Mike Torbitt, Managing Director at Cressall Resistors, explains why true data centre resilience depends not only on securing power, but on ensuring electrical systems respond safely and predictably when faults occur.

The rapid expansion of data centres has placed significant focus on whether electrical networks can provide enough capacity to support growing demand. As operators secure new connections and expand existing facilities, the reliability of the power supply remains a fundamental consideration.

This pressure is set to increase as demand for data centre infrastructure continues to rise. According to Gartner, “electricity consumption from data centres is expected to double by 2030, driven by growing demand for digital services and emerging technologies such as artificial intelligence.”

As facilities scale to meet this demand, electrical systems will need to be designed with greater consideration for how they perform under fault conditions. However, connection availability alone doesn’t determine resilience. Data centres must also demonstrate that their electrical infrastructure can manage abnormal conditions effectively, protecting equipment and maintaining continuity when faults occur.

This is becoming increasingly important as operators face higher expectations from grid stakeholders, insurers and customers. In critical power environments, resilience depends on more than keeping systems operational during normal conditions. It requires a clear understanding of how infrastructure will behave when it is tested.

Designing for faults, not just normal operation

Electrical systems are often designed around expected operating conditions, but their true resilience is determined by how they respond when those conditions change.

Fault events can place significant stress on electrical equipment. High fault currents can create thermal and mechanical forces that can damage components, while poorly coordinated protection systems can increase the risk of unnecessary disruption.

For data centres, where even short interruptions can have significant operational consequences, understanding fault behaviour is becoming an essential part of system design. A robust approach begins with understanding the characteristics of potential faults and ensuring that protection systems and earthing strategies are aligned.

Fault current limitation can help reduce the energy released during fault conditions, limiting stress on electrical infrastructure and allowing protection systems to respond effectively. Fault levels can become more challenging as facilities expand. Additional generation sources, UPS systems and new network connections can increase prospective fault currents, potentially bringing equipment closer to its rated limits.

Understanding these changing conditions is important when planning upgrades or future expansion, particularly in data centres where power systems must continue to support high levels of availability.

Faults are an unavoidable part of electrical systems. The focus should therefore be on ensuring they remain controlled events that can be safely managed without creating wider operational issues.

The importance of earthing strategy

Earthing design plays a fundamental role in determining how electrical systems respond to faults. However, as data centres become more complex, earthing strategies require careful consideration during the design process.

The approach selected will influence how earth faults develop, how protection systems operate and how much stress is placed on equipment. The appropriate approach will depend on several factors, including system configuration, voltage levels, operational requirements and applicable standards.

Neutral earthing resistors (NERs) are one method used within earthing strategies to manage earth fault currents in medium- to high-voltage systems. By limiting the magnitude of current flowing during an earth fault, they can help reduce equipment stress, support protection coordination and provide the conditions required for faults to be detected and cleared effectively.

NERs should, however, be considered as one part of a wider electrical protection strategy. Their effectiveness depends on how they integrate with the rest of the system, including monitoring systems. For engineers designing critical infrastructure, the priority should be creating an approach in which every element of the electrical system contributes to safety and continuity of operation.

Specification decisions shape long-term resilience

A resilient electrical system is built through decisions made long before a facility becomes operational. During the specification stage, engineers need to consider expected fault levels, equipment ratings, protection requirements and future changes to the electrical network. This is particularly important for data centres, where expansion and increasing power demands can introduce additional complexity over time.

Defining these requirements early helps ensure that infrastructure is designed around real operating conditions rather than assumptions. Specification should also consider how performance will be verified. A system that has been designed correctly must still demonstrate that it operates as intended once it is energised.

Why commissioning evidence matters

For critical infrastructure operators, commissioning provides evidence that electrical systems have been installed, configured and tested in line with the design plan.

Testing and documentation provide assurance that protection systems will respond correctly under fault conditions. This evidence can help demonstrate compliance and provide confidence to stakeholders who need visibility of how infrastructure will perform.

The need for this level of assurance is reinforced by the continued impact of electrical failures on data centre operations. According to Uptime Institute’s 2025 Annual Outage Analysis, power-related issues remain the most common cause of serious and severe data centre outages. The findings highlight why operators must look beyond power availability and focus on how electrical systems are designed, protected and validated to respond when faults occur.

Effective commissioning may involve verifying protection settings, confirming earthing system performance, checking equipment operation and ensuring that documentation accurately reflects the installed system. Maintaining clear records also supports future maintenance and operational decisions. As data centres become increasingly important to businesses and wider infrastructure, the ability to demonstrate system performance is becoming increasingly important alongside the design itself.

The demand for data centre capacity is unlikely to slow, but expectations around resilience are evolving. As operators secure additional power capacity, the focus is shifting towards how electrical systems will perform throughout their lifecycle, particularly when faced with abnormal conditions.

A reliable facility depends on a coordinated approach to specification, protection, earthing, testing and maintenance. Each element plays a role in reducing operational risk and ensuring faults can be managed safely without unnecessary disruption.

Ultimately, the challenge facing data centre operators is moving beyond whether enough power can be secured. As fault levels increase and electrical networks become more complex, demonstrating resilience under abnormal conditions is becoming just as important as securing capacity.

The most resilient facilities will be those that can demonstrate their electrical infrastructure is designed to respond predictably when faults occur, supported by clear evidence that systems will perform as intended when it matters most.