Data Center Power Skid or E-House? How to Specify the Electrical Package

A data center power skid combines electrical equipment on a structural base for installation in a prepared location. An e-house supplies an enclosed electrical room containing the agreed equipment and room services. Choose between them by checking who provides environmental protection, cooling, access, fire provisions and the connections to the rest of the facility. Then compare proposals against the same electrical boundary and operating cases.

The enclosure decision can change the building work, transport plan and commissioning responsibilities as much as the equipment purchase. A lower skid price may come with a larger site scope. An e-house can move that work into the factory, while adding a structure that the site must support, permit and maintain.

Before requesting quotations

• Consider an open skid where a suitable electrical room and an achievable delivery route already exist.
• Consider an e-house where the project needs a dedicated electrical space, subject to its environmental and local building requirements.
• State the equipment, operating states and incoming and outgoing terminals before requesting a price.
• Compare the complete installed scope, including room services, field connections, testing and future equipment replacement.
• Require one interface schedule shared by the package supplier, building designer and site contractor.

What does a data center power skid include?

The package can contain uninterruptible power supply (UPS) equipment, switchgear, interconnecting busbar or cabling, controls and other agreed components. The term alone leaves the equipment list open. Schneider Electric's Power Skid, for example, combines UPS, switchgear and controls. That describes a particular vendor offering, which must be checked against the project specification. Schneider Electric Power Skid.

An open indoor skid relies on the surrounding building to provide appropriate protection and working conditions. The equipment can still have its own cabinets and individual enclosure ratings. Anord Mardix describes its Power SKID as an internal installation with factory-interconnected equipment and final commissioning at the site. Anord Mardix Power SKID.

An e-house is a prefabricated electrical room that can contain power and control equipment alongside agreed room services. Eaton describes configurable electrical houses with environmental and auxiliary systems. The actual specification determines which services are included. Eaton electrical houses and skids.

These terms overlap across suppliers. Some open skids use outdoor-rated components. Some enclosed power modules are installed within a larger building. Ask for the arrangement drawing and installation conditions with the quotation.

Which format fits the site?

ABB distinguishes its enclosed e-house solution, with environmental controls, from its open-frame skid solution. That is a useful starting distinction. The buyer still has to define the conditions at the actual installation. ABB integrated modular solutions.

Check access with the equipment maintenance drawings. A cabinet may fit on a layout while leaving inadequate space for withdrawal, replacement or safe operation. Review the doors-open arrangement, cable bending space, lifting provisions and the route to remove the largest replaceable item. The project's applicable rules and manufacturer instructions set the required dimensions.

For an outdoor room, also ask who calculates and supplies the cooling. Electrical losses, solar gain, ambient conditions and component limits belong in that assessment. If cooling fails, the operating response must be understood by the facility team. A room cooling alarm and a loss of protected load are different events with different consequences.

Set the electrical boundary before choosing a package

Draw the proposed package as a box on the single-line diagram. Mark every power connection crossing it, along with earthing, controls, communications and room-service supplies. This drawing makes proposals comparable.

A site-fed UPS skid might begin at the input terminals of its low-voltage (LV) board and end at the UPS distribution outputs. A different supplier may start at a medium-voltage (MV) intake and include a transformer. Those offers need a reconciled scope before price comparison. Show the battery system and maintenance bypass explicitly, including their location, isolation and connection responsibilities. The word UPS alone leaves those package boundaries unresolved. The power-distribution guide follows the wider utility-to-rack path.

For each operating case, establish the output voltage and frequency, required kW and kVA, load power factor, permissible interruption and path availability. Normal operation, maintenance bypass, generator operation and a failed component can create different duties. Upstream protection and downstream distribution must be compatible with those states.

Ask the electrical designer to identify what remains provisional. Available fault current, protection settings, cable data and utility requirements may still depend on studies. The supplier should record the basis used for a quotation and the design information that could change it. Our switchgear procurement guide explains the component ratings and evidence in more detail.

A worked comparison for a first-phase electrical package

Consider an illustrative project adding a UPS-backed electrical path beside an existing data hall. The approved concept places the upstream transformer outside the package. The buyer is comparing an indoor skid with an outdoor e-house. Both must provide the same output duty and agreed maintenance arrangement. The allocation below is a procurement example. The project electrical designer establishes the ratings, protection and operating sequences.

The indoor option uses a room the building contractor must finish. The outdoor option supplies an enclosure with the electrical equipment. Each bid must answer the following scope matrix.

These are example allocations to be negotiated. Compare them with the actual proposals, where the same party may cover several rows. Assign each excluded task to a named contractor and include an allowance in the project budget.

Suppose the skid supplier includes internal interconnections but excludes the incoming cable gland plates. The site contractor has priced cable pulling and termination only. The buyer should resolve who supplies and cuts the plates, who checks cable bending and sealing, and when the final cable schedule must arrive. This small interface can otherwise delay work after the package reaches site.

Now consider the e-house alternative. Its enclosure may solve the room requirement, while the external cable route remains longer. The designer must check that route and its electrical consequences. The price comparison should include the resulting civil work, cable installation and testing. The chosen format changes where the work takes place and which party controls it.

Use an interface schedule to close the gaps

An equipment list identifies what will be supplied. An interface schedule establishes how the supplied equipment becomes part of a functioning facility. Give each interface an owner, input date and evidence required for closure.

Keep the schedule tied to drawing revisions. A later change in the UPS model, battery arrangement or cable route can reopen interfaces previously marked complete. The project team needs to see which decision changed and whose approval is required.

For controls, request more than a protocol name. A supplier can provide a communications port while leaving the facility integrator to configure every point. Agree which alarms, statuses and commands cross the boundary, how loss of communications is detected, and who proves the complete sequence. Operating commands require a defined control authority and commissioning procedure.

How much site work remains after factory testing?

Factory assembly allows agreed equipment and internal connections to be checked before dispatch. Vertiv's prefabricated power offering, for example, describes factory functional testing and integration of power, monitoring and room systems. Vertiv Prefabricated Power Solutions.

Before shipment, agree which tests use the delivered equipment, which rely on simulated external signals and which require the final site installation. Record the evidence for the applicable assembly design verification or product listing separately from the project’s functional tests. A witnessed operating sequence provides evidence for that sequence at its test conditions. Record serial numbers, software versions, settings and open items. Define what evidence permits shipment and what prevents energisation or acceptance.

Site work includes the checks appropriate to transport, reassembly and field connections. The commissioning plan should address connections disturbed in transit, earthing, phasing, actual settings and the complete operating sequences. Test limits and safe methods belong in the approved project procedures and manufacturer requirements.

If a factory test simulates a generator-ready signal, the installed test must still establish that the real generator, controls and load-transfer arrangement operate together as specified. Make that remaining test visible in the contract and programme. This helps the buyer distinguish readiness to ship from readiness to supply the hall.

Compare installed cost and the critical path

Ask each bidder to separate equipment, enclosure, engineering, testing, delivery and site services. Add the receiving project's civil works, room services, external cables, integration and commissioning. Include costs introduced by shipping splits and the eventual replacement route.

Then identify which activities can genuinely run in parallel. Factory assembly may proceed while foundations are built, provided the package loads and connection geometry are released early enough. Component availability, drawing approval and a prepared receiving site can each govern the delivery date. Use dated milestones and named inputs when comparing schedules.

Request a deliverables list with revision status. Useful items include the single-line, arrangement, equipment data sheets, loss schedule, support reactions, termination drawings, control point list and testing plan. For an upstream MV intake or transformer package, use the substation design guide to establish the utility-side inputs before freezing the package specification.

What to send for a useful first discussion

Send the available single-line diagram, installation location, required output duty, resilience objective and target energisation date. Add the site's voltage and known fault data, any preferred equipment, the delivery route and the planned expansion phases. Mark unknown values and identify who will establish them.

ModulEdge manufactures electrical and control assemblies and integrates selected OEM equipment into project power systems. For a proposed package, the next step is to agree its boundary, installation conditions and documentation requirements. Send the drawing and site constraints through Contact. If the power package forms part of a complete facility, the product range provides the starting configurations.

Frequently asked questions

Can a power skid be installed outdoors?

Some assemblies are designed with outdoor-rated equipment. Check the complete installed arrangement, including connections, operating access, weather exposure and environmental limits. For an indoor skid, provide the specified building conditions before installation.

Does an e-house include a transformer and UPS?

The agreed equipment schedule determines the contents. Some packages contain them, while others receive power from separate upstream equipment. Locate both boundaries on the single-line diagram.

Which is cheaper, a skid or an e-house?

Compare the complete installed project cost. A skid may use an existing room. An e-house may supply a room the project would otherwise construct. Cable routes, foundations, environmental systems, transport and commissioning can change the result.

Does factory testing cover commissioning?

The factory test covers the agreed assembled scope and test conditions. The installed facility still needs verification of field connections and the sequences involving actual upstream and downstream systems. Define both scopes before ordering.