A combiner box, also known as a combiner panel or PV combiner box, is an electrical device used in solar energy systems (photovoltaic or PV systems). The purpose of the combiner box is to combine the direct current (DC) produced by solar panels and direct it to a common point before it goes to the inverter.

In a typical solar power system, there are multiple solar panels, each producing direct current. The combiner box is usually installed near the solar panels and contains fuses or switches to control the current of the individual solar panels. The box also has a DC output connected to the inverter, which converts the direct current into alternating current (AC) for use in the grid or in a local electrical system.