Amendment to VDE-AR standards 4105 and 4110
For a faster expansion of photovoltaics
The expansion of photovoltaic systems in Germany is progressing too slowly.
The German government’s goal of increasing the output of installed PV systems from the current 70 gigawatts to 215 gigawatts by 2030 is only possible if company and commercial roofs are used in addition to private roofs.
In order to achieve this goal, the German Solar Industry Association, the Federal Ministry of Economics, the Federal Network Agency and the Grid Technology/Grid Operation Forum of the Association for Electrical, Electronic & Information Technologies (VDE) have decided that the existing regulations must be amended.
The amendments entered into force on May 15, 2024.

The changes are intended to simplify the grid connection of PV systems in the power class between 135 kW and 500 kW and ensure lower costs.
At the same time, the amendment to the VDE-AR standards also affects the requirements as to when an EZA controller must be installed.
What do you need an EZA controller for?
EZA stands for generation system, such as photovoltaic systems or combined heat and power plants.
With an EZA controller, it is possible to regulate the feed-in of electricity from renewable energies and thus guarantee grid stability and increase the efficiency of a system.
The term EZA controller originates from the technical application guidelines (TAR), also known as VDE standards.
In accordance with the current grid connection regulations, the guidelines define the connection of systems to the low, medium, high and extra-high voltage grid and their operation.
From a feed-in power of 135 kW, system operators are required to present a system certificate.
This can be achieved by installing a certified EZA controller be installed.
You can find out exactly how an EZA controller works in our blog post "How the EZA controller works".
The innovations at a glance
1. what is changing in VDE-AR-N 4105
In future, PV systems with an output of up to 500 kW (AC) and a maximum agreed feed-in power of 270 kW will fall under VDE-AR-N 4105.
Another new feature is that system certificate B and a declaration of conformity are no longer required.
This eliminates the need for complex requirements.
In addition, it is no longer relevant whether the PV systems are connected to low or medium voltage.
However, they must have higher-level decoupling protection.
Ultimately, this gives self-consumption systems the same status as full feed-in systems and an EZA controller is no longer required.
Systems up to 135 kW
These PV systems fall under VDE-AR-N 4105 without restriction.
Systems with 135 kW to 270 kW
In addition to VDE-AR-N 4105, systems with a connected load of 135 kW to 270 kW (AC) must also deactivate stand-alone grid detection and increase the frequency cut-off threshold to 52.5 Hz.
VDE-AR-N 4110 will no longer apply to these systems in future.
Systems with 270 kW to 500 kW
For PV systems with an output of 270 kW to 500 kW (AC) and a feed-in power of 270 kW, the following conditions must be met in addition to VDE-AR-N 4105:
- Deactivation of the islanding detection and increase of the frequency cut-off to 52.5 Hz.
- a higher-level decoupling protection (üEKS) and
- monitoring the feed-in power PAV,E in accordance with VDE-AR-N 4105
2 What are the changes for VD-AR-N 4110?
For PV systems with an output of 500 kW to 950 kW (AC) and a feed-in power of more than 270 kW, the previous medium-voltage directive VDE-AR-N 4110 still applies and an EZA controller must be installed.
There are no changes to this directive, which means that PV systems of this size will continue to require a system certificate B and a declaration of conformity in accordance with the Electrotechnical Properties Verification Ordinance (NELEV).
There are also unit certificates that must be stored by manufacturers in an EZE database so that the systems can be operated.
EZE stands for generation unit and is the unit of the entire electrical machine, also referred to as a series or product.
Database for unit certificates
In addition to the changes to the VDE-AR-N 4105 and 4110 standards, it was decided that a database for unit certificates for grid-relevant components such as inverters, protection devices, battery storage, combined heat and power plants or cogeneration will be introduced by NELEV.
In future, the EZE database will be operated by the Fördergesellschaft Windenergie und andere Dezentrale Energien (FGW).
With the introduction of the database, manufacturers of components subject to certification will in future be obliged to store the unit and component certificates in the database.
This step registers the certificates.
If a component has to be recertified due to changes, the updated version must also be reported to the database.
As a general rule, PV systems may only be operated if the components used are certified accordingly.
Otherwise, the system may not be put into operation.
What initially sounds like extra work ultimately helps to simplify the installation of PV systems and at the same time ensures safe grid operation even without the system certificate B.
Conclusion: Simple and fast connection of PV systems
With the adaptation of VDE-AR standards 4105 and 4110, a first step has been taken towards a faster expansion of expansion of PV systems on the roofs of companies and municipal buildings buildings.
The simplifications will enable a simpler, faster and more cost-effective connection to the electricity grid, particularly for PV systems with an output of up to 500 kW.
They will then no longer fall under the VDE-AR-N 4110 application rule, but under VDE-AR-N 4105 and the obligation to install an EZA controller will no longer apply.
The simplifications came into force on May 15, 2024.