A megawatt of air-cooled S21 XP units is about 275 machines. Each one wants roughly 3.6 kW at 220 V, which is 16 A per machine, and there is nothing exotic in the middle. There is just a lot of it, specified correctly or specified late.
The chain, in order
Transformer. Sized to your continuous load with headroom, not to the nameplate sum. Mining is the least forgiving load a distribution transformer sees: flat, continuous, harmonic-rich, twenty-four hours a day. A unit specified for office duty runs hot and ages fast. Ask for a K-rated cast-resin unit — K-13 is the usual answer for mining duty — and size for 1.25× your steady load.
Main switchgear. Incoming breaker, metering, surge protection. This is where you find out whether the utility’s supply is as clean as the contract says it is; put the meter in before the machines, not after.
PDUs. The practical unit is a rack or row PDU feeding 8–12 machines per circuit. Cheap PDUs are the single most common false economy in a hall — they are the part that is under continuous full load for years, and the failure mode is a hot connector rather than a clean trip.
The lead. C19 to whatever your PDU takes, 2.0 m, 3 × 1.5 mm². Order these with the machines, in the standard your site actually uses. A batch that arrives with the wrong plug sits boxed for a week while somebody sources 275 cables locally at three times the price.
The numbers worth writing down before you order
Continuous load per machine, not peak. Total continuous load. Load per circuit and the number of circuits. Cable run lengths — voltage drop over a long run is real, and a machine at the far end of a sagging feed throttles while its neighbour does not. Ambient in the electrical room, which is not the same as ambient in the mining hall.
That list fits on one page and it is the page we ask for before quoting anything above a rack.
The three mistakes we see repeated
Sizing to nameplate. A 3645 W machine does not draw 3645 W; it draws that ±5%, and it draws it forever. A hall designed with no headroom runs its breakers at the top of their curve and trips on the hottest day of the year, which is also the day the derate is already costing you.
Skipping the neutral and earthing detail. Three-phase distribution to single-phase machines needs the phases balanced across the rows. Unbalanced halls waste capacity and produce neutral currents nobody planned for. Balance it on the drawing, not by moving machines afterwards.
Buying power infrastructure last. Transformers run sixty days from order. Switchgear is similar. Machines land in seven to ten by air. If the electrical order goes in after the hardware order, the machines sit in a warehouse burning warranty clock while the yard waits for a transformer.
Ventilation is part of the electrical design
An air-cooled hall moves an enormous volume of air: roughly 3,000 m³/h per machine. That is a building problem, not a machine problem. Negative pressure with filtered intake is the standard arrangement, and the filters are a consumable with a schedule. Halls without filtration lose several per cent of efficiency within a year to loaded heatsinks, and nobody notices because the loss is gradual.
We quote the machines. But we ask for the site drawing first, because a batch of miners delivered to a hall that cannot feed or cool them is not a sale we want to have made.