Disconnection of PV Systems Fireman’s Switch – new: “Cluster” Technology!


Q3 ENERGIE GmbH & Co. KG presents "cluster" technology for central shutdown of large-scale PV systems


"Cluster" technology for central switch-off of large-scale PV systems

In the area of large rooftop systems, the disconnection of the PV generators either directly at the roof inlet or immediately afterwards is an indispensable safety feature of modern PV systems. This is the only way to ensure that in the event of a fault in the building, for example in the event of a fire, the PV lines penetrating the building can be de-energised.


The Bavarian manufacturer of energy communication technology Q3 ENERGIE GmbH & Co. KG has been offering corresponding switching technology since 2012. Here, the devices are usually planned and set up specifically for the project. Thus, in addition to the pure switching technology, the switch boxes can also already contain the overvoltage protection or lines can be combined as in a string box and provided with fuses. The switch-off itself then takes place via a control box. This can also detect a line break and display the status message of overvoltage protection modules. If required, an additional external emergency stop can be connected, as well as a potential-free contact that signals the system status at a fire alarm centre, for example.


In order to simplify the cable routing from the control box to the individual roof areas, Q3 has now developed a cluster technology. With a single control box, up to five different roof areas can now be approached and switched off. In addition to "on and off", each individual cluster also signals the line status and, if necessary, the functionality of the overvoltage 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 go into a safe state and automatically switch on when the network is restored. In the event of switching, all strings of the entire system are disconnected from the PV generator from the control boxes and are thus safely voltage-free.

System example: Switching scheme "Cluster" technology for central switching off of large-scale PV systems

The system has recently been adapted to the higher module outputs and strings with up to 1,500 volts DC at 15A string current can be switched. The Q3 system is certified according to IEC 60946 and can be individually integrated into a wide range of system types and sizes. Q3 offers regular training courses for planners and installers.


>> more about our QFire fireman's switches


Visit us at the Intersolar!


Visit us at the Intersolar!