• • • DATA CENTRES • • •
ELECTRICAL RESILIENCE IN DATA CENTRES: HOW CONTROLLED FAULT CURRENT AND RESISTIVE TECHNOLOGIES ENHANCE UPTIME AND SYSTEM STABILITY
BY MIKE TORBITT, MANAGING DIRECTOR, CRESSALL RESISTORS D
ata centres are the backbone of the digital economy, supporting everything from cloud computing to artificial intelligence and global communications. As demand continues to rise, so does the requirement for uninterrupted operation. Mike looks at how system-level electrical design strategies including controlled fault current management and seamless power transfer can help improve resilience and reduce the risk of costly disruption in data centre environments. Despite advances in redundancy and backup systems, power remains the leading cause of major outages. According to the Uptime Institute’s 2025 Annual Outage Analysis, ‘power-related issues remain the leading cause of significant data centre outages, reinforcing the need to address electrical resilience beyond traditional backup strategies.’
The scale of the challenge is increasing. The International Energy Agency estimates that global data centre electricity demand could exceed 1,000 terawatt hours by 2030, driven largely by artificial intelligence and digital services. As electrical loads increase, infrastructure is pushed closer to its limits, making system stability during abnormal conditions more critical than ever.
Why fault behaviour matters Electrical faults within a data centre can introduce rapid changes in current and voltage that place stress on equipment and protection systems. In environments where uptime is critical, even short disturbances can trigger unnecessary trips or disrupt sensitive operations.
20 ELECTRICAL ENGINEERING • MAY 2026
This challenge is compounded by the increasing use of inverter-based technologies and complex distribution architectures. These systems can behave differently under fault conditions compared to traditional designs, sometimes reducing available fault current and making protection coordination more difficult. Without controlled fault current behaviour, systems can either overreact or fail to detect faults reliably, increasing the risk of instability and unplanned downtime.
Managing fault current for system stability
Improving resilience requires a more controlled approach to fault current management. This reduces stress on transformers, switchgear and cabling while ensuring protection systems respond predictably. This is particularly important during earth fault conditions and transitions between power sources such as grid supply, UPS systems and standby generation.
Neutral earthing resistors (NERs) provide a proven method of controlling earth fault current in power systems. By introducing a defined resistance between the system neutral and earth, they limit fault current to a safe and predictable level while maintaining a stable reference point for the system.
This controlled approach allows protection systems to detect and respond to faults without forcing immediate disconnection. In high-resistance grounded systems, a first earth fault can often be managed as an alarm condition, allowing operators to identify and resolve the issue without interrupting service. For data centres, NERs must be designed to reflect real-world operating conditions including system voltage, fault current requirements and thermal duty. Considerations such as footprint, cooling and compliance with electrical standards are also critical to successful integration.
Supporting seamless
power transfer Transitions between power sources represent some of the most critical moments in a data centre electrical system. Whether switching from grid to generator or between supply paths, these events can introduce transient conditions that affect system stability.
If fault current behaviour is not properly controlled, switching events can result in voltage fluctuations or protection miscoordination, increasing the likelihood of nuisance tripping. By maintaining stable fault current levels and system reference conditions, well-designed earthing strategies support smoother transitions and reduce the risk of disruption during these events.
Towards a more resilient
electrical architecture As data centres continue to expand, resilience depends on how electrical systems behave under fault and switching conditions. Controlled fault current strategies that maintain system stability and ensure predictable protection response are becoming central to modern data centre design. These factors play a direct role in preventing outages and protecting critical infrastructure. For operators and designers, the focus is shifting towards a more holistic approach where electrical resilience is built into the system from the outset rather than added as an afterthought. The demands placed on data centres mean that uninterrupted operation is no longer optional. As critical national infrastructure, these facilities must be designed to perform reliably under a wide range of conditions. By incorporating controlled fault current strategies and technologies such as NERs, engineers can reduce system stress, improve protection performance and support seamless transitions between power sources.
www.cressall.com
electricalengineeringmagazine.co.uk
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