What is a prefabricated electrical assembly?

prefabricated electrical assembly  is a fully customisable and factory-integrated solution for electrical control and power distribution. Prefabricated assemblies integrate multiple pieces of electrical equipment into an enclosure or skid and can be designed for stand-alone construction. These pre-built power systems increase project productivity by helping to shorten timelines, simplify project management and reduce installation time and cost. Compared to customary brick and mortar construction, prefabricated assemblies are often the most economical choice to meet project demands. 
In addition, prefabricated electrical buildings or skids are typically applied when:
  • Space is limited due to cost or availability  
  • New or incremental electrical equipment is required  
  • Electrical systems are located in a remote area or separately from the main facility  

Prefabricated electrical assemblies can also significantly reduce project management requirements. On-site coordination and installation problems are minimised or eliminated because all equipment is installed, tested and ready to use upon delivery. 

To make things simpler, prefabricated electrical assemblies can be custom-built, constructed, tested and inspected. This streamlined process is typically significantly more efficient than on-site construction and coordination.  


Why use a prefabricated assembly?  

There are hosts of advantages to consider when deciding between traditional and prefabricated electrical assemblies. 

  • Less on-site labour 

Prefabricated assemblies are factory constructed, with electrical equipment wired and tested to minimise on-site labour costs, quality issues and time. 

  • Simplified project management 

Prefabricated assemblies can significantly reduce the potential impact of various equipment delivery schedules and multiple construction trades accessing the worksite. 

  • Streamlined power system component integration, commissioning and testing  

With start-up and commissioning test plans being combined with in-depth factory testing, prefabricated electrical assemblies arrive ready to manage all anticipated normal and emergency operating conditions. 

  • Reduced physical footprint  

Each assembly is engineered to use as little space as possible while meeting unique application needs. Most solutions can fit on a platform or trailer, making transport and space requirements manageable. 

  • Future expandability

Unlike traditional construction, prefabricated electrical assemblies offer a flexible, expandable design that can be connected to additional units to meet changing needs. 

  • Accelerated asset depreciation

Prefabricated assemblies can be depreciated faster than traditional brick and mortar builds in the USA, according to IRS publication 946. Prefabricated assemblies can be depreciated in seven years, compared to 39 years for equipment installed in the facility

Enclosed or skid – find out what works for you 

Whether single-unit, multi-story, walk-in or non-walk-in, prefabricated electrical assemblies provide a solid foundation for electrical control and power distribution. Construction details are engineered to ensure that both customer specification and building codes are met for each installation. 

Enclosed electrical assemblies can be customised with climate control and blast-resistant enclosures to meet the required ratings for hazardous environments including Class 1 Division 2, or when traditional indoor equipment needs to be located outdoors. Rated for reliable performance in extreme environmental conditions, enclosed electrical assemblies can be applied in conditions where wind, snow, seismic activities or harsh temperatures occur. Customised components can also be integrated into enclosed assemblies, including HVAC systems, power back-up equipment or personnel workstations

Integrated Power Assemblies (e-house)
Enclosed E-house
Modular integrated transportable substation
Skidded solution

Skidded electrical assemblies are a plug-and-play solution that mounts all necessary electrical equipment onto a base that can be delivered to a designated location for quick, safe and easy installation. Whether a fully integrated electrical control room or a power distribution centre, skid assemblies can be configured for indoor or outdoor applications.

Skidded designs can be incorporated into existing buildings and configured for nearly any application. For example, preassembled substations can be applied in remote oil and gas production sites, on campus-type commercial settings or at utility distribution substations and distributed-generation sites. The flexible, expandable design allows for a variety of customised equipment configurations and can even be connected to other modules to form larger, more complex electrical systems. Designs can also be standardised to easily accommodate future modification. 

The different types of prefabricated electrical assemblies include: 


What is an E-house?

An electrical house or E-house is a fully customisable, prefabricated, integrated power assembly that contains industrial control and power distribution equipment. Design, construction, quality inspection and testing of the solution are all completed in a controlled manufacturing setting prior to being delivered to a worksite.   

An electrical house can include a wide variety of electrical equipment and meet additional operational needs. For example, E-houses can support HVAC systems, personnel workstations and back-up power system requirements.

IPA main photo

How is an E-house built? 

E-houses are constructed using a quarter-inch (6mm) thick floor plate welded to a C-channel base. This solid foundation for internally mounted components enables installation on either a concrete pad or raised piers. Exterior walls are formed, interlocking panels, typically constructed from painted, galvanised steel, aluminium or stainless steel, but can also be made from other materials to extend the life of the structure, including pre-coated, corrugated Galvalume steel, concrete or fibreglass. Building aesthetics can be enhanced with flashing and trim and side walls can be modified to accommodate penetration, as required.   

Where can an E-house be applied?

E-houses can be applied across many industries and applications. They are often chosen over traditional brick and mortar construction because of the positive impact on project productivity. Using an E-house can simplify project management and coordinating equipment, saving time and money.   

E-houses are also a good fit for applications requiring equipment that is not rated for the location’s environment. For example, e-Houses can be built to NEMA 3R standards, which provides a rain-tight enclosure.  Additionally, E-houses can be built to operate in harsh or hazardous environments (as defined by NFPA 70 – Class 1, Division 1, Groups A, B, C and D), to meet additional ratings and to address environmental conditions.

Concrete building

What equipment can be integrated into an E-house?


Mobile substations

What is a mobile substation? 

Modular, integrated, transportable substations are a turnkey, engineered, power distribution substation solution, designed to meet the specific needs of each application and used for both temporary and permanent power needs. Modular substations can provide a complete packaged solution – saving cost, time, space and labour when the time comes for a new or replacement substation, distribution centre or simply to add capacity to an existing substation.

How is a mobile substation built?


Mobile substations are factory-assembled, wired and tested to minimise on-site labour costs, quality issues and time. This includes on-board protection, control and automation devices. The entire mobile configuration can be mounted on a trailer, making it a “ready to roll” electrical power distribution solution with the capability to be quickly energised. These can be used for emergency and other temporary power needs or applied in the long term.

The flexible, expandable design of mobile substations allows a variety of equipment configurations for various applications. Modules can be connected together to form more complex substations and designs can be standardised to easily accommodate future modification.

To simplify on-site labour, a fence is not needed when a dead-front design is used. Additionally, the solution is less susceptible to environmental damage when constructed using shield-grounded, medium-voltage cable.

Where can a mobile substation be applied?

Mobile substations can be configured for industrial, commercial and utility applications, including:

  • Industrial – oil & gas production and transmission sites, mining operations, manufacturing and assembly plants, petro-chemical plants and drilling rigs. 
  • Commercial – campus-style or distributed facilities, such as general office space, higher education campuses, laboratory/research centres, data and telecommunication tower sites and facilities, health care complexes, correctional institutions, military facilities, gaming/entertainment facilities (casinos and theme parks), transport facilities (airports, transport stations), “intelligent” highway service power and harbourside power. 
  • Utility – distribution substations, industrial power parks, rural/agricultural services and distributed generation sites, regulation stations, switching stations and mobile equipment. 

What equipment can be incorporated into a mobile substation?


Any medium-voltage power distribution and control equipment can be included in a mobile substation, including but not limited to:

To find out more, take a virtual tour around the inside and outside of an actual mobile substation. Each component includes pop-up information.

Modular data centres (MDCs) 

What is a modular data centre or MDC?

With an easily scalable design developed to your specific needs, modular data centre solutions are custom-engineered to site-specific infrastructure requirements. A modular data centre or MDC combines server space with electrical and environmental equipment in a compact enclosure  – reducing complexity, speeding deployment and delivering optimum efficiency and the lowest cost throughout the life cycle of a data centre.
Modular data center

How is a modular data centre built?

Modular data centres are constructed to provide scalability and flexibility as business and IT needs evolve. Configurations for turnkey modular data centre solutions include all-in-one data centres or critical support infrastructure such as integrated equipment skids and/or modular power assemblies.

For example, the Eaton all-in-one data centre is a single container with IT equipment racks, UPS, switchgear, batteries, HVAC units and all associated fire and safety equipment inside.  

Where can a modular data centre be applied?

Modular data centres can be deployed quickly to expand existing data centre white space capacity, incorporated into greenfield modular facilities or used in disaster recovery situations. Thanks to their compact design, MDCs offer multiple deployment options, such as in a car park, loading dock or warehouse, to preserve valuable existing property.

What equipment can be integrated into a modular data centre?

Interior 1.jpg

An MDC can contain all the hardware required for a fully functional data centre, including:

  • N, N+1 and 2N power and cooling system designs 
  • Multiple and configurable server rack space 
  • Custom-built power and cooling capacity to meet customer needs
  • Fire detection and/or suppression options 
  • Air or water-cooled options available with “free cooling” modes using airside economisers 
  • Single or dual-corded load options 
  • Integrated monitoring solutions 
  • Back-up generator modules
  • Larger centralised UPS systems
  • Chiller modules

Substation power centre

What is a substation power centre?

substation power centre is a custom-built, sheltered-aisle, outdoor, metal-clad switchgear enclosure for utility and substation applications, combining distribution and controls in one enclosure. This solution has powerful operational and integration efficiencies.  

Unlike most standard, outdoor-rated enclosures for switchgear, substation power centres provide insulated walls, a welded steel frame and the ability to integrate control systems.  They enable operational flexibility, with the ability to choose how and where cables enter the distribution equipment and options to locate cabling at the roof-mounted bushing, through the wall or from the bottom of the enclosure.

Common substation power centre configurations include 5–15 kV, 27 kV, 38 kV and 5–15 kV arc-resistant construction up to type 2C, using welded compartment construction for maximum reliability and environmental dependability. The switchgear is constructed to the IEEE C37.20.7 type 2c arc-resistant standards.


How is a substation power centre built?

OPC power center trailer

Substation power centres feature switchgear assemblies designed as an integral part of the outdoor housing. Switchgear cubicles use welded 11-gauge construction to ensure that the enclosure remains “square” and that breakers rack in correctly over the life of the switchgear. Individual structures are then bolted together to form a continuous line-up.

The exterior roof and wall panels are formed of 11-gauge steel sheets to create a self-framing structure. Roof caps – also made of 11-gauge steel – cover each roof panel joint for a permanent weather seal. The wall panels are formed, bolted together and mounted on a structural channel base with steel plate welded in place to create the floor. For further durability, the doors are made with double returns and welded edges to prevent warping and to ensure that latches operate correctly

Outdoor switchgear power centres provide a temperature and humidity-controlled environment for protection of critical electrical equipment. These configurations also include:

  • A custom-built, structural steel base that allows installation on pad, pier or perimeter foundations; existing foundations can be re-used
  • Corrosion-resistant epoxy base coating
  • A high-quality powder coat finish for superior performance
  • IEEE-tested enclosure that ensures weatherproof integrity

Where can a substation power centre be applied?

Substation power centres provide robust, centralised control and protection of power equipment in utility, industrial and commercial applications. The custom-engineered switchgear is designed to exceed IEEE switchgear design and manufacturing standards.  

What equipment can be integrated into a substation power?

A range of solutions can be integrated into substation power centres to ensure the configuration meets the specific needs of your application and environment. Options include, but are not limited to: