In photovoltaic (PV) systems, the combiner box plays a critical role by consolidating multiple DC strings and feeding the combined output to an inverter. The material of its enclosure directly impacts system safety, service life, and maintenance costs. The two mainstream options on the market are metal enclosures (typically galvanized steel or stainless steel, commonly referred to as "metal boxes") and non-metallic enclosures (typically PC/ABS engineering plastics, commonly referred to as "plastic boxes"). Below is a comprehensive comparison across multiple technical dimensions.