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Modular
The HISbox combiner box can be configured precisely to the project. From the number of strings to protection technology and additional functions such as Fireman Switch or monitoring, solutions are created that match the plant layout exactly.
Safe
String fusing, load-break switches, surge protection, and additional safety modules ensure defined, reliable shutdown behavior – both during normal operation and in service or emergency situations.
Smart
Integrated DC monitoring enables continuous monitoring of currents, voltages, temperatures, and the status of protective devices, creating transparency and high O&M efficiency.
Our HISbox® Solutions
Choosing the right DC Combiner Box configuration depends on the type of plant. Ground-mounted plants call for high current ratings, commercial and industrial plants for fire protection and expandability, and rooftop systems for a compact design.
Ground-mounted PV plants: For large solar parks with up to 1500 V DC and up to 80 A per string. Multi-MPPT segmentation and high-current variants ensure efficient current routing, clear protection and transparency in large plants.
Commercial & industrial: Commercial and industrial PV plants benefit from clearly structured DC layouts, expandable protection equipment and optional monitoring. Depending on legal requirements and the fire protection concept, a Fireman Switch may be required.
Residential rooftop systems: For residential rooftop systems, the HISbox offers reliable surge protection, straightforward integration and a compact design. The unit is factory-wired and ready for immediate use.
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Request our DC combiner box solutions for your PV project now
DC combiner boxes – robust, modular DC distribution technology for photovoltaic systems
HISbox DC combiner boxes are modularly configurable combiner boxes that combine multiple PV strings, protect cables and inverters, and form the central DC distribution level of modern photovoltaic systems. They ensure clear, service-friendly plant structures and create a durable, standards-compliant DC infrastructure.
Thanks to their modular design, they can be flexibly adapted to different project sizes and technical requirements – from residential rooftop systems to Commercial & Industrial systems through to large Utility Scale solar farms.
The base configuration includes all essential protection and switching functions and forms the foundation of every version. In addition, combiner boxes can be extended with optional function modules such as monitoring, Fireman Switch, multi-MPPT segmentation, or high-current variants.
This creates a powerful, scalable solution that is fully compatible with all leading inverters for PV systems of any size.
Base configuration – the foundation of every DC combiner box
The base configuration represents the core system of every DC combiner box. It includes all necessary protection and switching elements required for safe DC string combining. It serves as the starting point for every further expansion and forms the technical basis of the entire product concept.
Components of the base configuration:
gPV string fusing to prevent reverse currents
DC surge protection Type 2+3 or Type 1+2+3
DC disconnect switch for safe, load-free disconnection
UV-resistant enclosures made of GRP or polycarbonate (IP54–IP65, IK08)
flexible connection options (cable glands, MC4, flying leads)
consistent earthing and equipotential bonding
full compatibility with all common central inverters
This equipment defines the "combiner box" as a reliable base product – regardless of which additional modules are required for a project.
Do you have questions about the configuration? We are happy to advise you.
Expandable function modules
The following modules can be freely combined with the base configuration. They extend the DC combiner box with monitoring, fire protection functions, segmentation, or high-current capability.
The monitoring module extends the DC combiner box with detailed monitoring of DC parameters. Precise measurement of currents, voltages, temperatures, and device states enables early detection of deviations. This simplifies fault diagnosis, enables data-driven maintenance, and improves long-term yield performance – particularly in C&I and Utility Scale projects.
Functions:
Hall sensor measurement per string
Arc fault detection
Insulation monitoring
Voltage and temperature monitoring
SPD and load-break switch status
LCD display
RS485 Modbus/RTU, optional LoRa / WiFi
The Fireman Switch enables defined voltage disconnection of the DC cables – automatically on loss of grid supply, temperature-controlled, or manually via emergency stop.
It fulfills key requirements of modern fire protection concepts and provides enhanced safety for building structures and emergency services.
Functions:
automatic shutdown on AC grid loss
automatic reconnection on grid return
thermal tripping possible
manual emergency stop
complete voltage disconnection
For large inverters or modular plant layouts, multiple MPPT power paths can be cleanly separated and protected within a single DC combiner box. The segmentation supports efficient maintenance processes and clear structuring of DC cable routes.
Functions:
1–8 strings per MPPT
LBS and SPD per MPPT optional
clear, maintenance-friendly segmentation
For modern high-performance modules or long strings, variants with high current-carrying capacity are available – ideal for ground-mounted plants and high-module-count arrays.
Functions:
up to 80 A per string
gPV fuse protection 22 x 58mm
optionally combinable with monitoring
DC disconnect switches create defined isolation points in the DC circuit and enable safe shutdown of individual plant segments – an important element for maintenance, replacement, and troubleshooting.
Functions:
load-free DC disconnection
clear segmentation
robust outdoor design
SPD boxes provide enhanced protection against lightning and switching overvoltages and increase operational reliability as well as the service life of modules and inverters.
Functions:
Type 2+3 or Type 1+2+3
supplementary lightning and surge protection
ideal for long cable runs and exposed locations
High-quality connectors and industrially prefabricated cable solutions enable safe installation with low contact resistance and high operational reliability.
Functions:
verified crimp quality
Plug-and-Play installation
ideal for C&I and Utility Scale
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Are you planning a PV system and looking for the right DC combiner box configuration? – We will find the optimal solution for your project.
Get in touchSafety in combiner boxes
The safety of a DC combiner box is a central factor for the stability and operational reliability of every photovoltaic system. High voltages are permanently present on the DC side, which is why all components must be designed for defined, reliable protection and shutdown behavior. HISbox combiner boxes integrate all safety-relevant functions necessary for protecting PV strings, cables, and inverters.
Through high-quality gPV fuse protection, robust load-break switches, surge protection, and high-quality enclosure technology, electrical risks are reduced, maintenance is made safer, and the service life of the system is extended.
gPV fuse protection against reverse currents
load-break switch for safe disconnection
Surge protection Type 2+3 / Type 1+2+3
Temperature monitoring
robust, UV-resistant enclosures
IP54–IP65, IK08 impact resistance
safe connection options
consistent earthing and equipotential bonding
Monitoring in combiner boxes
Reliable monitoring in the DC combiner box is essential for continuously assessing the condition of the DC system and detecting performance losses at an early stage. Particularly in C&I and Utility Scale projects, DC monitoring enables active, data-driven plant operation. By monitoring string currents, voltage, temperature, and protective devices, deviations can be identified immediately – for example caused by soiled modules, defective connectors, or aged fuses.
RS485 Modbus/RTU
optional LoRa or WiFi
integrated LCD display
String current per input
Arc fault detection
Insulation monitoring
DC bus voltage
Enclosure temperature
SPD status
Load-break switch status
You know your requirements for protection and monitoring? Request the right HISbox solution now.
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