Statistical Failure Analysis of 6000 Residential Rooftop-Harvested Photovoltaic Connectors

Photovoltaic (PV) connectors, which link modules in series and connect PV strings in parallel, have increasingly been recognized as a primary contributor to PV system failures and a source of numerous fire incidents. However, publicly available data on the rates and types of connector failures are scarce, primarily due to the proprietary nature of the information and the need for comprehensive analysis. This study represents the first large-scale investigation of harvested PV connectors, drawing from a dataset of 6,300 connectors from residential rooftop solar systems across the United States. The outcome of this work is twofold: 1) we have established a rapid characterization method for large populations of harvested connectors, incorporating visual inspection, resistance measurements, and x-ray imaging; and 2) the analysis made possible by our rapid-processing method has revealed, for a population of connector types provided by a single rooftop installer, failure statistics and insights for various connector makes and models, installation practices, climate zones, manufacturing dates, and system configurations. The x-ray data reveal critical information regarding internal component failures that lead to pin/socket displacement and highlight the implications for variable pin/socket engagement. This research identifies common failure modes that could be considered in future connector designs standards, and operations and maintenance practices, to ultimately improve the reliability of this vital component of PV infrastructure.