Every product in this series — switchgear enclosures, transformer cabinets, PDU and control cabinets, generator houses, equipment skids — is metal that eventually has to be wired. Where that wiring happens decides how fast the product goes to work on a data center site. This final post covers integrated electrical assembly: mounting components, running and labeling point-to-point wiring, building harnesses, and bench-testing the finished unit before it ships, all in the same building the metal was made in.
Have drawings for a data center build? Call 601.892.5017 or email collin.t@fabtekindustries.com — we quote to print and respond fast.
- Integrated electrical assembly means the fabricator mounts components, wires to the diagram, builds harnesses, labels and tests before shipment.
- For data centers it is a labor strategy: a wired cabinet turns days of scarce electrician time into hours of landing feeders.
- Specify the bill of materials, wiring diagrams, labeling standard, test procedure and who supplies components — the metal drawing alone is not enough.
- Single-source metal and electrical removes the handoff between a fabricator and a panel shop — one schedule, one fit-up, one test.
- Switchgear Enclosures for Data Centers
- Bus Duct & Busway for Data Centers
- Transformer Cabinets for Data Centers
- Transformer Tanks for Data Centers
- Substation Steel for Data Centers
- PDU, UPS & Battery Cabinets for Data Centers
- Generator & BESS Enclosures for Data Centers
- Cable Tray Supports & Ladder Rack for Data Centers
- Equipment Skids, CDU Frames & Platforms for Data Centers
- Wiring Harnesses & Electrical Assembly for Data Centers (you are here)
What integrated electrical assembly is
A fabricated enclosure is an empty box. Electrical assembly is everything that makes it a product: mounting back panels, DIN rail, breakers, contactors, relays, terminal blocks, power supplies and controllers to the layout drawing; cutting, routing, terminating and labeling every conductor point-to-point to the wiring diagram; building wiring harnesses and cable assemblies for repeat connections; installing door components and interlocks; and inspecting and bench-testing the finished assembly — continuity, insulation, function — against a written procedure. FabTek performs this as contract electrical assembly on enclosures and skids it fabricates, and on customer-supplied enclosures.
Where it lives in the data center
Inside nearly every fabricated enclosure on the campus: relay and control cabinets in the substation, paralleling-gear and generator control panels in the yard, PDUs, RPPs and control panels in the electrical rooms and halls, mechanical control panels in the plant, and the wired blocks on prefabricated skids. The products are described across this series; the wiring is what finishes them. For the electrical chain those cabinets serve, see Inside the Data Center Electrical Room.
What's different for data centers
Two things: labor and repetition. Electricians are the binding constraint on most campus schedules, and wiring done in a shop is wiring the site does not have to staff. And because operators standardize their electrical designs, the same panel layout repeats hundreds of times across a program — exactly the condition under which shop assembly with fixtures, harness boards and a test bench outperforms field wiring on cost, consistency and defect rate. We wrote about the labor side in The Field Crew Labor Bottleneck and the schedule math in Integrated Wiring Assemblies.
What to specify
| Drawings | Panel layout drawing, wiring diagram or schematic, interconnect drawing to field devices, enclosure drawing (or reference to the fabricated enclosure) |
|---|---|
| Bill of materials | Every component with manufacturer and part number; approved alternates; who supplies (customer-consigned vs. fabricator-sourced) |
| Wire & termination | Wire type, gauge and color code, terminal types, ferrules or lugs, torque values, bend radius and routing requirements, duct and tie standards |
| Labeling | Wire-label standard and format, device labeling, nameplates, as-built markup requirements |
| Standards | Applicable listing or standard the assembly must meet (e.g., industrial control panel standards), and any customer workmanship specification |
| Testing | Test procedure and acceptance criteria — continuity, insulation resistance, functional test, point-to-point verification — and required documentation |
| Harnesses | Harness drawings with lengths, breakouts, connectors and pinouts; quantities; packaging |
| Volume & releases | Program quantity, monthly cadence, design-revision control, delivery sequence |
How it's done
The enclosure comes off the finish line and moves — without leaving the plant — to the electrical assembly floor. Back panels are populated on fixtures that hold the layout; wire is cut to length and terminated on harness boards for repeat runs; conductors are routed in duct, labeled to the standard and terminated to the diagram with torque verified. Door devices and interlocks are installed, the panel is set in the enclosure, and the assembly is inspected point-to-point and bench-tested to the written procedure. Test records and the as-built package ship with the unit. Because the same shop built the metal, a cutout that needs to move or a gland plate that needs another hole is a walk across the floor, not a return shipment.
Quality and documentation
Electrical assembly runs under the same ISO 9001:2015 system as FabTek’s metal fabrication: controlled drawings and revisions, documented work instructions, incoming inspection of components, in-process and final inspection with records, calibration of test equipment, and a corrective-action process. For a data center owner or OEM, that means the panel that arrives on site has a paper trail — the same one a commissioning agent will ask for. Our quality page lists the certifications and records available.
Lead time and sourcing
Assembly lead time depends on component availability more than labor; long-lead breakers and controllers should be ordered or consigned early, and the fabricator should be told which items are critical. For repeating programs, the sourcing model is the same as the enclosures themselves: a dedicated line with reserved capacity, frozen design revisions and monthly releases. The single-source case is straightforward and we made it in Single-Source Datacenter Power: metal and electrical from one building is one schedule to hold, one fit-up to get right, and one test before the unit reaches a site that has no hours to spare.
That closes the series. If you have drawings for any of the ten products covered — or a one-line and a transformer date you are building toward — send them over and we will tell you what we can build and when.
FabTek Industries fabricates integrated electrical assemblies, panel wire-out and wiring harnesses for the enclosures, cabinets and skids it fabricates and for customer-supplied enclosures to print for data center, EPC, electrical contractor and OEM customers — components mounted to the layout, point-to-point wired and labeled to the diagram, harnesses built on boards, and every assembly inspected and bench-tested to a written procedure — under an ISO 9001:2015 quality system with AWS-certified welding, from four production sites in Hazlehurst, Mississippi, shipped nationwide. Dedicated production lines with reserved monthly capacity are available for recurring volume, and our field crews handle on-site installation and commissioning support. Send us your drawings or call 601.892.5017.
Frequently asked questions
What is integrated electrical assembly?
The fabricator mounts components to the panel layout, runs and labels point-to-point wiring to the diagram, builds harnesses, installs door devices and interlocks, and inspects and bench-tests the completed assembly before it ships — all in the same facility that fabricated the enclosure.
Why should data center cabinets be wired before delivery?
Licensed electricians are the scarcest resource on a data center site. A cabinet that arrives wired and tested turns days of on-site work into hours of landing feeders and field wiring, and removes the handoff between a metal fabricator and a separate panel shop.
What documentation should ship with a wired assembly?
As-built drawings, the bill of materials, wire-label and device-label lists, inspection records and the completed test report per the specified procedure, along with material and certification documents for the enclosure itself.
Does FabTek wire customer-supplied enclosures?
Yes. FabTek performs contract electrical assembly on enclosures and skids it fabricates and on customer-supplied enclosures, under its ISO 9001:2015 quality system, with components either consigned by the customer or sourced by FabTek.
