ORV3 HVDC-LVDC 100 kW Power Shelf Design Specification v1.0.0
Open Compute Project · Sanket Sapre, Dmitriy Shapiro et al.
This 2026 OCP specification defines a 100 kW Open Rack V3 power shelf fed from a +/-400 V DC (800 V) high-voltage DC bus that delivers the narrow-range 48 V rack busbar. It reflects the move toward HVDC distribution for AI racks above 100 kW.
On this page
Overview
The shelf uses six 18 kW PSU slots; together they add up to 108 kW, but input power is 100 kW and it is the input connector, not the PSU sum, that sets that limit. With one PSU out, the remaining five deliver 90 kW, so in redundant operation usable power per shelf falls below 100 kW. Input is HVDC at a nominal +/-400 to +/-410 V DC through two 6-pin connectors.
The output is a narrow-range 48 V system, and ripple and noise must stay below 500 mV peak-to-peak. The 48 V return is floating, not bonded to the shelf chassis, which makes the grounding scheme and ground-fault protection an explicit decision in facility design. Busbar clip temperature is monitored with two thermistors, so connector heating can be detected inside the rack and a loosening busbar contact at high current can be spotted early.
The specification is an equipment-level statement of how high-voltage DC attaches to the ORv3 architecture; the upstream rectifier, DC busway and protection design are outside its scope. For those, sources such as the Siemens and NVIDIA paper on 800 VDC protection are needed. The document is one sign of the move toward HVDC distribution for AI racks above 100 kW. The 48 V distribution inside the rack is kept; only the voltage entering the rack changes.
Key points
- Input power 100 kW, limited by the input connector; 6 x 18 kW PSU slots.
- HVDC input: nominal +/-400 to +/-410 V DC through 2 x 6-pin connectors.
- Output: narrow-range 48 V system; ripple and noise under 500 mV peak-to-peak.
- 48 V return floating, not bonded to the shelf chassis.
- Busbar clip temperature sensed with two thermistors.
- Reflects the move to HVDC distribution for AI racks above 100 kW.
Using it in design
- Add an '800 VDC (+/-400 V) to rack' electrical topology option: facility rectification upstream, DC busway, and rack HVDC shelves of 100 kW each.
- Make this option the default for rack-density presets above 100 kW and show a DC arc-flash and protection review warning.
- Record the floating 48 V return grounding scheme and ground-fault protection decision explicitly in project records.
- Model power shelves as 6 x 18 kW per shelf and take the input limit as 100 kW.
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Who should read it
Electrical designers planning HVDC distribution for AI racks above 100 kW.
Related standards
- OCP Open Rack V3
- IEC 60364
- NFPA 70E
Publication details
- Authors
- Sanket Sapre; Dmitriy Shapiro; Zuhir Sras; John Fernandes; Ben Kim; Baby Neil Escuadro; Siu Lam; Mingchun Xu
- Publisher
- Open Compute Project
- Year
- 2026
- Document number
- v1.0.0
- Document language
- English
- Source type
- Industry body
- Access
- Free to read
- Licence
- Copyright retained; citation only — the publisher’s terms apply to the original document
Citation
Sanket Sapre; Dmitriy Shapiro; Zuhir Sras; John Fernandes; Ben Kim; Baby Neil Escuadro; Siu Lam; Mingchun Xu (2026). ORV3 HVDC-LVDC 100 kW Power Shelf Design Specification v1.0.0. Open Compute Project. v1.0.0. https://www.opencompute.org/documents/orv3-hvdc-lvdc-100kw-power-shelf-spec-1-0-0-pdf/
Events on this subject
- Electricity Eurasia 2027
- ELECO 2026 Elektrik-Elektronik ve Biyomedikal Mühendisliği Konferansı
- NVIDIA GTC
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Related sources
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Open Compute Project Foundation 2026
Diablo 400 Project: Rack and Power, Base Specification Version 0.7.0 (effective March 1, 2026)
Check that the facility's AC feed (480, 415 or 400 V, single or dual) and the rack power range match the planned IT block, including up to 1.1 MW per sidecar and the parallel option.
- AC input is 3-phase at 480, 415 or 400 Vrms +/-10%, single feed or dual N+N, 50/60 Hz +/-3 Hz.
Open Compute Project Foundation 2026
Mt. Diablo Disaggregated Power Rack Specification 1.0.0 (effective October 8, 2026)
Add a sidecar power-rack block (600/711 mm wide, about 1200 mm deep, 6000 lb) to AI row layouts with its own floor-load and clearance checks, and model +/-400 VDC distribution from it to IT racks.
- End-to-end efficiency at 480 VAC: >95% at 20% load, >98% at 50%, >97% at 100%.
Open Compute Project Foundation 2023
Open Rack V3 48V BBU (Battery Backup Unit Module) Specification, Rev 1.4
Use 3 kW, 4 minutes and 6 hours recharge as default parameters for ORV3 BBU modules in the rack-power calculator.
- Peak load may reach 150% of rated power; in overload the droop extends linearly (47.25 V at 150% load).
Open Compute Project Foundation 2022
Open Rack V3 BBU Shelf Specification, Rev 1.1
Model ORV3 in-rack BBU as an alternative to a central UPS and check that generator start and transfer time fit inside the roughly 4-minute window at rated load per shelf.
- Each BBU shelf holds one PMI module and six 3 kW BBU modules in 5+1 redundancy.
Open Compute Project Foundation 2025
Requirements/Considerations of Next Generation ORv3 PSU and Power Shelves (OCP EMEA Summit 2025)
Give power shelf catalogue items N+0 and N+1 kW ratings, hold-up time, BBU runtime and allowed peak and pulse-load factors.
- Pulse-load requirement updated for AI GPUs to 160%/136% of rating.
IEEE Access (Institute of Electrical and Electronics Engineers (IEEE)) 2026
Review of the 800-VDC Power Delivery Architecture and Isolated 800-V to 48-V Converter Solutions for Future AI Data Centers
Define 800 VDC unipolar, ±400 VDC bipolar and 48/54 VDC busbar as separate voltage classes in the single-line diagram, each with its own conductor ampacity, breaker pole count and clearance (IEC 60664-1) checks.
- The OCP Open Rack V3 PSU specification targets above 97.5% peak efficiency and at least 96.5% across 30%-100% load.