In an Open Rack V3 (ORv3) rack, power passes through four connector jobs: AC input to the power shelf, the shelf's DC output, the vertical busbar that runs up the rack, and the blind-mate connector on each server or node. Each has different current, mating and alignment needs. This guide walks the path in order so you can see which rating matters where.
In short:
- ORv3 distributes 48 V DC over a vertical busbar fed by power shelves, instead of putting a power supply in every server.
- The IT gear connector is rated for up to 100 A per contact in ORv3, up from 75 A in ORv2, according to one supplier's guide.
- Blind-mate connectors need float. The values quoted for shelf output and node connectors are about ±3 mm.
- Ground and sense contacts have special rules, so check mating order and fault current, not only the amp rating.
For rack background, see What is an OCP server? and our Open Rack busbar power connector guide.
Step 1: AC Input to the Power Shelf
Mains power enters the rack through the shelf's AC input connector. One supplier lists 1OU and 2OU versions for wire sizes of 8, 10 and 12 AWG, with the 1OU connector rated for 100 mating cycles and an operating range of -5 to 70 degrees C, and certified to UL 1977 and 62368-1. These are one maker's figures, not a requirement of the specification.
What to check: the wire gauge, the rated current at your ambient temperature, and the safety approvals your site requires.
Step 2: Power Shelf Output
The power shelf converts AC to 48 V DC and delivers it to the busbar. One supplier's output connector for this job is a dual-pole part rated at 1,000 A, which is 500 A per pole, with about ±3 mm of panel float in both directions and integrated chassis ground contacts. Shelf capacity is built from rectifier slots. In the same guide, 3 kW rectifiers fill the slots, so for example 6 plus 6 slots give an 18 kW shelf.
What to check: the current per pole, how much misalignment the connector floats through, and whether the ground contacts are part of the connector.
Step 3: The Vertical Busbar
The busbar is a flat conductor running the height of the rack. The same guide lists vertical busbar configurations from 375 A (18 kW) to 1,200 A (54 kW), with scalable capacity between 300 A and 1,200 A. The busbar is a metal bar, and the connectors are the clips or contacts that take power from it.
What to check: the busbar's current rating, the plating and any galvanic mismatch between the bar and the contacts (see galvanic corrosion in connectors), and how much rack height your load needs.
Step 4: The Blind-Mate IT Gear Connector
Each server or node mates to the busbar when it is slid into the rack, with no one able to see the connection. The same supplier guide describes the IT gear connector as designed for 48 V and rated for 150 A or more, with up to 100 A per contact in ORv3. Other points from that guide:
- Ground: chassis ground contacts must carry twice the rated current for 2 minutes.
- Sense contact: it mates last and breaks first, so power is never live on an incompletely mated connector.
- Float: horizontal float of ±3.0 mm.
- Contact resistance: below 0.55 milliohm.
What to check: the sense contact order, the float range against your rack tolerance, and the contact resistance after repeated mating.
Step 5: Inside the Node
Past the blind-mate connector, power is distributed on the board. The guide lists several board-level power contacts, such as a series rated 140 A per contact at 12.6 mm height above the board, and another at 75 A per contact. Choose by current and by the board height your design allows.
Selection Summary
- AC input: wire gauge, certification and operating temperature.
- Shelf output: current per pole and float.
- Busbar: conductor rating and contact plating.
- Node connector: current per contact, mating order and ground fault rating.
- On-board power: current per contact and mated height.
For a supplier-facing question list, see our ORv3 connector compliance checklist.
Frequently Asked Questions
What voltage does ORv3 use? 48 V DC distributed over the busbar. A supplier guide describes its connectors as designed for 48 V.
What is the difference between ORv2 and ORv3 power? The IT gear connector's rated current per contact rises from 75 A in ORv2 to 100 A in ORv3, according to one supplier's guide.
Why do power connectors need float? Blind mating means the node and busbar are not perfectly aligned. Float lets the connector absorb the offset without bending contacts.
What is a sense contact? It is a short contact that confirms the connector is fully mated. It mates last and breaks first.
Where to Go Next
- Open Rack busbar power connectors: the busbar interface in detail.
- CRPS power supply connectors: the power supply form factor for 19-inch OCP servers.
- OCP and ORv3 connectors hub: all OCP connector guides.
Sources
- TE Connectivity ORv3 power solutions guide: output connector, busbar configurations, IT gear connector and board power ratings. Figures are supplier ratings.