Sub-system
Between the site substation and a processor, power passes through several conversions and protective stages. Each one costs efficiency and equipment, and the whole chain is being redesigned because AI racks draw several times what the previous generation did.
In one sentence
Data-centre power distribution is the chain of switchgear, uninterruptible power supplies, transformers, busways and rack distribution units that delivers conditioned power from the site connection to the equipment.
The traditional chain converts incoming medium-voltage supply down, passes it through an uninterruptible supply that can ride through a loss of source until generators start, distributes it around the hall, and converts it again inside each server. Every conversion loses a few percent, and every stage is equipment with a lead time.
AI racks have broken the assumptions this chain was designed around. A rack drawing over a hundred kilowatts cannot sensibly be fed by many separate cords with individual power supplies; the design moves toward higher-voltage distribution, rack-level power shelves feeding a shared direct-current busbar, and in the largest designs, distribution at higher voltage all the way to the rack.
The chain divides into equipment bought from different industries. What rides through a loss of supply and what carries the load until it returns are two separate purchases, and both are separate again from the distribution running across the hall. The medium-voltage switchgear and transformers at the head of the chain are the same products the grid buys, and are covered with them; the conversion inside the rack is designed by the server maker and is covered with the server.
Split by which part of the chain the equipment belongs to — what carries the load through the seconds, what carries it through the hours, and what distributes it across the hall.
Not to run the site — to bridge the seconds between losing utility supply and generators reaching full output. Traditionally that meant batteries or a flywheel. Increasingly it means lithium batteries with enough capacity to do more: shave peaks, respond to grid signals, or shift a little load, turning a pure insurance asset into one that earns something.
At a hundred kilowatts and more per rack, distributing at conventional voltage means very high currents, which means thick expensive conductors and real resistive losses. Raising the distribution voltage cuts the current proportionally. That is the reasoning behind moving to higher-voltage direct-current distribution within the rack and, in newer designs, to the rack.
Fully duplicated power paths mean each path runs at half load, where conversion equipment is least efficient, and doubles the equipment. Operators running workloads that tolerate a node failure increasingly accept less redundancy in exchange for lower cost and better efficiency — a design choice, not a compromise, when the software handles failure.
1 of these is marked as a chokepoint: a handful of qualified suppliers, a multi-year lead time, or a single geography.
Medium-voltage equipment is on long lead times and has repeatedly been the item that sets a project's completion date.
TransformersLithium systems draw on the same cell supply chain as vehicles and grid storage.
Battery cellsSilicon carbide and gallium nitride switches are what make rectifiers and power shelves efficient at the higher distribution voltages; on silicon devices the losses and the heat they create come back.
Compound semiconductorsAn uninterruptible supply large enough to do more than ride through an outage is a grid storage system in a different building, and it competes for the same cells, inverters and integration capacity.
Utility-scale batteriesOther pages in this map that name Distribution and backup as something they cannot do without.
What each company supplies at this step, and — where a public figure exists — its share of this specific market — with what that share measures, the period it covers and who published it. Some rows also show the company’s own reported revenue for the segment covering this step, which is a different thing: it says how much this business matters to that company, not how much of the market it holds. Not a ranking and not a recommendation.
Supplies uninterruptible power, distribution and thermal management for data centres.
Supplies switchgear, distribution and power management equipment.
Supplies data-centre power and cooling infrastructure.
Supplies electrical connection, protection and liquid cooling products.
Supplies switchgear, breakers and the medium-voltage equipment between the substation and the hall.
Supplies busway, rack power distribution and the last metre of the electrical path.
Supplies power supplies, rectifiers and the shelf-level conversion inside the rack itself.
Supplies transformers and grid-side equipment through the energy business it built out of the ABB acquisition.
Whether higher-voltage direct-current distribution to the rack becomes standard in new AI builds.
Whether uninterruptible supplies are routinely used for grid services rather than only for ride-through.
Whether switchgear and transformer lead times ease from their current elevated levels.
Each page explains one technology in plain language, states what it depends on, and names companies by what they supply at that step. Company roles are described qualitatively and deliberately carry no market shares, revenue figures or rankings — those change faster than an explainer can, and a stale number is worse than none. Ticker links point at company pages on this site and are provided for reference only.
Nothing here is investment advice, a recommendation, or a forecast. A company named on a page about a technology is not thereby a good investment, and the chokepoints described are structural facts about supply chains rather than predictions about prices. Technology moves; where a page describes something as unresolved or in development, that was true when it was written.