Brief · On-site public truth
A data center is a building that has to stay powered and cooled around the clock. On the ground that means a power path (utility feed through switchgear, UPS and generators to PDUs), cooling (CRAH/chillers plus liquid/hydronic loops), fiber trunks and splices, a concrete-and-steel shell, and the people and trucks that install and keep those systems running.
Electricians, HVAC techs, pipefitters, cabling crews and building trades do that work. Where no named filing gives a headcount, megawatt figure or water volume, we leave the number out.
Five pieces. Each one names the trade and the credential employers look for, with links to the deeper pages. No invented counts.
Electricity arrives from the utility, then goes through switchgear, UPS and (usually) generators before it reaches the racks through PDUs.
Heat leaves the building through computer-room air handlers (CRAH), chillers, and: increasingly: liquid/hydronic loops that move heat with water or glycol.
Glass fiber trunks, splices and patch panels are the physical plant that carries data between halls and out of the campus. That plant is low-voltage / BICSI work: not an IT ticket.
Before any rack is live, the building itself has to stand: foundations, slabs, structural steel, walls, roofs, firestopping. That is ordinary commercial construction: general contractors and building trades, not a software release.
A live or under-construction campus is a jobsite: GCs coordinating trades, trade contractors on power/cooling/fiber/shell, deliveries of gear and materials, utility crews on the feed. Who shows up is a “who gets the call” question: not a headcount we invent.
When you write scope or a community presentation, staff by system and put the gate next to the crew. Do not pad:
Full failure map: facility systems · hire matrix: who gets hired · power vs official jobs: jobs vs power · national load vs local rates: grid-load kit · water: water kit.
Every row: what is true, date, primary or DCST authority source, retrieval date. Invented headcounts, MW, gallons, crane counts and rates are omitted on purpose.
| What is true on site | Fact | Context | Date & source |
|---|---|---|---|
| On-site power path (facility, not IT) No campus MW, no invented electrician headcount. | Utility feed → switchgear / UPS / generators → PDUs | Electrician inside; lineworker on the utility feed. NFPA 70E training is employer-common; state electrical license is law. | 2026-11-05 DataCenterSkilledTrades facility-systems + who-gets-hired (authority file) · retrieved 2026-11-05 |
| On-site cooling path No invented gallons, PUE, or tonnage. | CRAH/chillers (refrigerant) + liquid/hydronic loops | HVAC/R opens refrigerant (EPA 608 = federal law). Pipefitter owns facility water/glycol/CDU loops. OEM often services the CDU. | 2026-11-05 DataCenterSkilledTrades liquid-cooling guide + EPA 608 guide · retrieved 2026-11-05 |
| On-site fiber / structured cabling No invented fiber strand counts or splice counts. | Trunks, patch panels, splices: low-voltage / BICSI, not IT | BICSI INSTF is the optical-fiber install credential employers ask for; OR LEA / WA 06 where those states license limited-energy work. | 2026-11-05 DataCenterSkilledTrades BICSI INSTF guide + cert checker · retrieved 2026-11-05 |
| Building shell We deliberately omit crane counts, pour yards, tonnage of steel, and crew sizes: none verified for a generic campus. | Concrete foundations/slabs + structural steel + envelope | Ordinary commercial construction under a GC. Pathways, trays and firestopping serve the power/cooling/fiber systems above. | 2026-11-05 DataCenterSkilledTrades on-site brief (plain construction fact; no primary count source claimed) · retrieved 2026-11-05 |
| Official trade headcount inside NAICS 518200 (data hosting) Do not invent FTE-per-MW or campus trade headcounts from this gap. | Not published (construction employment suppressed; electrician/HVAC/lineworker/pipefitter rows absent) | BLS OEWS May 2025 industry-specific estimates. Most facility trades work for contractors or utilities coded outside 518200. | OEWS May 2025 (released 2026-05-15) BLS OEWS May 2025 oesm25in4 NAICS 518200 · retrieved 2026-11-05 |
| Credential note: refrigerant cooling Required by law. Fee not published by EPA (testing orgs set their own). | EPA Section 608 Technician Certification | Federal law (40 CFR Part 82 Subpart F) for anyone who maintains, services, repairs or disposes of equipment that could release covered refrigerants: CRAH/chillers included. EPA states credentials do not expire. | 2026-11-05 U.S. EPA Section 608 technician certification · retrieved 2026-11-05 |
| Credential note: critical power safety Employer-common: not a substitute for a state electrical license. | NFPA 70E-aligned electrical-safety training (employer-common) | Consensus standard employers use for electrical safety around UPS, switchgear and energized work. Not a license or a single national exam. | 2026-11-05 DataCenterSkilledTrades NFPA 70E checklist (issuer proof footnotes) · retrieved 2026-11-05 |
| Credential note: optical fiber install Employer-common. OR LEA / WA 06 are state law where they apply. Fees handbook-only (left null). | BICSI Installer 2 Optical Fiber (INSTF); TECH broader | When fiber fails, low-voltage/BICSI pathway gets the call, not IT. INSTF validates install, terminate, splice, test, troubleshoot. | 2026-11-05 DataCenterSkilledTrades BICSI INSTF guide · retrieved 2026-11-05 |
Compiled table licensed CC BY 4.0.
Power that almost never fails, cooling that keeps the machines from overheating, fiber that carries the data, a building shell of concrete and steel, and the people and trucks that install and keep those systems running. That work is trades and construction, not a software release.
A general contractor coordinating the job; trade contractors for electrical, HVAC/R, pipefitting, low-voltage/fiber and building trades; deliveries of gear and materials; and utility or lineworker crews on the feed. DataCenterSkilledTrades does not invent headcounts: official OEWS tables for the hosting industry suppress construction employment and omit electrician/HVAC/lineworker/pipefitter rows.
No. Trunks, splices and patch panels are low-voltage / BICSI work. IT owns servers, configs and routing. When fiber fails, the low-voltage pathway gets the call: INSTF is the optical-fiber install credential employers ask for. See /guides/bicsi-instf/.
Both, on different sides. HVAC/R owns refrigerant CRAH/chillers (EPA 608 when the circuit is opened). Pipefitters own facility water, glycol and CDU primary loops. The CDU unit itself is often OEM-serviced. See /guides/liquid-cooling/.
Official data does not say. In BLS OEWS May 2025 for NAICS 518200, construction employment is suppressed and electrician, HVAC/R, lineworker and pipefitter rows are not published. Most trades work for contractors coded elsewhere. We do not invent FTE-per-MW. See /briefs/who-gets-hired/ and /briefs/jobs-vs-power/.
A plain scope of what is physically on site (power path, cooling design, fiber plant, shell), which trades and which employer (owner vs GC vs trade contractor vs utility), dated utility capacity/interconnection and water filings where claimed, and an honest “unknown” where numbers are not in a named filing. Do not accept invented headcounts, campus MW, gallons, or rates. Checklists: /briefs/grid-load/, /briefs/water/.
Do not invent crane counts, pour yards, FTE-per-MW, campus trade headcounts, gallons, or retail rate impacts. Staff the bid by system: power, refrigerant, loops, fiber, shell: and put the gating cert next to each crew. Leave unsourced numbers out.
Cite 'DataCenterSkilledTrades, What a data center needs on site (2026-11-05), https://datacenterskilledtrades.com/briefs/on-site/' and the Dataset 'Data-center on-site systems: power, cooling, fiber, shell, people: verified system/cert facts and honesty rules'.