Commercial Data Center: Critical Power Distribution

Project Overview

A major cloud services provider commissioned a new Tier III data center in Phoenix, Arizona, designed to house 2,000 server cabinets with a total IT load of 12MW. The facility required exceptionally low voltage drop throughout the power distribution system to ensure stable operation of sensitive computing equipment and to meet stringent efficiency targets. This case study examines the engineering approach used to achieve world-class power distribution performance.

Data centers represent one of the most demanding applications for electrical power distribution. Unlike residential or commercial buildings where voltage drop recommendations of 3-5% are acceptable, data centers typically require total voltage drop of less than 2% from the utility service to the server rack PDU. This stringent requirement exists for two important reasons: equipment performance and energy efficiency.

Modern server power supplies are designed to operate over a range of input voltages, typically 200-240V for international compatibility. However, these power supplies operate most efficiently when input voltage is close to the design optimal point. Lower voltage means higher current draw to deliver the same power to the IT load, which increases heat generation and reduces power supply efficiency. In a 12MW data center operating continuously, even small efficiency gains translate to massive energy and cost savings.

Design Requirements

Power Distribution Architecture

The data center uses a 2N redundant power architecture, meaning every server receives power from two independent paths. Each path includes its own utility feed, main switchgear, UPS system, and distribution infrastructure. If any component fails on one path, the servers continue operating on the other path without interruption. This architecture effectively doubles the power distribution infrastructure and provides numerous opportunities for voltage drop optimization.

The facility receives power at 13.8kV from the utility, which is stepped down through main substations to 480V for distribution throughout the building. UPS systems operate at 480V, and the output is distributed via overhead busway to row-level PDUs. The PDUs transform voltage to 208V for delivery to server racks via under-floor cabling.

Voltage Drop Optimization Strategies

Achieving sub-1% voltage drop in a facility of this scale required multiple optimization strategies applied at each level of the distribution system:

Results and Performance Metrics

Design Your Critical Power System

Planning a data center or critical power installation? Use our voltage drop calculator to optimize your power distribution design and meet stringent voltage drop requirements.