Firefighter Switch
QFire LITE for PV Systems
Standardized DC-side string shutdown for small and medium-sized photovoltaic systems – compact, compliant with standards, and easy to integrate.
Application Area of the QFire LITE Firefighter Switch
Der QFire LITE ist ausgelegt für typische Aufdach-PV-Anlagen im Wohn- und Gewerbebereich mit überschaubarer Stringanzahl und klaren Leitungswegen.
Ideal für Anlagen mit wenigen Generatorfeldern ohne komplexe Dachaufteilung oder spätere Erweiterungsstufen.
Geeignet zur Umsetzung gängiger Vorgaben von Feuerwehr, Versicherern und Netzbetreibern bei überschaubaren Anlagenkonzepten.
Was ist der QFire LITE Feuerwehrschalter?
Der QFire LITE ist eine standardisierte Abschaltlösung zur DC-seitigen String-Abschaltung von Photovoltaik-Anlagen. Die Abschaltung erfolgt direkt in der Schaltbox und sorgt im Auslösefall für eine galvanische Trennung der PV-Strings.
Der Fokus liegt auf einfacher Integration, klar definierten Varianten und einer kosteneffizienten Umsetzung bei gleichzeitig normkonformer Ausführung.
Für wen ist der QFire LITE ausgelegt?
Functional Principle + Shutdown Logic
The QFire LITE firefighter switch galvanically and mechanically disconnects the connected PV strings in the event of triggering. Activation can occur via:
After the return of AC voltage, the system can – depending on the configuration – automatically reconnect.
Galvanic Isolation – Maximum Safety
The QFire LITE relies on complete galvanic isolation of all active conductors (+ and −). This achieves a permanent and clear de-energization of the DC lines – regardless of the state of the power grid or external control signals.
Shutdown is carried out in accordance with IEC / DIN EN 60947-3, thus fulfilling the relevant normative requirements for DC switch-disconnectors.
QFire LITE Firefighter Switch: Standardized Version
The QFire LITE firefighter switch is intentionally not modular. It is offered in clearly defined variants.
This enables quick selection, short delivery times, and simple project planning.
Difference between QFire LITE vs. QFire BIG Firefighter Switch
| QFire LITE | QFire BIG |
|---|---|
| standardized solution | modular + scalable |
| fixed variants | freely configurable |
| no cluster technology | cluster-capable |
| ideal for small / medium-sized systems | for large & complex systems |
Technical Data + Standards QFire LITE Firefighter Switch
Safety architecture of the PV system
Practical Example – QFire LITE Firefighter Switch for facade PV on high-rise buildings:
High-rise PV with string-wise shutdown per floor
Typical application areas include residential high-rises, facade PV projects, and buildings with tenant electricity or district supply concepts.
In the case of photovoltaic systems on high-rise buildings, where a separate PV string is routed along the facade for each floor and enters the building, special requirements arise for DC-side safety and shutdown logic.
In such cases, building insurers and fire departments demand a clear, reproducible shutdown solution that takes effect automatically in the event of a fire. The QFire LITE firefighter switch is ideal for this application.
Typical project requirement
■ One PV string per floor with separate building entry
■ Different string bundling at the inverter (1-, 2-, or 3-fold per MPPT)
■ High requirements for personal and operational safety
■ Central shutdown option for the fire department
■ High requirements for personal and operational safety
■ Norm-compliant design according to current DC switching and fire protection requirements
Solution with QFire LITE
A QFire LITE firefighter switch is installed on each floor directly at the entry point of the DC lines. In the event of triggering, galvanic isolation of the PV strings occurs immediately before entry into the building.
The QFire LITE units can be controlled centrally via a looped-through 230 V AC supply. If this supply is interrupted in the event of a fire – e.g., via a central firefighter emergency stop in the basement – all connected firefighter switches shut down simultaneously.
Advantages of this solution
Galvanische DC-Trennung je Etage
Maximale Sicherheit für Einsatzkräfte, unabhängig von der Anlagenstruktur.
Zentrale Auslösung, dezentrale Abschaltung
Ein einziger Auslösepunkt genügt, die Abschaltung erfolgt lokal und eindeutig.
Standardisierte, skalierbare Lösung
Ideal für Hochhäuser mit vielen identischen Abschaltpunkten.
Optional integration of surge protection and string fuses
Type 1+2 surge protection and double-pole PV fuses possible depending on the string concept.
Norm-compliant design
Certified according to IEC 60947-3, suitable for high DC voltages up to 1,500 V.
Support with planning
Send us your design; we would be happy to support you with the planning.
Project Inquiry QFire LITE Firefighter Switch
Would you like to design the QFire LITE system for a specific project, have technical details checked, or select the appropriate system configuration for your photovoltaic system?
Using the inquiry form below, we collect all relevant project data in a structured and transparent manner.
You are welcome to send wiring diagrams, string plans, or other technical documents directly. Based on this, we will check the technical framework, design the QFire LITE system to suit your project, and coordinate the components specifically.
Should any questions arise, we will contact you. Otherwise, you will receive a project-specific offer directly.
Firefighter Switch Project Inquiry
Project-related inquiry for the design of the QFire system. Selection of components and creation of an offer.
Firefighter Switch Technical Download
Data sheets, certificates, and technical documentation for QFire BIG and LITE, control boxes, switch boxes, and accessories.
Functionality & Technology QFire
Technical basics for DC-side shutdown, system structure, triggering types, galvanic isolation, and norm-compliant implementation.
FAQ on the subject of firefighter switches
Answers to frequently asked questions about application, standards, triggering concepts, mandatory requirements, and operation of firefighter switches in PV systems.