Custom Combiner Box (GCB)
for PV systems up to 1,500 V DC

Yes. Depending on the system concept, a PV generator junction box can be combined with a DC-side shutdown solution such as the QFire firefighter switch. The junction box handles string bundling, surge protection and, if required, fusing, while QFire provides generator-side galvanic isolation of the PV strings.

The need for string fuses depends on the number of strings connected in parallel and the permissible reverse-current values of the PV modules used. The decisive factors are the module manufacturer specifications and the maximum possible reverse currents within the generator field. When designing, both the short-circuit current (Isc) and the number of parallel generator strings are taken into account.

Blocking diodes are used when reverse currents between generator fields need to be prevented. In modern photovoltaic systems, string fuses are often used. Whether diodes are useful or required depends on the specific system architecture and the specifications of the inverter or system manufacturer.

The number of surge protective devices is generally based on the number of MPP trackers and the selected protection concept of the system. In many applications, a separate SPD is provided per MPP tracker. The final design is project-specific, based on the system structure and cable routing.

Yes. Generator connection boxes are designed on a project-specific basis and can take different string counts per MPPT into account. This also makes it possible to combine complex generator fields with different roof areas, orientations or module layouts within one system.

For a fast and reliable design, the string plan, inverter type, number of MPPT, string allocation per MPPT and module data are particularly helpful. In addition, information on short-circuit current (Isc), the desired protection concept and the connection technology is required.

For a fast and reliable design, the string plan, inverter type, number of MPPT, string allocation per MPPT and module data are particularly helpful. In addition, information on short-circuit current (Isc), the desired protection concept and the connection technology is required.

This depends less on the number of strings than on the overall component setup. Additional fuses, surge protective devices, isolator switches or monitoring components increase the space requirement. For larger generator connection boxes, sheet steel enclosures are therefore often used.

For very large systems with high string counts, advanced monitoring or the requirement for string-level fault detection, an intelligent DC combiner solution can make more sense than a classic generator connection box. For such applications, we offer the Super Multi Box (SMB), a smart DC combiner box with integrated string monitoring, communication interfaces and project-specific protection and switching functions.