String combiner

String combiner

For optimum performance

With solutions for the string combiner you can achieve maximum availability and yields from your photovoltaic systems.

Back to Ground-mounted systems


Planners und installers have the challenge of achieving maximum availability and performance of photovoltaic systems. The important factors here are collecting and distributing string currents, protecting the individual modules against damage from lightning and surge voltages, and monitoring the performance of the system.

String combiner boxes (SCBs) from Phoenix Contact meet these requirements in a space-saving housing. Our photovoltaic string current monitoring system enables you to respond immediately to malfunctions and power losses, even in the event of the failure of individual strings.

Your advantages

  • Application-oriented analysis for optimum positioning of the surge protection
  • Reduced costs and wiring effort
  • A separate power supply unit in the field is not necessary
  • Space-saving installation, thanks to the compact design
  • Voltage measurement up to 1500 V DC

Connection and protection

Hybrid terminal block  

Reduced wiring effort thanks to special terminal blocks

An extensive product portfolio featuring a wide variety of terminal blocks provides the right solution for any application. Fuse terminal blocks are ideal for protecting individual strings against reverse currents.

Diode terminal blocks are specifically designed for the use of photovoltaic thin film, while the hybrid terminal block merges up to four strings without additional cabling effort.

Protect against surge voltages

Surge protection for photovoltaic systems  

Reliable surge protection for photovoltaic systems

Due to their size and exposed location, ground-mounted photovoltaic systems are particularly at risk from
lightning currents and surge voltages.

Take preventive action and significantly increase the availability of your system with lightning current and surge protective devices from Phoenix Contact. The protective devices meet the EN 50539-11 and UL 1449 3rd edition standards for surge protection in photovoltaic installations and are KEMA-certified.

Monitoring string currents and voltages

Current measuring modules  

Monitoring of photovoltaic systems at string level

Using Hall sensors, the current measuring module determines the characteristic data of your photovoltaic systems on a contact-free basis and forwards it to the communication module. 4- and 8-channel versions are available.

With the voltage measuring module, you can measure DC voltages up to 1500 V. The module is suitable for measurements in both grounded and isolated photovoltaic systems.

Power supply

DC/DC converters  

Compact DC/DC converters with basic functionality for photovoltaics

The new DC/DC converter with basic functionality for photovoltaics allows you to supply your string combiner boxes directly from the ground-mounted system.

As a result, you save on installation costs and increase system efficiency. Due to the compact design and the high efficiency, the DC/DC converter can also be used in small control boxes.

Converting and monitoring currents from bus cables

Current transducers  

Monitoring DC bus cables in photovoltaic systems

DC bus cables of up to 600 A are monitored with the universal AC/DC current transducers. This means that the conductor that is to be monitored does not have to be interrupted.

The current transformers make it possible to convert alternating currents for different transmission ratios. Downstream energy measuring devices can be used to record and display characteristic data directly in the control cabinet.

Park management

Data from park devices can be output via serial RS-485 interfaces and transmitted wirelessly to the central park management system. Since our Radioline system allows for the set-up of mesh networks, devices can communicate with each other via repeater/slave stations.

Monitoring photovoltaic strings

The measuring module can be used to measure up to eight direct currents and one DC voltage value at the same time. The complete system enables you to operate eight measuring modules on one communication module.

The 2-conductor communication cable is used to supply the measuring modules with power. An additional power supply is not necessary. The universal current measuring transducer enables measurements of AC/DC currents on bus cables.

Monitoring photovoltaic strings

From string to bus cables, Phoenix Contact ensures the reliable monitoring of photovoltaic systems


C6 The Exchange
Calmount Park
Dublin 12
D12 XE18


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