Data Centers Transition to 800V DC: Optimization for AI Workloads
Hyperscale data centers are migrating from AC to DC to support racks with power up to 1 MW. This eliminates multiple conversions, reduces losses, and cuts copper usage. Manufacturers Delta, Vertiv, and Eaton are rolling out direct conversion schemes from 13.8 kV AC to 800 V DC at the data center perimeter.
Traditional power chains involve up to five conversions: from the medium-voltage grid (1–35 kV) through transformers, UPS units, server PSUs, and down to the chips. Each conversion generates 2–5% losses, along with fans and heat. A 1 MW rack requires 200 kg of copper busbars—for a 1 GW data center, that's 200 tons of copper.
Benefits of 800V DC
Direct conversion minimizes stages:
- Reduced heat generation thanks to fewer fans and PSUs.
- Higher reliability: fewer failure points.
- Energy efficiency boost of +5%.
- Smaller equipment footprint.
Switching from 415 V AC to 800 V DC increases cable capacity by 85% with the same cross-section. Current decreases proportionally to voltage (I = P/U), so resistive losses (I²R) drop. The results:
| Parameter | AC 415 V | DC 800 V |
|-----------------|----------|----------|
| Energy per cable| 100 % | 185 % |
| Copper usage | 100 % | 55 % |
| Efficiency | Baseline | +5 % |
| TCO for 1 GW | Baseline | -30 % |
Manufacturer Solutions
Vertiv is developing an 800 V DC ecosystem integrated with NVIDIA Vera Rubin Ultra Kyber, with release in the second half of 2026.
Eaton uses a solid-state medium-voltage transformer (SST) for DC distribution. The SST enables direct AC-DC conversion without traditional transformers.
Delta offers in-row power racks rated at 660 kW on 800 V DC with built-in 480 kW batteries. This is a rack-level solution for rapid deployment.
SolarEdge focuses on SST with 99% efficiency, compatible with DC UPS and distribution.
Technical Implementation Details
In a DC architecture, power is delivered at 800 V up to the racks, where local DC-DC converters (buck type) step it down to 54 V or lower for the chips. This requires reworking PDUs, busbars, and cables.
Key challenges:
- Compatibility with existing racks—adapters or new rack PDUs are needed.
- Safety: 800 V DC is more dangerous than AC due to the lack of zero crossing, requiring enhanced insulators and protection.
- Redundancy: DC UPS is simpler, with batteries connecting directly without inverters.
For AI clusters with GPUs (e.g., NVIDIA Blackwell or Rubin), 800 V DC is critical: a 1 MW rack draws ~1000 A at 1 kV, but 800 V optimizes for standard components.
Key Takeaways
- Direct conversion from 13.8 kV AC to 800 V DC cuts losses by 5–10% and copper by 45%.
- Rack power is scaling from 10 kW to 1 MW, making AC inefficient.
- TCO drops by 30% for GW-scale data centers thanks to smaller cables and equipment.
- 2026 releases: Vertiv+NVIDIA, Delta 660 kW racks, Eaton SST.
- DC boosts density: less space needed for cooling and PSUs.
— Editorial Team
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