This review provides an in-depth analysis of photovoltaic (PV) module failure and degradation mechanisms, focusing on their causes and detection techniques. The study highlights that despite PV modules being considered reliable, failures and extreme degradations can occur, often due to factors such as manufacturing defects, harsh weather conditions, and environmental stressors. The paper reviews the literature to examine the types of failures, their root causes, and the hazardous consequences they can have on PV systems. It emphasizes the importance of electrical characterization techniques for detecting failures and degradation, and identifies the most common degradation processes. The review also discusses the impact of failures on safety and energy loss, and the potential for catastrophic events such as fires. It outlines the classification of PV failures based on severity, occurrence time, and location, and highlights the need for further research into corrective actions and solutions. The study concludes that early detection and proactive maintenance are crucial for ensuring the reliable and safe operation of PV systems.This review provides an in-depth analysis of photovoltaic (PV) module failure and degradation mechanisms, focusing on their causes and detection techniques. The study highlights that despite PV modules being considered reliable, failures and extreme degradations can occur, often due to factors such as manufacturing defects, harsh weather conditions, and environmental stressors. The paper reviews the literature to examine the types of failures, their root causes, and the hazardous consequences they can have on PV systems. It emphasizes the importance of electrical characterization techniques for detecting failures and degradation, and identifies the most common degradation processes. The review also discusses the impact of failures on safety and energy loss, and the potential for catastrophic events such as fires. It outlines the classification of PV failures based on severity, occurrence time, and location, and highlights the need for further research into corrective actions and solutions. The study concludes that early detection and proactive maintenance are crucial for ensuring the reliable and safe operation of PV systems.