If lightning strikes a data center, it can have serious consequences for the IT and thus the economic efficiency of the system. Because failures due to electromagnetic interference can be expensive, for example due to repairs or if data is lost - after all, data center systems are extremely sensitive to magnetic influences from inside and out. Data centers can already be influenced by radio waves emitted by mobile phone masts. Furthermore, motors emit magnetic impulses, which can noticeably disturb the power lines in a data center and thus the IT infrastructure. In addition, a faulty electrical installation can be a significant disruptive factor. The Federal Office for Information Security (BSI) also stipulates that data centers must be planned and built in compliance with EMC. For this reason, electromagnetic compatibility (EMC) must always be ensured during construction or operation, so that the components are permanently available by excluding electromagnetic interference. Official use of the system - for example by the police or the state administration - must also be absolutely tap-proof. To ensure that the operator is on the safe side and to avoid costly failures, it is worth checking the IT and the entire data center for EMC.

Damage caused by electromagnetic influences can have various causes. The main source is usually lightning that strikes the data center or the immediate vicinity. The impact is transmitted through the power cables. The can result in malfunctions or defective systems, which lead to expensive interruptions and repairs.

In addition, dangers for a data center can also come directly from the neighborhood. If, for example, motors are used to drive machines in the neighboring building, these also emit electromagnetic interference pulses. Furthermore, transmission masts can be nearby, high-voltage lines can run above the data center or cable routes can extend below the system. "All of these sources harbor risks for a data center," says qualified engineer Martin Vogt, CTO at the Cologne-based consulting firm High Knowledge, which specializes in sustainable planning, project management and maintenance of data centers and data center infrastructure with climate neutrality as the goal. “There can be impairments or even a complex failure. Lightning creates an electronic impulse that can cause major damage.” That is why data center operations require a well thought-out concept that ensures electromagnetic compatibility (EMC).

It Depends on the Right ZEP

A faulty electrical installation is often the reason why lightning and other sources of electromagnetic interference can have far-reaching, negative consequences for a data center. A large number of cables and lines are laid in the data center and high currents flow through cables and busbars. As a rule, only one central earthing point (CEP) is necessary in the building entry, as otherwise there would be too many susceptible compensating currents, which would quickly become overloaded in the event of an external influence, such as a lightning strike. In addition, neutral conductors can be incorrectly dimensioned and not properly shielded. However, EMC can be achieved simply by correctly arranging and dimensioning the cables. Because then the system is set up so far inside that cables cannot overload. "You can always influence the internal forces on the EMC with a well thought-out electrical installation," emphasizes Vogt. “Everything that comes from outside, such as lightning strikes or radio masts, is not in the direct sphere of control. That’s why protective mechanisms must also take effect for this.”

This primarily includes the professional implementation of the ZEP in accordance with VDE 0100-444. "The ZEP is usually set incorrectly out of ignorance," says Vogt. “Often it is realized several times or not at all. This can result in several compensating currents or stray currents, which damage the entire IT and can result in serious disruptions.” Transformers, for example, are equipped with a ZEP at the factory. In many cases, this is not even considered and thus several grounding points are created in the data center. This is because the only ZEP should generally be installed in the switchgear. This component is installed in front of the actual data center and connected to the equipotential bonding and the earthing system.

The Targeted Analysis

On the way to a successful EMC concept for data centers, there is an exact analysis of the possible sources of interference in the data center at the beginning. In addition to the correct project planning of the ZEP, this also includes the exact screening of all lines within the system. The potential dangers of electromagnetic radiation from the neighborhood can also be examined in detail with special measuring devices. It is determined in detail what effects it could have on the operation of the data center, so that an EMC concept is created that the BSI stipulates according to DIN 62305. Part 3 of the standard provides classic lightning protection, which primarily provides for the protection of people. Part 4 is mainly about the EMC of the systems. The data center is divided into four zones: from "0" for outside to "4" for inside. The sensitive and fault-prone IT is located in the last zone.

"In order for EMC to be implemented consistently, various aspects should be taken into account in order to avoid errors," explains Vogt. “Of course, this includes the consistent implementation of the interference protection and lightning protection concept. Above all, it is important that a precise basic analysis is carried out at the beginning.” Furthermore, it should always be ensured that low currents run through the earthing system and that the laid neutral conductors are treated in the same way as phase conductors, since large currents can also occur here. A special measurement technique can be used for this, which ultimately helps to ensure that equalizing currents do not disrupt or even damage the highly sensitive IT systems.

A Check for Increased Security

To be on the safe side, it is worth carrying out an extensive check of the electromagnetic compatibility of the IT or the entire data center, such as that carried out by High Knowledge. The first step is a precise analysis. "Here a deep look is taken into the system in order to analyze and consistently measure which currents are flowing where and how strong," explains Vogt. After the analysis, as part of the DC EMC check, customers receive specific instructions with a to-do list in order to eliminate errors in the system as quickly as possible.

If EMC is successfully implemented in a data center, this has clear benefits for its operator. This guarantees a high level of availability, since there can be no failures due to errors in the electrical system, which in turn increases the efficiency of the data center. In addition, the data center operator can be certain that their own data center is operated in accordance with the BSI.


Successful electromagnetic compatibility is essential for trouble-free operation of a data center. Because if the sensitive IT fails after a lightning strike, for example, or if it has to be completely replaced, this has major financial consequences for the operator. Often the fault lies in the faulty electrical installation. In many cases, the implementation of the central grounding point, for example, is not implemented correctly. With a conscientious assessment of the EMC - such as the DC EMC check from the Cologne consulting firm High Knowledge - the IT can be better protected and failures avoided. After the analysis of the current status, the operators receive comprehensive instructions on how to design their system in compliance with the standards and in a fail-safe manner.