Field-Based Evaluation of Small-Scale Photovoltaic Systems: Compliance and Installation Practices in Finland

This study evaluates the compliance of small-scale photovoltaic (PV) installations in Finland, focusing on 60 small-scale systems primarily installed between 2022 and 2024. The inspected systems were mainly located in detached houses, with participation based on voluntary recruitment. Using a systematic, field-based inspection methodology, the study examines adherence to standards throughout the installation process, including system design, installation practices, commissioning inspections, and documentation. Beyond identifying deficiencies, the analysis investigates installers’ practices and interpretations of regulatory requirements. The findings reveal substantial variability in compliance, with only a small fraction of systems meeting all mandatory requirements. Common deficiencies include incomplete or missing commissioning inspection reports, inadequate system labeling, and deviations in safety-critical practices such as equipotential bonding. These issues emphasize the need for clearer guidance, enhanced installer training, and stricter oversight to ensure consistent adherence to standards. By offering a detailed evaluation of compliance challenges and highlighting examples of best practices, this study contributes to the development of safer, more reliable PV systems. It provides valuable insights for regulators, installers, and property owners, emphasizing the importance of standardization and professional expertise in supporting the successful adoption of PV technologies.