Combiner boxes are designed for safe and code compliant PV installations. They combine the output of multiple solar electric (PV) source circuits.
Use a combiner boxes when multiple strings of modules have to be parallel connected. For example, the Outback combiner box can handle up to 12 strings up to 140 DC voltages or 7 touch safe fuses up to 600 Volts DC.
Combiner boxes are designed for installation near the PV array with each series string of solar modules connected to one of the fused/breaker circuits. The solar array input strings may be combined, yet only a single pair of wires is required between the Combiner Box and the PV controller location. This can result in a considerable savings in the cost of wire since fewer wires will have to be installed.