The Essence of a Solar Combiner Box

In photovoltaic (PV) power generation systems, a solar combiner box—also known as a convergence or confluence box—plays a crucial role. Its primary function is to connect and secure multiple solar panels, allowing them to work together effectively and safely. A combiner box merges the output from several solar panels into one output, which is then connected to an inverter for power conversion into alternating current (AC).


Two Main Categories of Confluence Boxes

Confluence boxes are generally divided into two main types: string combiner boxes and array combiner boxes.

1. String Combiner Boxes: These boxes deal with the output from multiple PV strings, which are groups of solar panels connected in series. They usually include fuses or circuit breakers for each string to provide overcurrent protection and ensure the safety of the entire system.

2. Array Combiner Boxes: These boxes are used when several PV arrays (collections of PV strings) are connected in parallel. They combine the output from all arrays into a single output, similarly to string combiner boxes. Array combiner boxes also incorporate overcurrent protection for each array.


Combiner Box Application Scenarios

Combiner boxes find their application in various solar PV system configurations, such as residential, commercial, and utility-scale projects. They are essential in systems with multiple solar panels, as they help maintain stable voltage and current levels, enhance system efficiency, and ensure the safety of the entire system.


Connecting a Combiner Box to a PV Panel: A Step-by-Step Guide

To attach a combiner box to PV panels, follow these steps:

1. Determine the required number of strings and arrays based on the system's size and configuration.
2. Connect the positive and negative wires from each PV string or array to the respective input terminals of the combiner box.
3. Verify that each string or array has appropriate overcurrent protection (fuses or circuit breakers) installed within the combiner box.
4. Connect the combiner box's output to the input terminals of the inverter.


Combiner box wiring


Combiner Boxes vs. Junction Boxes: Identifying the Differences

While both combiner boxes and junction boxes serve crucial roles in a solar PV system, they have distinct functions. A combiner box is responsible for connecting and safeguarding multiple solar panels, whereas a junction box is typically found on the back of an individual solar panel. The junction box contains the electrical connections and diodes required for the panel's proper functioning. In contrast, a combiner box consolidates the output from several panels and protects the system from overcurrents and other electrical issues.
July 13, 2023