Fire Safety Switch for PV Systems – Module String Disconnection

Photovoltaic fireman's switch for automatic and manual disconnection of PV strings - fire safety switch

Short and sweet: Basic information on the QFire Switch PV fireman's switch

The QFire Switch fireman's switch disconnects all lines from the roof junction box from the PV generator when switching. This means that all DC lines in the building are de-energised. Switching takes place via the control box, which is ideally located close to the inverters or connected to another point on the AC grid.

The main advantage of the AC-coupled disconnection system is that in the event of a fire, for example, there is no need to search for or access a switch. When the AC mains is switched off, the DC lines are also automatically disconnected from the roof switch box. When the AC mains supply is restored, the system will automatically restart.

Special Features of the Q3 Fireman's Switches QFire

Q3 Fireman's Switches QFire are certified according to IEC 60947-3 and are custom designed and built in our factory in Kaufbeuren - Made in Germany. If required, we combine all components of the connection technology - surge protection, string current measurement, etc. - and integrate them into the disconnecting box. This box is also customised to the number of strings to be disconnected. If metal enclosures are required for industrial applications - no problem!


New: Cluster Technology - up to 5 different Roof Surfaces with a Single Control Box!

Up to five different roof areas can now be controlled from a single control box. In addition to 'on' and 'off', each individual cluster also signals the status of the line and, if necessary, the functionality of the surge protection.

The distance between the control box and an individual cluster can be up to 300 metres. In the event of a power failure, all clusters will go into a safe state and automatically switch on when the power is restored. In the event of a power failure, all strings of the entire system are disconnected from the PV generator by the control boxes and are thus safely de-energised.

>> read more about the cluster technology


Technical Details

Control Box

Switch Box

Switching methode
galvanic isolation
MC4 (4-6 mm², )
Number of strings
System modular extendable with 1-99 switch boxes of max. 16 strings each
CE, IEC 60947-3:2010-02
- Material
- IP Class (EN60529)
IP 66/67
- Mechanical Resilience
IK08 (+35°C/-25°C)
- Certification
EN 62208:2011:2011
- Mounting location
protected outdoor area
- Diameter L x W x D
250 x 170 x 100 mm
for 2 - 4 strings: 300 x 400 x 132 mm

for 6 - 8 strings: 400 x 400 x 132 mm

for 10 - 16 strings: 400 x 600 x 132 mm (plastic)

for 10 - 16 strings: 400 x 600 x 150 mm (metal)
- Weight
approx. 1.1 kg
approx. 11 kg (plastic) / 15 kg (metal)
- Operation Voltage
230 VAC
- Fuse
B6 line protection
- Power Consumption
approx. 40 mA at 230 VAC
< 3 W / string connected
- Rated Voltage Isolation
1,500 VDC
- System Voltage max.
1,500 VDC
- Switch Voltage max. at 15 A
1,200 VDC
Control Voltage
12 VDC
Switch Current max. per String
15 A
Surge Protection
- Category
DC T1+2
- Telecommunication Contact
- Integrated Slave
230 VAC

for cascade circuit and control lines > 30 m
- Compliance
IEC 61634-31:2018, EN 50539-111:2012+A1:2014
optical LED status message
or LAN/ethernet optional
optical LED status message
Operation Temperature
- 15°C to +60°C
0 – 99% relative humidity (no condensation)
external key switch or emergency stop, potential-free status contact



QFire Standard or BIG? Which Fireman's Switch is suitable for your system?

QFire Fireman's Switch Standard

  • Systems for switching off up to 12 strings

QFire BIG fireman's switch

  • for more than 12 strings
  • with integrated surge protection
  • for long cable runs > 25 metres


Photovoltaic Fireman's Switch: Why actually?

In most cases, the inverter is installed close to the house's power distribution system in a central location in the building. This can be switched off, as can the entire electricity in the house. What cannot be switched off is the voltage coming from the modules: Here, up to 1,000 volts direct current remain in the building. Note: from 120 V direct current, this is considered life-threatening.

This not only concerns the fire brigade in case of fire, according to which a minimum distance of up to 5 metres (depending on whether a spray or extinguishing jet is used) must be kept from live parts, but also maintenance and cleaning work, etc. Self-protection takes precedence over external protection.

Therefore, the unanimous wish is for a safe shutdown device for photovoltaic modules in order to be able to completely disconnect the building from the power supply in the event of a fire, i.e. also from the DC side.


QFire is a PV generator disconnection device for automated galvanic isolation of PV strings according to DIN EN 60947-3:2020.


The set consists of a control box and one or more switchboxes.

The QFire control box is installed centrally near the inverter or at another accessible location. The QFire switch boxes are installed near the module at the roof inlet, from where all lines coming from the roof can be switched off safely and without arcing using special high-performance relays. In this way, the entire direct current supply can be interrupted from a central point.


With the QFire fireman's switch, the power is switched off

  • manually at the control box
  • via an external EMERGENCY OFF or key switch
  • coupled via the fire alarm panel
  • AC coupled via the mains supply in the event of a mains failure
  • if the mains supply switches back on, the system automatically goes into operation again
  • by undervoltage due to cable breakage or in the event of strong fluctuations in the AC mains supply



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QFire Feuerwehrschalter Flamme

central emergency shutdown for PV systems, customised variants adapted to the respective system

QFire Feuerwehrschalter Flamme

suitable for fire alarm systems, can be connected to fire alarm control panel

QFire Feuerwehrschalter Flamme

suitable for all modules/inverters, regardless of manufacturer

QFire Feuerwehrschalter Flamme

switches on again automatically after a power failure

QFire Feuerwehrschalter Flamme

safe disconnection of the PV generator even in case of emergency

QFire Feuerwehrschalter Flamme

arc-free switching due to innovative switching technology

QFire Feuerwehrschalter Flamme

complete set; modularly expandable and easy to install

QFire Feuerwehrschalter Flamme

control box can be switched on and off by means of an external key switch

QFire Feuerwehrschalter Flamme

AC-coupled, can therefore be triggered via the mains at any time

QFire Feuerwehrschalter Flamme

status can be transmitted to a signalling point via a potential-free contact


Feuerwehrschalter für PV Anlagen – Modul String Abschaltung
Feuerwehrschalter für PV Anlagen – Modul String Abschaltung
Feuerwehrschalter für PV Anlagen – Modul String Abschaltung
Feuerwehrschalter für PV Anlagen – Modul String Abschaltung
Feuerwehrschalter für PV Anlagen – Modul String Abschaltung
Feuerwehrschalter für PV Anlagen – Modul String Abschaltung
Feuerwehrschalter für PV Anlagen – Modul String Abschaltung
Feuerwehrschalter für PV Anlagen – Modul String Abschaltung