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 and installers are confronted with the challenge of achieving maximum availability and performance from 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 when individual strings fail.

Your advantages

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

Collection and distribution

String combiner box in the field  

Pre-assembled and tested string combiner boxes

Quick installation and startup and high system availability: using pre-assembled SCBs, you can ensure operator satisfaction.

Using optimally coordinated components and communication interfaces allows SCBs to be connected to a higher-level park management system quickly and easily.

Connection and protection

Hybrid terminal block  

Reduced wiring effort, thanks to special terminal blocks

An extensive product portfolio of a wide variety 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 arresters and surge protective devices from Phoenix Contact. The protective devices fulfill the EN 50539-11 and UL 1449 3rd ed 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 meters can be used to record and display characteristic data directly in the control cabinet.

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 also 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 reliable monitoring of photovoltaic systems


P.O.B. 1799 Industrial Park Hasharon
Quadima 60920


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