CtrlS Mumbai DC 4 is listed at 36.8 MW of power capacity across 2,936 racks and 265,000 square feet — 12.5 kW a rack and 139 watts a square foot. It is the second densest facility in this registry and the densest large building on the estate. The number worth staring at is the 36.8: every other big figure on this campus is round, and the one that is not is probably the one that was engineered rather than agreed.
1At a glance
2Why 36.8 is better than 36
Forecasts are made of round numbers. Substations, transformers and cooling plants are not.
| Card | Figure | Round? | What it suggests |
|---|---|---|---|
| DC 1 and DC 2 | 40 MW | yes | a design target or a marketing figure |
| DC 5 | 32 MW | yes | a design target |
| DC 4 | 36.8 MW | no | a sum of installed equipment, or a metered design |
| DC 3 | 10 MW | yes | a design target |
| This registry’s cleanest measured figure | 7.4 MW, Hyderabad DC 2 | no | the same signature |
The point is not that round numbers are dishonest — a 40 MW design is a perfectly real 40 MW design. It is that a non-round figure usually comes from somewhere specific: a transformer rating, a generator count, an equipment schedule. Thirty-six point eight megawatts is what you get when you add up what is actually being installed.
For anyone doing diligence, that makes DC 4 the most useful card on the campus. It is the one number an engineer is likely to have produced rather than a marketing team.
Round number: a plan. Non-round number: an installation. Two non-round numbers for the same asset: a document problem — see PRJ-091, where the same building is 4 MW and 6 MW.
This is a crude test and it works more often than it should.
3The top of the density table
Twelve and a half kilowatts a cabinet puts this building in the top four confirmed densities in this registry, and second on a like-for-like basis once the Kolkata outbuilding is set aside.
| Density | What it supports |
|---|---|
| Up to 5 kW | general enterprise, storage, virtualisation |
| 5 to 8 kW | denser enterprise, contained aisles, some HPC |
| 8 to 15 kW | high-performance compute, small accelerated clusters with air or rear-door cooling |
| 15 to 40 kW | accelerated training nodes, requires direct-to-chip liquid |
| 40 kW and above | liquid-cooled AI racks, which is where the new campuses are being designed |
Twelve and a half kilowatts sits at the top of the air-cooling range. It is enough to host a serious accelerated workload and not enough to host the current generation of training racks, which are being specified at 100 kW and beyond. That is the honest description of the gap between what India has built and what the announcements are selling — and DC 4 is on the right side of it for another two or three years.
4What a 12.5 kW rack is for
Practical implications for a buyer, for a vendor and for the operator.
| Reader | What 12.5 kW means |
|---|---|
| A customer needing 2 MW | about 160 racks in this building, or 280 in the older halls on the same campus |
| A cooling vendor | contained air and rear-door heat exchangers; direct-to-chip only at the very top of the range |
| The operator | a building that can be sold to cloud and enterprise but not, today, to an AI tenant without a fit-out |
The interesting strategic question is what happens to this building when the market moves to 40 kW racks. Nothing in the published record says whether the halls were designed with the electrical and cooling headroom to follow, and the answer is worth a lot: a 36.8 MW hall that can be uprated is a different asset from one that cannot.
DC 4 and DC 5 together carry 68.8 MW — 58% of the built campus power on 46% of its racks. Whatever the campus is worth, most of it is in these two buildings.
5Timeline
- The first two campus buildings enter service at 7.2 kW a rack
- DC 3, DC 4 and DC 5 are added as the campus builds out to the substation limit
- The campus substation is doubled to 300 MW with headroom to 700 MW
- The operator lists DC 4 at 36.8 MW, 2,936 racks and 265,000 square feet
- No commissioning date, PUE or occupancy for this building in the public record
6Procurement
7Limits and open questions
8Sources
Sources: CtrlS Mumbai data centre page, CtrlS corporate site, CtrlS datacenters page, Data Center Dynamics on the campus build and on the solar farm, Baxtel Navi Mumbai listings, datacenterlocations, dcmarketinsights, and Indian market commentary on the Navi Mumbai data centre nodes.