IEC TS 62446-3-2017 PDF

Full title and description

Photovoltaic (PV) systems - Requirements for testing, documentation and maintenance - Part 3: Photovoltaic modules and plants - Outdoor infrared thermography. This technical specification defines procedures and minimum requirements for performing outdoor infrared (thermographic) inspections of PV modules and plants in operation to support preventive maintenance, fire-safety checks and assessment of module quality.

Abstract

IEC TS 62446-3:2017 specifies the requirements for measurement equipment and environmental conditions, the inspection and imaging procedure (including use of fast carriers such as drones), evaluation and software considerations, classification of thermal abnormalities and reporting, plus personnel qualification criteria and annexed guidance material. It is intended as a guideline to carry out reproducible outdoor thermographic surveys of PV installations.

General information

• Status: Published (Technical Specification).
• Publication date: 15 June 2017.
• Publisher: International Electrotechnical Commission (IEC), TC 82 (Solar photovoltaic energy systems).
• ICS / categories: 27.160 (Solar energy engineering).
• Edition / version: Edition 1.0 (2017).
• Number of pages: 37 pages.

Scope

Specifies outdoor thermographic inspection of PV modules and associated plant components while in operation. Covers minimum instrument performance (IR camera and photographic documentation), required ambient/meteorological conditions, imaging geometry and procedures, image evaluation methods including projection to nominal irradiance, classification of thermal abnormalities, and minimum content for inspection reports. Also includes normative annexes on geometric resolution, personnel qualifications and a matrix for module thermal abnormalities.

Key topics and requirements

• Minimum performance requirements for IR cameras used on PV plants (sensitivity, resolution and geometric considerations).
• Requirements for photographic documentation and instruments to record ambient conditions (irradiance, wind, temperature).
• Environmental and operational acceptance criteria for imaging (irradiance, wind speed, cloud cover/instability, time of day).
• Imaging procedures and best practices, including handling of moving platforms (drones) and emissivity considerations.
• Software/evaluation methods, image processing, and projection of observed temperature differences to nominal irradiance.
• Classification matrix for thermal abnormalities and guidance on interpreting module-level defects and BOS component hot-spots.
• Minimum content for inspection reports and recommended qualifications for thermography personnel.

Typical use and users

Used by PV plant operators, O&M providers, independent inspection bodies, thermography technicians, system designers, insurers and safety authorities for preventive maintenance, fire-risk assessment, warranty and quality checks, and performance troubleshooting of rooftop and ground-mounted PV systems.

Related standards

Part of the IEC 62446 series addressing testing, documentation and maintenance of PV systems. Relevant related documents include IEC 62446-1 (Part 1: grid-connected systems — documentation, commissioning tests and inspection, 2016) and IEC 62446-2 (Part 2: maintenance of PV systems, 2020). Ongoing revisions and project work for second editions of parts of the 62446 series (including an ED2 for 62446-3) have been reported in IEC project listings.

Keywords

PV, photovoltaic, thermography, infrared inspection, IR camera, maintenance, O&M, thermal abnormalities, emissivity, drones, inspection report, IEC 62446, TC 82.

FAQ

Q: What is this standard?

A: IEC TS 62446-3:2017 is a technical specification that defines requirements and recommended procedures for outdoor infrared (thermal) inspection of photovoltaic modules and plants in operation.

Q: What does it cover?

A: It covers equipment requirements (IR and photo cameras), acceptable environmental conditions, imaging and evaluation procedures (including use of aerial carriers), software/evaluation methods, classification of thermal anomalies, reporting, and personnel qualification. Normative annexes provide additional measurement and evaluation guidance.

Q: Who typically uses it?

A: Plant operators, operation & maintenance contractors, certified thermographers and inspection bodies, system designers, insurers and safety/regulatory inspectors use the specification for preventive maintenance, warranty checks and safety risk assessment.

Q: Is it current or superseded?

A: The document was published in June 2017 and remains the published Technical Specification (Edition 1.0); IEC project listings indicate work toward an ED2 (a revision) has been underway with project activity recorded in 2025, so users should check for a newer edition or amendments when planning work.

Q: Is it part of a series?

A: Yes — it is Part 3 of the IEC 62446 series (requirements for testing, documentation and maintenance of PV systems). Other parts include IEC 62446-1 (commissioning, documentation and inspection) and IEC 62446-2 (maintenance).

Q: What are the key keywords?

A: Key keywords include photovoltaic, PV systems, thermography, infrared inspection, IR camera, thermal anomalies, maintenance, inspection report, emissivity and TC 82.