Fireman’s Switch QFire

QFire Generator Disconnection Fireman's Switch Key Switch

Fire safety switch for PV systems

In the Q Fire Switch fireman's switch, all lines from the isolation box on the roof are galvanically separated from the PV generator in the event of a switch. Thus all DC lines in the building are voltage-free.
Switching is carried out via the control box, which is ideally located near the inverters or connected to another point on the AC grid.


  • safe switching off of the PV generator even in an emergency
  • AC coupled, can therefore be triggered at any time via the mains
  • arc-free switching through modern switching technology
  • The Q-Fire control box can be switched on and off using an external key switch.
  • complete set; modularly expandable and easy to install
  • switches back on automatically after a power failure

The AC coupled switch-off has the main advantage that in case of fire, for example, it is not necessary to look for a switch or that it is no longer accessible. By disconnecting the AC mains, the DC lines from the switch box on the roof are also automatically disconnected. If the AC mains is switched on again, the system also automatically restarts.

2-String Shutdown

4-String Shutdown

8-String Shutdown

12-String Shutdown

Number of strings
- extension arbitrary cascadable
- up to max. 12 Strings per set
- up to 16 strings per BIG Box
IP class
Mounting location
protected outdoor area
Max. system voltage per string
1.200 VDC (other ranges on request)
Max. string current (Isc)
11 A (other ranges on request)
Temperature range operation
-15 to +60° C
Connection AC side
Wieland connector
DC Connection
MC4 4,0 - 6,0 mm²
Switching method
galvanic isolation
Control voltage
12 VDC
Status LED
External switch
potential-free contact
Housing dimensions (L x W x H, without plug)
175 x 175 x 75 mm
Weight of control box | switch box
1.055 g | 989 g
CE, DIN EN 60947-3:2010-02

The basic version of the system can switch off 2 or 4 strings and can be expanded in a modular way almost at will! One control box supplies up to 3 switch boxes, with each of which 4 strings can be switched off. If this is not enough, a slave control box is added, which in turn can switch off up to 3x 4 strings. And if this is still not enough, ... You can imagine it!

Customised Variants Fireman's Switch: Big Box with Surge Protection

We would be pleased to design our fireman's switch QFire for you as a customer-specific solution, for example as a Big Box for disconnecting up to 16 PV strings, also including surge protection. Just let us know what you need - sometimes "off-the-shelf" solutions are simply not the right thing!

QFire BIG fireman's switch with overvoltage protection Wiring diagram

In this case, we equipped an industrial building with a 1 MW rooftop system (128 strings) with generator disconnection and surge protection. The QFire BIG switch boxes also contain a T2 surge arrester. A T1+T2 combination arrester would also be possible here. Each of these BIG switch boxes switches up to 16 strings.

QFire BIG fireman's switch with overvoltage protection
QFire BIG fireman's switch with overvoltage protection set