Photovoltaic DC Combiner Box (Also known simply as “Combiner Box”)

The Photovoltaic DC Combiner Box is a key component in a solar PV array, acting as the interface between the PV modules and the inverter. Its primary function is to aggregate multiple strings of DC power generated by PV modules and transmit the combined output to the inverter for DC-to-AC conversion. In addition to its core distribution role, the combiner box also provides circuit protection, monitoring, and safety functions, making it a crucial element for enhancing the efficiency and safety of PV systems.

Working Principle:
PV modules typically output DC power in multiple strings (each string consisting of several modules connected in series). The combiner box collects these inputs—ranging from 4–8 up to 16–32 strings—and consolidates them into 1 or 2 main output circuits connected to the inverter. This reduces the inverter’s input burden, simplifies system wiring, and lowers cable losses.

Key Protection Features:
Reverse Polarity Protection:
Prevents damage caused by incorrect polarity connections from PV strings, avoiding reverse current flow that could harm PV modules or inverters.

Overcurrent / Short-Circuit Protection:
Each PV string is equipped with DC fuses or DC circuit breakers. In the event of a short circuit or overcurrent on any string, the device quickly isolates the faulted circuit to prevent it from affecting the entire array.

Surge Protection:
Integrated DC surge protective devices (SPDs) suppress overvoltage caused by lightning strikes or grid disturbances, safeguarding downstream equipment such as inverters and monitoring units.

Rated Voltage: DC 1000V
Rated Current: 400A
Protection Class: IP65