Generator connection box for large systems Stringbox BIG

Connection technology PV generator junction box GAK Stringbox BIG Large systems Megawatt range



Stringbox BIG



  • Individually interchangeable
  • Plastic or steel housing possible
  • Everything available from standard to high-end


Areas of application
Large systems in the megawatt range, ground-mounted systems and large rooftop systems (e.g. factory buildings).

Basic structure of Stringbox BIG

The Stringbox BIG is a generator connection box for large systems. There are 5 standard variants with 8, 12, 16, 20 and 24 inputs. All the usual modules for large systems such as DC disconnectors, overvoltage protection, PV fuses, current sensors and string monitoring can be integrated here. The Stringbox BIG is usually planned and assembled to customer specifications. Nothing is left to be desired here. We can even monitor wirelessly - via LoRa WAN! Simply save yourself the trouble of wiring!

String boxes and generator connection box from Q3

Our generator junction box ensure a high level of safety right from the installation stage and guarantee clean and clear wiring (wiring) of PV modules on the roof or in the open field. Several strings often have to be connected in parallel in order to transport suitable power to the inverter at reasonable system voltages. The individual strings are connected directly to the modules in the string box and connected to the inverter input with just two cables (plus and minus). Each generator connection box contains a pressure equalization element as standard for effective protection against condensation.

Generator connection box Stringbox BIG with 8-16 strings remotely triggered DC disconnector Sensor fuses in positive and negative poles
Generator connection box Stringbox BIG in plastic housing, 16 strings 15 A, fuses in the positive pole. Current measurement i'checker 4, bundled strings. ÜSS T2, remote signaling contact, ÜSS 24 VDC bus, DC disconnector 315 A/1 kV
PV connection technology Generator connection box GAK Stringbox

Technische Daten Stringbox BIG


Anzahl der Strings8 bis 24
I max. pro String30 A
U max. pro String1 kV
KontaktierungM12/M16/M20/M25 (nach Wahl)
Stecker Kabelquerschnitt1 bis 25 mm²


Anzahl der Ausgänge1
I max. pro String800 A
U max. pro String1 kV
KontaktierungM40/M50/M63/M75 (nach Wahl)
Stecker Kabelquerschnitt95 bis 300 mm²


GehäuseStahlblechgehäuse, IP55, optional mit Lüfter/Heizung


DC Freischalter
Überspannungsschutz T1+T2/T2
Datenübertragung via RS485
Datenübertragung via LoRa/GSM (kabellos)

Our portfolio in the field of connection technology, string boxes, generator connection boxes (GAK)

Stringbox Simple

Extremely low profile, up to 5 inputs

Stringbox Easy

Extremely compact, up to 18 inputs

Stringbox Duo/Trio Channel with galvanically isolated circuit boards

Duo/Trio channel

Stringbox with galvanically isolated circuit boards

Stringbox Big generator connection box for large systems and parks

Stringbox BIG

Generator connection box for large systems/parks

AC sub-distribution board

Customer-specific variant with ÜSS T1+T2

Special boxes

cost-optimized - benefit-optimized

Generator connection box "large"

with overvoltage protection

Generator connection box "small"

with overvoltage protection