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What is Solar Combiner Box – The Complete Guide

Solar Combiner Box

Before investing in your next solar combiner box, read this guide. It explores all fundamental aspects about PV combiner boxes.

Let’s dive right in.

What is a Solar Panel Combiner Box?

Solar panel combiner is an enclosure that brings different outputs of solar panels into a single output.  It is important to note:

  • Solar panel output are combiner box input
  • Combiner box output is the sum solar panel input

You will find these accessories in the solar PV systems.

Occasionally, they can be used in smaller systems to simplify troubleshooting, wiring, and monitoring of the system.

Advantages of Solar PV Combiner Boxes

Insider Solar Combiner Box

Insider Solar Combiner Box

Combiners for solar PV systems provide many benefits over standalone solar PV systems, including the following;

· Easy Installation

Anyone can install solar combiners since it is quite simple. The combiners are very strong which eliminates the need of replacing them.

· Reduced Downtime

Solar PV array combiners maintain the electrical wires in an orderly way to reduce power losses in the PV system. You can isolate them from the system very easily when repairs are needed. After the maintenance is done, it is also simple to reattach them.

· Lightning and Power Surge Protection

PV systems are prone to many dangers such are lighting and power surges. They also filter the primary circuit voltage, regulate system current and protect the solar equipment from exposure to up to 1000v dc voltage from lighting

· Affordability

In comparison to other PV panel conventional connection methods, solar array combiners reduce the number of wires needed substantively. The reduction of wires needed in the system saves on the cost of installation of the PV panel system.

· Multiple Ways Panel Connection Box for Improved System Efficiency

They bring many configurations together. This has improved the efficiency of the PV systems. The boxes are more of a plug-and-play connection between photovoltaic modules. The cables are semi-flexible and easy to mount since they only require crimping or direct connection to

· Straightforward Interface

The design of the PV combiner boxes incorporates logical, consistent, and organized elements. Anyone with little familiarity with the PV system can accurately interpret the system.

Parts of Solar Combiner Box

The following parts constitute parts of a PV array combiner;

Parts of Solar Combiner Box

Parts of Solar Combiner Box

Circuit breaker

In case of faults, they terminate or isolate the circuit.

In combiner boxes, the circuit breakers are single-pole. This means that a single incoming wire can be used on only one set of contacts. They can be manually or automatically operated.

· Fuse

In case there is short circuits or there are instances of over current, they protect the entire circuit.

The tiny wire will burn through when the rated current is exceeded. This in turn disconnects the circuit from the power supply. The fuses can only be manually removed from the PV circuit and replaced when required.

· Busbar

It is a special conductor which provide many connection points. As a result, you can:

  • Integrate other connections from the solar PV systems
  • Attain the desired connection
  • May act as termination point for come connections

· Rapid Shutdown Device

For safety, the systems will de-energize solar panels faster. It allows for safe and fast control of voltage or current.

· DC Disconnects

It stops electrical slow in solar PV system.  They interrupt direct current flow in the PV module.

· DC Surge Protector

In case the solar PV systems experience overvoltage, the surge protector will ensure the entire system’s safety. Usually, this is an essential component when there is lightening.

DC surge protection device is installed to guard the PV system in case of an over-voltage.

Solar Combiner Design Considerations

There are many variables that determine the design and configuration of solar panel combiner box. Usually, they determine the dimensions in the solar combiner design diagram.

Let’s look at the critical aspects:

PV Combiner Box

PV Combiner Box

Enclosure Component Material

The PV systems combiner boxes are made from polycarbonate, stainless steel, galvanized steel or aluminum.

The material should be:

  • Durable
  • Resistant to rust
  • Withstand harsh weather conditions
  • Bes easy to fabricate and form
  • Allow unlimited finishes

Safety Standards and Quality Rating

Safety is a vital components in solar combiner box design. It should protect solar cables or connections from bad weather conditions.

Depending on where you intend to install the combiner box, it should comply with:

  • IP rating
  • NEMA rating
  • UL requirement
  • CE specifications
  • RoHS

Of course, these standards may vary depending on the solar panel installation area.

Number of Solar Panels

How to size solar combiner box starts by estimating the number of cable or solar panels. It will dictate the solar combiner box components.

These will include the number or input and bus bar size.

Therefore, it will dictate the PV systems combiner box size.

Don’t squeeze components within the box. The installation should be such that it allows for free air flow. It will enhance the cooling process.

Voltage and Current Capacity

You must know the expected voltage in your PV systems. It is an important design parameter.

Temperature Resistance

Again, temperature forms an integral environmental variable you must consider in solar combiner box design.

Customization Options

We provide a wide range of unique features that address all typical inverter concerns, from logo to components, to enhance rooftop fire prevention in residential and commercial applications. Three MPPT types and various numbers of DC inputs and outputs are present in each of our combiner boxes.

Easy to Install

A good combiner box should guarantee convenient installation mechanism. Whether it is free standing, wall mount or any other desired installation option.


The ability to adapt a combiner box to the prevailing PV systems installation requirements is very critical. However, the design will still focus on offering better protection.

How 4 String Solar Combiner Boxes Compare to 2 String Solar Comber Box

In photovoltaic system, you may encounter the terms:

  • 2 string solar combiner box
  • 12 string solar combiner box or,
  • 24 string solar combiner box

In solar systems, the word string refers to a group solar panels wired in series. Of course the aim here is to produce a specific voltage.

So, whether you talk of 4, 2 or 24 string solar combiner box – it simply refers to the group of solar panels.

Therefore, in a 4 string solar combine box, we will have both positive and negative cables. The cables come from the 4 strings of the solar panels.

In short, the difference here is in the number of solar panels in the PV system.

How Solar Combiner Box Works

Connecting Combiner Box

Connecting Combiner Box

The output string of various solar arrays is integrated into a single source by the solar panel combiner box. Each string is linked to a fuse terminal.

From each fuse output, there will be a connection to the inverter system.

In most cases, the box is usually consolidated with the extra feature when it is installed in the solar panel systems. Depending on your design, you may include other accessories such as:

  • Remote rapid shut down system
  • Disconnecting switches
  • Monitoring devices, just to mention a few.

 Recommended Solar Panel Combiner Box Standards

Although these standards may vary, let’s look at some acceptable options:

· IEC61646

Most of the aspects of this standard are similar to the IEC 61215 standard for crystalline modules. It is responsible for the protection of the PV combiners against the degradation of PV components resulting from exposure to irradiation and high temperatures.

· IEC 61730 / EN 61730

This standard covers the overall design characteristics and construction requirements for PV modules concerning safety.

· IEC 60364-4-41

IEC 60364-4-41 protects PV systems for low voltage electrical installation shocks. It ensures that all PV electrical components are insulated to ensure personnel safety and that of the PV module.

· IEC 62108

High concentrations of sunlight may cause stresses within the PV components. This standard specifies the design procedures and the solar irradiance concentrators to use in PV equipment to ensure the durability of the PV module in the environment it will be used.

· IEC 61701

The IEC 61701 certification specializes in solar PV modules to be used in highly corrosive environments like the sea. The IEC standard is responsible for ensuring the PV module is shielded from corrosion caused by the availability of salt mist in the PV system environment.

Application of Solar Panel Combiner Boxes

Solar panel PV combiner boxes are used in various sectors;

  • Homes
  • Solar pumping systems
  • Solar panel farms
  • Industries and businesses


Solar panel combiners have a range of usefulness to a majority of applications. They are easy to install, straightforward and compact, safe, and have an enhanced efficiency to the solar PV system. They are also easy to maintain, readily available in the market across the globe, and quite affordable.

For all your solar combiner boxes from China, contact us now.

More Resources:

What is a Junction Box – Source: KMDFAB

Electrical Enclosure – Source: KDMSTEEL

Solar Combiner – Source: MOSCOW

Solar Panel Combiner Box – Source: MOG

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