PRACTICAL ROADMAP FOR ENGINEERS Data center modernization with DC power is no longer theoretical—it is finally happening. The roadmap below reflects what the industry has already validated and where it is heading next: from proven limited-energy Class 2 systems to emerging fault-managed Class 4 topologies that can safely scale power density.
a constant voltage. The reality is that modern DC systems are engineered to be safe, while arc suppression requires sophisticated methods that are often unfamiliar to contractors trained primarily on traditional AC protective devices. This lack of specialized knowledge and training contributed to a perception of complexity. Standards gaps : Until recently, no clear code framework existed for DC beyond ICT voltages. Engineers designing critical infrastructure need well- defined standards, certified equipment, and proven installation practices. The absence of mature standards created liability concerns that deterred adoption regardless of efficiency benefits. Legacy investment : AC infrastructure is amortized, familiar, and deeply embedded. Trained personnel understand AC design patterns, the supplier relationships are established, and installation practices are proven. For most operators, the transition costs and perceived risks outweighed operational efficiency gains. DC distribution worked in showcase deployments. In 2012, Green Datacenter's Zurich-West facility demonstrated 10 percent greater efficiency and 15 percent lower costs with 380 V DC systems. 6 The technology succeeded, but the legacy ecosystem did not.
Fifteen years of "DC is the future" narrative without traction created fatigue. The industry learned to dismiss DC as perpetually five years away while continuing to install AC infrastructure that would lock in conversion losses for another 20 years of equipment life. THE BREAKTHROUGH: LIMITED-ENERGY DC Enter low voltage DC ( ≤ 60 V, ≤ 100 W) and fault-managed DC (up to 450 V, ≤ 3k W per circuit). They are codified under NEC Article 725 and supported by UL standards. 7 The magic? Intrinsic safety and real-time fault detection instead of bulky protective hardware. Low-Voltage DC Powers Distributed Loads Class 2 systems handle the proliferating distributed loads in modern facilities: LED lighting, sensors, Internet of things (IoT) devices, and edge computing nodes running local analytics. These loads consume tens to hundreds of watts, perfect for Class 2's sixty-volt, 100 W envelope. The critical advantage: Class 2 circuits can share cable trays with ICT cabling under NEC 725 guidelines. 8 No conduit required and no heavy-gauge power cables. Standard CMP plenum-rated and CMR riser-rated telecommunications cables suffice for power delivery. Installation resembles structured cabling
more than electrical work, familiar territory for the technicians already deploying edge sites. For thousands of edge locations scattered across office buildings, retail spaces, and industrial facilities, this simplification slashes deployment timelines and costs. Traditional AC would require electricians pulling dedicated circuits, installing junction boxes and outlets, and provisioning circuit breakers. Class 2 leverages the structured cabling workforce, reducing the demand for overburdened electricians. Fault-Managed DC Feeds Medium-Density Racks Class 4 systems bridge to enterprise servers and storage arrays consuming 3 to 12 kW per rack—loads that exceed Class 2 but do not require AI-level power density. Operating safely up to 450 V DC with the ability to send kilowatts of power over a single twisted pair, Class 4 eliminates traditional circuit breakers through continuous real-time monitoring. The term "fault-managed" is used to describe a circuit that continuously verifies circuit integrity through voltage, current, and impedance measurements. The system maintains detailed circuit models and detects deviations indicating insulation degradation or faults in microseconds, faster than mechanical breakers can respond. The implementation of Class 4 represents the cutting edge of power distribution technology. The necessary standards and certification pathways are already defined within electrical codes, providing a clear regulatory framework for safe deployment. Given the superior efficiency, inherent safety, and dramatic reduction in deployment complexity, the value proposition is overwhelmingly compelling for medium-density loads, helping ensure the ecosystem is developing and scaling rapidly to meet demand.
Phase 1: Proven low-density edge loads (Class 2 DC)
This phase is not about testing; it is about leveraging what already works. Class 2 DC power has been successfully implemented in numerous facilities to support low voltage loads such as LED lighting, security cameras, sensors, and IoT devices. These systems routinely demonstrate double-digit energy savings (10 - 25 percent), simplified infrastructure using structured cabling, and drastically reduced maintenance overhead. The results are repeatable: fewer conversion losses, smaller electrical rooms, and safer operation under limited-energy conditions. By standardizing Class 2 across distributed and edge environments, organizations establish a proven, low-risk foundation that builds technical and operational confidence for subsequent phases of DC adoption.
Phase 2: Medium-density infrastructure (5 - 9 kW per rack)
Once Class 2 foundations are in place, the next opportunity is medium-density infrastructure: racks and edge micro data centers drawing between 5 and 9kW. Here, Class 4 fault-managed power systems (FMPS) can safely extend DC distribution to higher voltages to maintain safe operation while delivering greater power and cable lengths. This phase builds on what Class 2 has already proven. The engineering challenge shifts from “can DC work?” to “how do we scale DC efficiently?” Key benefits include reduced copper usage, streamlined power delivery without multiple conversions, and compatibility with renewable and battery-based systems. While widespread Class 4 deployments are still
FIGURE 3 : Cable trays and raceways holding various cables above a data center.
FIGURE 4 : Worker reviewing floor plan designs.
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ICT TODAY
January/February/March 2026
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