DC Combiner Box 6 Strings 1000V IP65 Photovoltaic QDC-06/06
DC field box for 6 independent strings (6 IN / 6 OUT) up to 1000 V, to be installed between the photovoltaic modules and the inverter. It integrates disconnectable fuse holders, 1000 V DC switch-disconnectors and surge protection devices for each string, with separate input and output terminal blocks.
IP65 enclosure for 36 modules with component labeling on plastic-coated rails.
The QDC-06/06-1000V PV array combiner box protects and isolates the direct current side of a photovoltaic system with 6 independent strings up to 1000 V DC. It is installed between the module array and the inverter and performs three distinct functions: isolating each string for maintenance, protecting it against reverse overcurrents, and discharging atmospheric overvoltages to earth before they reach the MPPTs.
Why the PV array combiner box is not optional
The CEI 82-25 and CEI EN IEC 62548 standards require the photovoltaic generator to be safely isolatable and protected against overvoltages. The critical point is that the DC side has no zero crossing: improvised isolation with an unsuitable device generates an arc that does not extinguish by itself. The switch-disconnectors installed in this box are specified for 1000 V direct current and can be operated under load.
The DC surge protection device must also be installed within approximately 10 metres of cable from the device to be protected: a combiner box positioned near the inverter protects the inverter, while one positioned on the roof protects the strings. On large systems, both are required.
QDC-06/06-1000V technical specifications
| Configuration | 6 strings IN / 6 strings OUT (independent) |
| Rated voltage | 1000 V DC |
| String protection | 6 isolatable fuse holders with 32 A 1000 V DC fuses |
| Isolation | 6 switch-disconnectors 1000 V DC |
| Overvoltages | 6 SPD surge protection devices 1000 V DC |
| Connections | Separate input and output terminal blocks |
| Enclosure | IP65 box with 36 DIN modules |
| Identification | Component labels on plastic-coated rails |
| Weight | 10 kg |
String fuses: when they are really needed
On this box, the strings remain independent: six inputs, six outputs, no internal parallel connection. In this type of configuration, the reverse current that can flow through a faulty string is limited, and the fuse mainly serves as back-up protection and removable isolation. Fuses instead become essential when multiple strings are connected in parallel downstream, or when the module manufacturer specifies string protection (the maximum series fuse rating value on the module datasheet).
Honest technical note: the product code indicates 16 A, while the declared configuration includes 32 A 1000 V DC fuses. Before ordering, it is advisable to confirm the actual rating required by your array, which depends on the Isc of the modules and the number of strings connected in parallel downstream.
What is included in the supply
- Wired box ready for installation
- Components identified with labels on plastic-coated rails
- Prearranged input and output terminal blocks
- Supporting documentation for the system declaration of conformity
Frequently asked questions
Is the PV array combiner box legally mandatory?
There is no explicit obligation in a single article, but CEI 82-25 and CEI EN IEC 62548 require the photovoltaic generator to be isolatable and protected against overcurrents and overvoltages. In practice, without a PV array combiner box, the system declaration of conformity is not sustainable.
Can I use it with an inverter that has fewer than 6 MPPTs?
Yes. The six outputs can be connected to different MPPTs, or connected in parallel downstream of the box to feed into a smaller number of inverter inputs. In the latter case, the string fuse becomes active protection and not just back-up protection.
Where should it be installed: near the modules or near the inverter?
The surge protection device provides effective protection within approximately 10 metres of cable. If the box is near the inverter, it protects the inverter; if it is on the roof, it protects the module array. On systems with long DC cable runs, the correct solution includes protection at both ends.
Is the IP65 rating sufficient for outdoor installation?
IP65 guarantees protection against dust and water jets and is suitable for outdoor use. However, direct exposure to sunlight throughout the day should be avoided: the internal temperature reduces the service life of the surge protection devices. Positioning in the shade or under a canopy is always preferable.
Do the surge protection devices need to be checked over time?
Yes. SPD cartridges have an indicator window that changes from green to red when the cartridge is depleted, typically after discharging one or more overvoltages. It must be checked during every routine maintenance operation and replaced if necessary; otherwise, the system remains unprotected.