With the rapid advance of digitalization, the rise of cloud-based applications, and the increasing use of artificial intelligence, the need for high-performance data centers is continuously increasing. This development not only brings with it new technical challenges but also places the highest demands on the security of supply and energy efficiency of these critical infrastructures.
Author: Jens Schübel
Editor: Jörg Schröper
Image: Konstantin Dem – shutterstock.com
An often underestimated yet essential component for ensuring stable and economical operation is residual current monitoring (RCM). It enables the early detection of fault currents and thus makes a key contribution to trouble-free operation and compliance with legal requirements. This type of measurement is not an optional extra, but a fundamental prerequisite for a safe, reliable power supply. In addition to residual current measurement, voltage quality measurement and operating current measurement are also part of a secure power supply.
Rising Energy Demand and Growing Requirements
The energy consumption of German data centers almost doubled between 2012 and 2022. Consumption was estimated at around 20 billion kilowatt hours (kWh) for 2024, and the trend is rising. Experts expect this to rise to up to 37 terawatt hours (TWh) by 2030. Given this development, the efficient use of energy and continuous monitoring of the power supply are becoming mandatory. In addition to measuring voltage quality and operating currents, residual current measurement is increasingly establishing itself as an indispensable measure in the energy management of modern IT infrastructures. Such measurements can help detect faults early and make operations more economical.
Residual Current Measurement: Function and Importance
To understand its importance, it's worth taking a look at the basics: Residual current measurement compares the sum of the forward and return currents in an electrical circuit. A deviation indicates that electrical energy is being undesirably discharged – for example, due to insulation faults, damaged cables, or creeping currents. Such fault currents can not only lead to corrosion of metal installations (e.g., sprinkler pipes), but in the worst case, can cause fires or system failures. RCM systems detect these deviations continuously and non-invasively. Type B+ devices must be used, especially in environments with variable-frequency drives or switching power supplies—of which many are installed in data centers. These detect both low- and high-frequency fault currents up to the direct current range, thus providing comprehensive monitoring. According to the Bitkom guideline "Operationally Reliable Data Centers," the highest availability requirements are a must in data centers. This also means that the power supply must be reliable and safe. Continuous monitoring of the electrical installation and a "clean" TN-S system play a crucial role in this. In this context, residual current measurement helps to detect faults early, before they lead to major problems or even failures.
Avoiding Automatic Shutdowns
A common mistake in practice is to equate residual current measurement with conventional residual current devices (RCDs). While both systems detect residual currents, an RCD immediately interrupts the circuit when a limit is reached, an RCM serves only as a monitoring device. An immediate shutdown – as triggered by RCDs – would be fatal in high-availability data center operations. RCM systems report anomalies in a timely manner without interrupting the power supply. This keeps the data center online while technical measures can be planned and implemented in a targeted manner.
Legal Basis and Normative Requirements
The importance of residual current measurement is also underpinned by numerous standards and regulations. These include:
- DIN VDE 0100-410: Requirements for final circuits
- DIN VDE 0100-600: Testing of new and expanded systems
- DIN VDE 0105-100/A1: Regular repeat tests
- DGUV Regulation 3: Mandatory periodic tests
- DIN EN 50600-2-2: Obligation to continuously measure residual current in new data centers
A particular advantage arises from DIN VDE 0105-100/A1 in conjunction with DGUV Regulation 3: If a circuit is continuously monitored by a residual current monitoring device, the regular insulation test can be dispensed with – and thus also the temporary shutdown of the circuit. This reduces maintenance effort and minimizes potential operational interruptions.
Advantages of Residual Current Measurement in Data Center Operations
The introduction of an RCM system brings with it a multitude of concrete advantages:
- Early fault detection: Problems can be identified before they become critical.
- Greater operational reliability: Unplanned shutdowns are avoided.
- Less maintenance effort: Shutdowns for insulation testing can be eliminated.
- Compliance with legal regulations: Companies are on the safe side.
Conclusion: Residual current measurement is part of a modern operator strategy
In the highly sensitive environment of data centers, no compromises on supply security are permitted. Residual current measurement is a simple yet highly effective method for permanently ensuring electrical safety, preventing outages, and simultaneously complying with legal requirements. It is therefore not an optional extra, but a strategic tool within the framework of modern energy management. Operators who rely on RCM systems benefit from increased safety, efficiency, and planning security. The installation of appropriate technology should therefore be considered early on – ideally during the planning phase. Only those who continuously monitor their infrastructure can respond quickly and effectively.
Jens Schübel is a state-certified electrical engineer and technical business economist, as well as authorized signatory and technical director at PQ-Plus.
