How to Install A Solar Combiner Box Properly?

Home How to Install A Solar Combiner Box Properly?

Monitoring and detaching outdoor string combiner box, a Solar Combiner Box is built for optimum performance and utmost safety. One can take advantage of the Combiner Box’s high level of system performance monitoring and superior system safety. There are three sizes of the Combiner Box, each of which can hold up to 16, 36, or 64 strings.

A solar string box is similar to an electrical junction box in that both contain multiple wires and cables and closely connect those connections through various points of entry. The solar combiner box is used, as its name implies, to connect numerous strings of photovoltaic (PV) modules to a single standard bus. The PV combiner box is then connected to the fibers. In today’s blog, we are going to talk about how to install a solar combiner box properly.

Tools And Components That Are Needed 

The solar combiner box installation can be completed with common tools. The following equipment is advised:

  1. Electrical screwdriver (tester)
  2. Box is installed
  3. Provided screws for attaching the Combiner Box to a wall
  4. Flat-head screwdriver
  5. Drilling machine and bits suitable for a wall or pole 
  6. Wire cutters
  7. Wire strippers
  8. Clump-on DC current meter
  9. Voltmeter

One might also require the following items to install the communication option:

For Ethernet:

  1. RJ45 connectors
  2. CAT5 twisted-pair Ethernet cable
  3. RJ45 crimping tool

Types of Solar Combiner Box Wiring Diagram

solar combiner box 2
Source: Beny

The majority of wiring schematics included with commercial combiner boxes are straightforward, understandable visual types. On rare occasions, though, they will also contain traditional circuit diagrams created for use by qualified installers.

For laypeople and DIY enthusiasts, pictorial schematics are by far the most user-friendly type. Circuit diagrams are often composed of line drawings that are logically organized, with the components represented by electrical circuit symbols. They will make sense if your background is in electrical engineering. A visual schematic will be much simpler to utilize if not. The mounting, electrical components, and input and output wiring locations for combiner boxes are typically shown in illustrations that go along with the wiring schematics.

Common Symbols And Terminology

solar combiner box
Source: Pinterest

Because they graphically represent a solar panel, circuit breaker, etc., pictorial wiring diagrams are relatively simple to comprehend. Schematic diagrams, which employ symbols to denote their constituent parts, might be a little challenging to comprehend. Fortunately, there are huge listings of solar and general electrical symbols available online from numerous sources. The most typical symbols and their meanings are listed below.

Note that these symbols are dictated and governed by two international electrical standards bodies. The IEC covers the remainder of the world, while the NEC only covers North America, Canada, and portions of South America. Although their respective insignia are different, they are enough alike to be instantly recognizable.

Especially in non-pictorial solar combiner box wiring diagrams, you’ll see a lot of the same symbols and terminologies. Let’s take a deeper look at the terms and symbols that you’re most likely to encounter.

Common Terms

Circuit Breaker

An electrical circuit can be manually isolated or disconnected using a switch, or it can automatically open and disconnect in the event of a short circuit or spike in current. Circuit breakers used in combiner boxes are typically single-pole devices, which means they only have one set of contacts for usage with a single incoming wire.


Circuit breakers and fuses have a similar function of cutting off the relevant circuit in the event of an overcurrent or short circuit. The key distinction between the two is that fuses are frequently not mechanical devices. They rely on a thin wire or filament that burns through or “blows” when the fuse’s rating is exceeded. This successfully isolates or disconnects the impacted circuit. Numerous fuse types can be manually removed from the circuit, isolated, and then replaced as needed.


A conductive metal rail or strip with numerous connection points is known as a busbar. This makes it possible to integrate several incoming cables into a single component. There is continuity between the incoming and outgoing parts thanks to the outgoing wire’s connection to the busbar. To combine the incoming negative or ground leads from the solar panels, busbars are most frequently employed.

Bridge Bar

The outgoing terminals of circuit breakers and fuses are connected or bridged using this metal strip, which has multiple distinct “fingers.” On the side of the circuit breaker that is opposite the incoming positive wires, they are mounted. They combine several inputs into a single output, much like a busbar.


The enclosure is the actual container in which the combiner’s parts are mounted.

Terminal Strip

Similar to a busbar, a terminal strip is typically composed of ABS composite rather than metal.

Details Diagrams Should Include

A decent combiner box wiring diagram should include a clear schematic illustration of the box and clearly designated labels for all internal parts, such as busbars and circuit breakers. The location of each incoming and outgoing wire as well as how they are linked should be clearly shown. These would consist of the cables that lead from the solar panels to the charge controller and battery bank, as well as the ground wire connection points.

There should be a list of all internal components’ scores as well. On the wiring schematic, for instance, one should clearly indicate the voltage and amperage specifications for each circuit breaker or fuse. This goes hand in hand with a precise explanation of the maximum safe input voltage and current specifications for the box.

Wiring Steps

  • On top of the solar battery bank, mount the solar charge controller. Screw one end of the positive and negative wires to the appropriate nodes on the charge controller, depending on the model.
  • Connect the other end of those cables to the relevant nodes of the battery bank using a positive-to-positive and a negative-to-negative connection once both wires have been connected to the charge controller. For further information, it is best to consult solar PV combiner wiring diagrams.
  • Connect the solar panel wire to the combiner box’s single pair of MC4 connectors.
  • Use the output connection to attach the aching wire to the blanket breaker. Use screws to secure it.
  • The positive and negative output wires should be threaded through the DC Output-designated holes. Utilizing screws, attach these output wires to the blanket breaker.
  • Connect the solar charge controller and solar combiner box/junction box by wiring them together. Make sure the wires don’t cross over one another.
  • Use a screw to fasten the DC light to the solar charge controller.
  • To check that the system works, flip on the lamp switch.


If the wiring diagram for the solar combiner box is unclear or lacking, you’ll need to find a better example, get help understanding it, or perhaps draw one up yourself. By outlining the many kinds of diagrams you can run into and how to locate, read, and comprehend them, we can assist you in accomplishing this. 

We’ve also explained the many symbols and terms that are used in wiring diagrams to represent things like fuses, circuit breakers, and solar panels, to mention a few. Contact Beny for more details.

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