{"id":10817,"date":"2026-08-26T10:45:27","date_gmt":"2026-08-26T08:45:27","guid":{"rendered":"https:\/\/q3-energie.de\/pv-combiner-box-for-huawei-330ktl-28-strings-firefighter-switch-q3\/"},"modified":"2026-08-28T17:26:16","modified_gmt":"2026-08-28T15:26:16","slug":"pv-combiner-box-huawei-330ktl-28-strings-firefighter-switch","status":"publish","type":"post","link":"https:\/\/q3-energie.de\/en\/pv-combiner-box-huawei-330ktl-28-strings-firefighter-switch\/","title":{"rendered":"PV Combiner Box for Huawei 330KTL: 28 Strings + Firefighter Switch | Q3"},"content":{"rendered":"\n
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PV combiner box for Huawei 330KTL: 28 strings and firefighter switch in one enclosure<\/h2>\n<\/div>\n<\/div>\n<\/div><\/div>\n\n\n\n
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Custom DC connection and protection solution for a utility-scale PV system in H\u00f6rselgau<\/strong><\/h2>\n\n\n\n
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This PV combiner box for Huawei 330KTL was developed to route, protect and remotely disconnect all 28 PV strings within a single enclosure<\/strong>: for a PV installation in H\u00f6rselgau, Germany, the DC architecture was designed specifically around the input configuration of the Huawei SUN2000-330KTL inverter.<\/p>\n\n\n\n

The original requirement was straightforward. In previous projects using this inverter type, two separate PV combiner or connection boxes had been required per inverter. For this project, the objective was to accommodate all 28 PV strings in a single enclosure<\/strong> wherever technically feasible.<\/p>\n\n\n\n

Q3 ENERGIE therefore developed a project-specific version based on the QFire BIG firefighter switch. The solution combines 1:1 routing of all 28 strings with string fusing, DC surge protection and remotely controlled DC disconnection. <\/p>\n\n\n\n

Five of these units were installed in H\u00f6rselgau.<\/p>\n\n\n\n

Project implementation by Kintlein & Ose GmbH & Co. KG <\/a>\u26a1\u2600\ufe0f<\/p>\n\n\n

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Huawei 330KTL<\/h4>\n\n\n\n

28 Strings<\/h4>\n\n\n\n

QFire BIG<\/h4>\n<\/div>\n\n\n\n
Project data<\/strong><\/th>Design<\/th><\/tr><\/thead>
Application<\/td>Ground-mounted PV system<\/td><\/tr>
Location<\/td>H\u00f6rselgau, Thuringia, Germany<\/td><\/tr>
Inverter<\/td>Huawei SUN2000-330KTL<\/td><\/tr>
Technology<\/td>Project-specific QFire BIG firefighter switch<\/a><\/td><\/tr>
PV strings per box<\/td>28<\/td><\/tr>
Total string circuits<\/td>140<\/td><\/tr>
MPP trackers per inverter<\/td>6<\/td><\/tr>
System voltage<\/td>Up to 1,500 V DC<\/td><\/tr>
QFire switching current<\/td>up to 20 A Isc per string<\/td><\/tr>
String routing<\/td>28 inputs \/ 28 outputs, 1:1<\/td><\/tr>
String fusing<\/td>Positive conductor, project-specific 30 A<\/td><\/tr>
Surge protection<\/td>6 \u00d7 Type 1+2 DC SPD per box, with remote signalling contact<\/td><\/tr>
Enclosure<\/td>Sheet steel, IP66<\/td><\/tr>
Special Features<\/td>QFire BIG custom configuration for 28 strings<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>\n<\/div>\n\n\n\n
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The challenge: PV combiner box for Huawei 330KTL with 28 PV inputs in one box<\/h2>\n\n\n\n

The Huawei SUN2000-330KTL features six independent MPP trackers and a total of 28 PV inputs. The inputs are distributed across the six MPP trackers in a 4\/5\/5\/4\/5\/5 configuration. <\/p>\n\n\n\n

For the DC connection system, this results in an unusually high number of individual string circuits to be routed to each inverter.<\/p>\n\n\n\n

Using two separate enclosures is technically possible, but it increases space requirements as well as installation and cabling effort. The objective in H\u00f6rselgau was therefore to develop a solution in which all 28 strings assigned to one inverter could be routed through a single enclosure<\/strong>. <\/p>\n\n\n\n

he result was not a standard product configuration, but a project-specific design for commercial, industrial and utility-scale PV applications.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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QFire BIG custom configuration for 28 PV strings in one PV combiner box for Huawei 330KTL<\/h2>\n\n\n\n

The standard QFire BIG range is designed for switch boxes with up to 24 PV strings. For this project, the system architecture was extended to provide 28 inputs and 28 outputs<\/strong>. <\/p>\n\n\n\n

Each PV string remains individually routed from the PV generator to the corresponding inverter input. The strings are not combined within the enclosure. <\/p>\n\n\n\n

This is an important distinction. Although the unit performs functions normally associated with a PV combiner or generator connection box, the 28 string circuits remain separate throughout the enclosure. This preserves the required allocation between each PV string and the inverter’s individual inputs and MPP trackers.<\/p>\n\n\n\n

At the same time, the enclosure integrates several functions of the DC infrastructure:<\/strong><\/p>\n\n\n\n