# In-rack busbar & power whips

Part ID: 4.15 · Layer 4 (Servers, racks & integration)

The high-current busbar and cabling that carries power from the rack's power shelves to each tray, including Nvidia's specified ±48 V / 1,400 A busbar used in rack-scale liquid-cooled systems.

Busbar and power whips are the last stretch of power distribution inside the rack, carrying current from the power shelves (4.12) to each tray's own board-level power delivery (4.08). A solid or laminated busbar running vertically through the rack, rather than a bundle of individual cables, is what rack-scale systems use to move very high current at the ±48 V level the taxonomy specifies for NVL72-class racks; a bundle of discrete power whips remains the more conventional approach outside that specific architecture. The shift toward busbar reflects how much current a fully populated GPU rack now needs to distribute internally — a level that individual cables handle poorly at scale. For investors, this is a component defined by its current-carrying and thermal-management engineering rather than by exotic materials, and the suppliers building to the Nvidia-spec busbar are working from a reference design that's likely to be revised with each rack generation, which keeps requalification a recurring event rather than a one-time qualification.

**AI delta:** Fully populated GPU racks need to move more current internally than a bundle of discrete cables handles well, which is why rack-scale systems increasingly use a solid busbar rather than conventional power whips.

## Companies

| Company | Role | Confidence | Ownership | Ticker | Note |
|---|---|---|---|---|---|
| Amphenol | manufacturer | reported | public | APH |  |
| Bizlink | manufacturer | reported | public | 3665.TW |  |
| Delta Electronics | manufacturer | reported | public | 2308.TW |  |
| Eaton | manufacturer | reported | public | ETN |  |
| Lite-On | manufacturer | reported | public | 2301.TW |  |
| Schneider Electric | manufacturer | reported | public | SU.PA |  |

Confidence tags: disclosed = company/filing statement; reported = trade press or partner list; inferred = taxonomy lead.