800V DC data centre power
The reference for practitioners on the 800V DC transition: architecture, standards, vendors, and economics. Anchored by NVIDIA + OCP Mt. Diablo v0.7.0 (March 2026) as the AI-density baseline; extended by IEC + UL + NEC in-progress work for 1500V DC and MVDC futures.
01Direct answer
02Key concepts
03Structural decomposition
The six-layer AI power stack
- Layer 1. Utility interface + BESS (medium-voltage AC feed; grid-facing)
- Layer 2. Perimeter conversion (MV AC to 800V DC via solid-state transformer)
- Layer 3. Building distribution (800V DC bus + switchgear)
- Layer 4. Rack-level conversion (800V DC to 48V DC via sidecar power rack)
- Layer 5. In-rack distribution (48V busbar to compute blades)
- Layer 6. Point-of-load (48V to sub-1V @ die via POL silicon)
04Deep-dive research
- The Architecture MapFoundational six-layer framework for the entire series.
- 800V DC vs OCP Mt. DiabloTwo distinct architectures both called "800V DC" and how to tell them apart.
- Why data centres are going DCThe efficiency + reliability drivers beyond capacity.
- Arc behaviour + insuranceLayer 3 protection regime and the insurance underwriter constraint.
- Supplement A. The Transition TaxLayer-by-layer capex premium decomposition.
- Supplement B. Hybrid ForeverWhy most facilities will run mixed AC/DC through 2035+.
- Supplement C. The Voltage Ceiling1500V DC and the MVDC question.
- Supplement D. The Solid-State TransformerLayer 2 supplier dynamics: Western vs Chinese SST.
- Supplement E. The Sidecar Power RackLayer 4 architecture + OCP Mt. Diablo ecosystem.
- Supplement F. The Connector WarsLayer 4/5 interface: high-current DC connectors.
- MVDC / LVDC Architecture MapLiving index of vendor coverage across DC voltage classes.
05Standards + regulation
- OCP Rack + Power (Mt. Diablo v0.7.0)Current reference specification for 800V DC AI-density rack architecture.
- IEC 60947-10 (SSCB), IEC 62477-1, IEC 60364-7-712International safety + protection standards; 1500V DC extensions in progress.
- UL 98B (DC disconnects), UL 1741 SB (grid interconnection)North American safety certification; 1500V DC extensions in progress.
- NEC 2026 (NFPA 70)Adds partial 1500V DC coverage in 2026 edition. State adoption rolling through 2026-2028.
06Commercial + investment implications
Commercial + investment angles
The 800V DC transition is a specific capex + supplier-concentration lens on AI infrastructure. See Supplement A: The Transition Tax for layer-by-layer capex decomposition and Supplement D: SST vendor dynamics for the specific Layer 2 supplier concentration risk. For PE sponsors evaluating power-electronics or SST acquisitions, this is the primary market thesis. For hyperscaler strategy teams specifying facilities that commission 2027-2029, this is the primary architecture decision.
07Frequently asked
Why 800V and not another voltage?
800V is the specific voltage where AI-density economics work: high enough to reduce copper cost + conversion stages materially vs 480V AC baseline, low enough that Western insurance underwriters + skilled electricians can accept it today. 1500V DC offers further copper reduction but faces standards + workforce readiness constraints (see Supplement C).
Is 800V DC the same as OCP Mt. Diablo?
No. 800V DC describes the voltage class + broader architecture; Mt. Diablo (v0.7.0) is one specific reference implementation for the Layer 4 sidecar power rack. NVIDIA reference designs assume 800V DC facility feeds; Mt. Diablo specifies how Layer 4 (rack-level) is built to accept those feeds. See Two Architectures Wearing the Same Name.
When will 800V DC be mainstream for new AI data centre construction?
2027-2029 for hyperscaler AI-density greenfield. Earlier for high-density pilots (2026). Later for mid-cap operator + colo (2028-2030). See DC-DC Transition XIII: Ten-year view.
What is the biggest supplier-concentration risk?
Solid-state transformers (Layer 2). Four Western vendors (Eaton, Schneider, ABB, Hitachi Energy) have disclosed SST development or products, alongside three Chinese entrants (CRRC, TBEA, BYD). Data-centre commercial availability and hyperscaler qualification status vary substantially across the set; this is a supplier map, not a shortlist. See Supplement D.
Where does 1500V DC or MVDC fit?
Mid-to-long term. 1500V DC offers ~30% additional copper savings vs 800V DC but faces standards (IEC 60947-10, UL 98B extensions in progress), workforce, and insurance constraints. MVDC (5-15 kV) is campus-scale utility distribution, not in-facility. See Supplement C.
How does 800V DC change insurance + safety?
Materially. Arc behaviour at 800V DC is different from 480V AC (see DC-DC IV: Arc Behaviour + Insurance). NFPA 70E arc-flash guidance applies but DC-specific insurance underwriter acceptance is the practical gating factor.
08Further reading
| Standard / architecture | Sponsor | Topology | Status | Vendor design-wins |
|---|---|---|---|---|
| OCP Mount Diablo 400 v0.7.0 | Microsoft + Meta + Google | Bipolar ±400V default (unipolar 800V configurable) | Published 1 March 2026 | Delta, Vicor, Vertiv, Schneider |
| Nvidia 800V (Blackwell/Rubin) | Nvidia | Unipolar 800V DC (0-800V rail) | Production spec 2025-2026 | Delta, Vicor, Empower Semi, MPS |
| Legacy 415V AC (comparison) | IEC / IEEE | Three-phase AC | Existing (mature) | Universal |
| HVDC facility distribution (adjacent) | None (custom) | ±10 kV DC (facility-to-substation) | Research / pilot | ABB, Hitachi Energy, Siemens |
Navitas Semiconductor: The $3B Kyber Bet
Vendor-level treatment of the 800V direct-to-rack architecture. Nvidia's twelve-name 800V silicon ecosystem, per-rack GaN content in 48V hybrid racks vs 800V native Kyber racks (~$80-240 vs ~$250-600), the 133:1 duty-cycle physics that makes single-stage 800V-to-6V a real engineering challenge for anyone, the qualification gauntlet that separates a GTC demo from a production design win, and the specific reason why "on the partner list" is a starting line rather than a design win. Direct companion to Grid-to-Chip P4 Hall power and P5 Rack to Gate.