High-Voltage Power Distribution Units
Power requirements in data centers have entered a period of rapid increase. Workloads that once operated within 10 kW per cabinet now exceed 80 kW, with hyperscale and machine learning environments projecting densities beyond 100 kW. This progression requires delivering sufficient power to the cabinet and mitigating the heat generated as a by-product of these loads.
High-voltage power distribution units (PDUs) distribute 240V or 415V three-phase power to the rack, enabling higher power density within the same footprint. Their deployment helps facilities align with artificial intelligence (AI), graphics processing units (GPUs) and other workloads.
What Is a High Voltage PDU?
A high-voltage PDU is a power distribution unit engineered to manage 240V or 415V three-phase power at server racks. It safely distributes electricity to servers and other equipment inside a cabinet and supplies the high-amperage power required by dense compute environments.
High-voltage PDUs typically deployed by data centers include:
- Basic models: These provide reliable power distribution with circuit protection. They are suitable in environments where monitoring and control are handled by upstream systems or where densities remain moderate.
- Intelligent or managed models: These feature remote outlet switching, power monitoring and predictive analysis. Intelligent PDUs help operators track consumption in real-time and plan for growth, manage loads and reduce the risk of overload.
Why High Voltage PDUs Are Necessary
The need for high-voltage PDUs is a response to the rapid escalation of rack power density. Most cabinets draw less than 10 kW, which could be supported comfortably by conventional 208V infrastructure.
With AI training clusters and GPU workloads, cabinets are often designed for 80 kW to 100 kW, with hyperscalers developing base specifications for densities nearing 175 kW per rack. Neural networks that cater to machine learning settings are designed to approach 1 MW per cabinet.
Supporting AI and Machine Learning Workloads
Training large language models, running neural networks or supporting high-performance computing requires parallelization. The PDU must be able to reliably support the high amperage and continuous duty cycles these workloads require.
Ensuring Power Delivery and Heat Management
Every kilowatt delivered to equipment eventually turns into heat. As cabinet densities scale, operators should consider how to supply enough power and evacuate the thermal load. High-voltage PDUs enable the stable delivery of vast amounts of power in a manageable footprint. Additionally, they reduce line losses and heat in the conductors by operating at higher voltages, contributing to a more efficient system.
How to Increase Power Capacity
As cabinet power requirements increase, operators must find ways to deliver more electricity without creating complexity. Below are strategies that provide scalability.
Move From 208V to 415V Infrastructure
Shifting from 208V three-phase distribution to 415V three-phase effectively doubles a cabinet’s power capacity. This step allows facilities to support higher rack densities without doubling cable size, connector counts or breaker panels. By raising voltage instead of amperage, operators can transmit more power through the same infrastructure while reducing line losses and the associated heat generated in conductors.
Increase Amperage at 208V
An alternative is to increase amperage while keeping the voltage at 208V. For instance, moving from 60A to 125A circuits. This can provide incremental capacity, but there are some considerations:
- Larger cabling may increase installation complexity.
- More complex pathways may be required to route bulky conductors through trays or under raised floors.
- Higher thermal losses can reduce efficiency and create additional cooling burdens.
Strategies to Incorporate High-Voltage PDUs Within Your Infrastructure
Some transitions to high-voltage PDUs occur in operational facilities, which introduce space, cooling and software integration complexities. Teams must carefully plan retrofits and ensure new systems align with existing infrastructure.
1. Add New Connectors, Cables and Busways
As rack loads move from 125A to 175A, facilities can adapt by replacing cables and connectors. The following upgrades ensure the high-voltage architecture remains safe as density continues to increase:
- High-capacity connectors and plugs rated for elevated amperage and designed to maintain reliable connections under continuous high load.
- Thicker, more heat-resistant cables can safely carry the increased current.
- Busways with modular tap-offs provide the flexibility to route high-voltage feeds to cabinets.
2. Ensure Rack and Airflow Management
Without proper airflow or liquid cooling support, the gains in power delivery will be offset by thermal limitations. Design considerations include:
- Increased depth to accommodate servers and GPU chassis.
- Higher weight ratings to support racks filled with dense compute nodes and cooling equipment.
- Integrated airflow and containment features that are essential to channeling hot exhaust air and reducing thermal recirculation.
3. Streamline Flooring and Cable Pathways
Replacing flooring systems and other structural features ensures deployments can operate efficiently. Considerations include:
- Raised floors and cable trays must be engineered to handle the added weight and volume of larger conductors.
- Overhead and underfloor pathways need sufficient space to route thicker cables safely while maintaining accessibility for maintenance.
- Structural loading on raised floors must be reevaluated in environments where power cabling and liquid cooling infrastructure converge.
4. Consider Data Center Infrastructure Management Integration
Intelligent PDUs feature monitoring and control capabilities, but their value is maximized when integrated into a facility’s data center infrastructure management (DCIM) platform. A well-structured DCIM system provides a view of power, cooling and capacity metrics. These capabilities allow operators to track power usage effectiveness and forecast capacity needs. New intelligent PDUs must be evaluated based on their hardware specifications and their ability to integrate with existing DCIM tools and protocols.
Safety and Compliance Considerations
Deploying high-voltage PDUs may introduce risk. Updated protocols, adherence to recognized standards and personnel training can mitigate hazards.
Safety Protocols and Risk Mitigation
High-voltage environments can increase the potential for arc flash incidents, which may occur if energized conductors are unintentionally bridged.
Facilities must exercise proper lock/tagout practices and procedures to ensure equipment is properly deenergized before maintenance. In addition, technicians must be provided with relevant personal protective equipment when working on or near electrical equipment.
Routine inspections and circuit-level monitoring can reduce risk by helping teams identify abnormal conditions.
Staff Training and Compliance
Standards such as NFPA 70E establish the framework for electrical safety in the workplace. Training technical staff under these guidelines can help organizations maintain safe operations. High-voltage deployments should include refresher training programs to keep teams updated as new equipment, tools and protocols are introduced.
Additionally, facilities must comply with relevant local electrical codes, national regulations such as the National Electrical Code and international standards.
Future-Proof Your Infrastructure With DataSpan
DataSpan understands the requirements of power infrastructure and maintaining high-density environments in data centers. As workloads increase power consumption, we are here to help you assess, design and implement solutions to keep loads under control.
With over 50 years of experience, we provide knowledgeable cooling, containment and storage solutions. Our team offers hardware support and maintenance to ensure your infrastructure continues to meet capacity requirements.
Contact us today to learn how we can help your organization.
Links:
- https://dataspan.com/blog/power-distribution-units-pdus/
- https://dataspan.com/data-center/floor-replacement-and-repair/
- https://dataspan.com/data-center/dcim-data-center-infrastructure-management/
- https://www.osha.gov/control-hazardous-energy
- https://www.nfpa.org/codes-and-standards/nfpa-70e-standard-development/70e
- https://dataspan.com/about/
- https://dataspan.com/storage-products-services/hardware-support-service-maintenance/
- https://dataspan.com/contact-us/
About the Author: Alex von Hassler’s long term focus is the continued testing, learning, and deployment of modern IT solutions. During his years as a DataSpan team member, his responsibilities grew from managing Salesforce CRM to improving system security, creating marketing initiatives, as well as providing continued support to the highly motivated and experienced team in an ever-changing industry. As DataSpan evolves to provide the best-fitting IT solutions to its customers, Alex von Hassler continues to hone his skills in the world of web-based ERP systems, security, and best customer engagement practices. Empowering such a dynamic team with the right tools provides him with enormous gratification.
