What it is: A solar combiner box (also called a PV combiner box or DC combiner box) is an electrical enclosure that collects DC output from multiple solar panel strings, combines them onto a common busbar, and routes the combined power to the inverter — while providing overcurrent. What it is: A solar combiner box (also called a PV combiner box or DC combiner box) is an electrical enclosure that collects DC output from multiple solar panel strings, combines them onto a common busbar, and routes the combined power to the inverter — while providing overcurrent. This Amonix system in Las Vegas, US, consists of thousands of small Fresnel lenses, each focusing sunlight to ≈500x higher intensity onto a tiny, high-efficiency multi-junction solar cell. A Tesla Roadster is parked beneath for scale. Concentrator photovoltaics (CPV), also called concentrating. DC Combiner Boxes for photovoltaic systems The DC Combiner Box collects and distributes the string currents from the solar panels. Available in 1-in to 6-in string configurations.