Every data center campus and every utility interconnect runs through a substation. These are the firms that design and build them across the US: the EPCs who can take a project from engineering through energization, and the electrical contractors who self-perform the field work.
A quick primer before the lists: what a substation does, who owns which piece, and how an EPC's job differs from a contractor's.
A substation takes high-voltage power off the grid, protects it, and steps it down to a voltage a campus can distribute.
A large campus usually involves two substations with different owners. The point of interconnection is where one ends and the other begins.
The difference is how much of the project one firm owns, and how much risk it takes on.
The substation is only the first step down. Inside the campus, power is stepped down again at each building before it reaches the servers.
Engineer, procure and construct under one contract. These firms are active on both utility substations and data center interconnects or owner-built campus substations.
Long-time leader in T&D design with full substation EPC delivery, including data center transmission projects.
Dedicated data center substation practice alongside decades of utility substation EPC work.
One of the largest design-build firms in the country, with in-house power delivery engineering and craft labor.
Utility engineering plus the largest self-perform workforce in the industry; Cupertino Electric covers mission-critical work.
Power Delivery segment delivers substation and interconnect EPC for utilities, renewables and large loads.
Utility segment builds substations and interconnects for utilities, solar and battery storage projects.
EPC or construct-only substations from 34.5 kV to 765 kV through Sturgeon, Harlan and other subsidiaries.
Substation specialist with in-house protection and control engineering, strong in ERCOT and the Southeast.
Substation EPC and P&C for utilities, with growing large-load interconnect work.
Newer to the space, delivering EPC substations for hyperscale data center campus expansions.
OEM turnkey substations: Hitachi Energy, Siemens Energy and GE Vernova deliver complete substations bundled with their own transformers, GIS and breakers. They are often the fastest path when equipment lead time is the constraint.
Design-only engineers: POWER Engineers (WSP), Sargent & Lundy and NV5 design many of the substations the firms on this page build.
Firms that self-perform utility and high-voltage substation construction: foundations, steel, bus, equipment setting, P&C wiring, testing and commissioning.
Largest electrical contractor in the US, operating through dozens of regional companies.
National power delivery, renewables and communications infrastructure contractor.
Decades among the top electrical contractors; substations up to 765 kV.
Large utility services segment spanning substations, lines and storage interconnects.
Family-owned national contractor with a dedicated substation and BESS group.
Self-performs substation and transmission construction for major utilities.
Builds as well as designs, with self-perform capability through AZCO.
Construction arm active on utility and data center substations.
Major Southeast utility contractor covering substations, lines and engineering.
Mission-critical electrical leader with a high-voltage and utility substation group.
Self-performs complete substation scopes, electrical and foundations.
Mid-Atlantic substation builder on Dominion and ODEC approved lists.
Substation construction with in-house P&C engineering.
Dedicated substation department working up to 500 kV, Rockies to Florida.
Substation EPC and T&D across the Northeast and Mid-Atlantic.
Formerly Signal Energy and Applied High Voltage; substations and HV lines for power, industrial and data center markets.