1 for the grid connection requirements

- Inverter installed in direct sunlight or poorly ventilated enclosures, causing thermal derating and reduced output

- DC isolator not rated for the maximum string voltage under cold-temperature conditions

- String configuration exceeding the inverter maximum input voltage, risking damage to the inverter

- Anti-islanding settings not correctly configured for the local grid operator's requirements

Per EN 62548 Clause 9 and HD 60364, the AC connection between the inverter and the distribution board must comply with standard low-voltage installation requirements. Cable sizing must account for the inverter maximum output current, installation method, and voltage drop per HD 60364-5-52. Overcurrent protection must be provided per HD 60364-4-43. The connection must be on the supply side of the main RCD or on a dedicated circuit with its own RCD per the grid operator's requirements. Generation metering must be installed where required.

1. Verify AC cable sizing is adequate for the inverter maximum output current including derating factors per HD 60364-5-52

2. Confirm overcurrent protection is correctly rated for the cable and inverter output per HD 60364-4-43

3. Check the point of connection at the distribution board and verify it meets the grid operator's connection requirements

4. Inspect generation meter installation and confirm it is correctly reading exported and generated energy

5. Verify correct labelling at the distribution board identifying the PV supply circuit per EN 62446

- AC cable undersized for the inverter maximum output, particularly on long cable runs with significant voltage drop

- Point of connection at the distribution board not agreed with the grid operator, causing compliance issues

- Distribution board not labelled to identify the PV supply, creating a hazard for personnel working on the board

- Generation meter not installed or not correctly configured to record total generation

Per EN 62548 Clause 6, all exposed metalwork of the PV system including module frames, mounting structures, and cable trays must be earthed per HD 60364-5-54. Where the building has a lightning protection system (LPS), the PV system must be integrated per EN 62305-3 and EN 62305-4. Surge protection devices (SPDs) must be installed on both the DC and AC sides per EN 62305-4 and EN 62548 Clause 6.4 where a risk assessment indicates they are required. Equipotential bonding of the PV system to the building LPS must be provided.

1. Verify all module frames and mounting metalwork are earthed with correctly sized bonding conductors per HD 60364-5-54

2. Check that earth connections use approved methods — star washers, serrated lugs, or dedicated earthing clips — not relying on anodised aluminium contact alone

3. Confirm SPDs are installed on the DC side (Type 2 minimum) and AC side where required by the risk assessment per EN 62305-4

4. Verify integration with the building lightning protection system per EN 62305-3, including separation distances or bonding as appropriate

5. Measure earth continuity of the PV system bonding network and confirm resistance is within acceptable limits

- Module frame earthing relying solely on anodised aluminium-to-aluminium contact, which provides inadequate conductivity

- SPDs omitted on the DC side, leaving the system vulnerable to lightning-induced surges

- PV system not integrated with the existing building lightning protection system, creating a risk of side-flashing

- Earth bonding conductors undersized for the prospective fault current

Per EN 62446-1, all PV systems must be tested and documented before handover. Required tests include continuity of earth bonding, string open-circuit voltage (Voc), string short-circuit current (Isc), string polarity, insulation resistance (minimum 1 MΩ per string at system voltage × 2 + 1000 V, or 500 V DC minimum), and functional testing of all protection devices. An as-built system documentation pack must be provided including string layouts, single-line diagrams, component datasheets, and all test results per EN 62446-1 Annex A.

1. Perform earth continuity tests on the entire bonding network including all module frames and mounting metalwork

2. Measure Voc and Isc for each string and verify values are within ±5 % of the expected values corrected for irradiance and temperature

3. Carry out insulation resistance tests on each string at the required test voltage per EN 62446-1 — minimum 1 MΩ

4. Perform functional tests of DC and AC isolators, SPDs, RCDs, and anti-islanding protection

5. Verify the complete documentation pack per EN 62446-1 Annex A including string layout, single-line diagram, datasheets, and all test certificates

- Insulation resistance below 1 MΩ due to moisture ingress at connectors or damaged cable insulation

- String Voc or Isc values outside expected range, indicating a faulty module, incorrect wiring, or shading issue

- Documentation pack incomplete, with missing string layouts or component datasheets

- Functional test of anti-islanding protection not performed or not documented