- ABB, Inc.
- AES
- AES Dominicana
- Alliant Energy
- Alstom Power
- Amec Foster Wheeler
- Ameren
- Ameren Power Company
- American Electric Power (AEP)
- American Electrical Testing Company
- Arizona Public Service (APS)
- Associated Electric Cooperative Inc. (AECI)
- Aurora Generation LLC
- AZZ/Calvert
- B&M Electric Company
- Barnhart Crane & Rigging, Co.
- Basin Electric Power Cooperative
- Bechtel
- Big Valley Electric
- Black & Veatch
- Border States
- Broin & Associates
- Brookfield Renewable Power, Inc.
- Brown Electric Company, Inc.
- Bureau of Reclamation
- Burmeister Electric
- Burns & McDonnell
- Calpine
- CB&I/Shaw Group
- Consumers Energy Company
- CPS Energy
- CV Engineering
- Dahlen, Berg & Co
- Dakota Electric
- Dakota Gasification Co
- Day & Zimmerman
- Delta Star
- Detroit Edison
- DH Blattner
- Dis-Tran Packaged Substations
- Doble Engineering Company
- Dominion
- Duke Energy
- Dynegy Midwest Generation
- Myers Company
- East Central Energy
- East Kentucky Power Corp (EKPC)
- Eaton Corporation
- ECA (Electrical Corp. of America)
- EcoElectrica, LP
- Electric Reliability Services
- Electrical Power Research Institute
- Emerson Process Management
- Energis High Voltage Resources, Inc.
- Energy Northwest
- Entergy
- EPRI
- EPS Technology, Inc.
- EthosEnergy
- Exelon
- Faribault Energy Park
- FirstEnergy Corp
- Florida Power & Light (FPL)
- FLUOR
- Forest City Light & Power
- Forte Power Systems, Inc
- Fountain Valley Power
- FPD Power Development
- GasNatural Fenosa
- GE Canada
- GE Energy
- GenOn Energy
- Grand River Dam Authority (GRDA)
- Great River Energy (GRE)
- Hampton Tedder
- Hawaiian Electric Company, Inc.
- HB Miller Co
- HDR Engineering
- HiCoAmerica
- Holland Energy Center, LLC
- Hooper Corporation
- Hubbell Power Systems
- Imperial Oil, Canada
- Invenergy
- Electrical, Inc.
- JEA
- Kaeding & Associates
- Kansas City Power & Light
- Kelso-Burnett Co
- Kiewit Inc
- L & S Electric, Inc.
- LG Constructors
- Lightstone Generation LLC
- Lockwood Greene
- LS Power
- Luminant
- MEI Electrical
- Metro Power, Inc.
- MidAmerican Energy Company
- Midland CoGen
- Midwest Generation LLC
- Minnesota Management & Budget
- Minnesota Power
- Minnkota Power Cooperative, Inc.
- MJ Electric
- MMPA (Minnesota Municipal Power Assoc)
- MN Municipal Power Agency
- MN Valley Electric
- Moorhead Public Utilities
- Muscatine Power & Water
- Naylor Electric
- Nebraska Public Power District (NPPD)
- New Athens Generating Company, LLC
- New Prague Utilities
- New York Power Authority (NYPA)
- NextEra Energy
- NIMISHA International
- North American Substation Services, LLC
- NRG Energy
- NV Energy
- Oklahoma Gas & Electric (OGE)
- Omaha Public Power District (OPPD)
- Ottertail Power
- Overland Contracting
- Pacific Gas & Electric (PG&E)
- Pacific Power Management
- PacifiCorp
- Panda Patriot
- Parsons Electric LLC
- Payne Crest Electric
- Pennsylvania Dept of Revenue
- Pennsylvania Power and Light (PPL)
- Phillips 66 Company
- Platte River Power Authority
- Plum Point Service Company, LLC
- Powell Canada, Inc.
- Powell, Delta/Unibus Division
- Power Gen Co of Trinidad & Tobago
- Power System Development
- PPL Montour Co, LLC
- Prairie State Generating Company
- Proctor Gamble
- Progress Energy
- Public Service Enterprise Group (PSEG)
- Pung Dairy LLC
- Rochester Public Utilities
- Rockford Power, LLC
- Salt River Project
- Sandow Power Company, LLC
- Sargent & Lundy
- Sempra Energy
- SGL Carbon Group
- Shakopee Public Utilities Commission
- Siemens
- Southern Company
- Southwest Generation
- Spencer Municipal Utilities
- STACE – General Electric Canada
- Standard Industries
- Stanley Group
- STP
- Strategic Equipment, Inc.
- Sunflower Electric Power
- System 3, Inc.
- Talen Energy
- Tampa Electric Co. (TECO)
- Technibus
- Tennessee Valley Authority (TVA)
- Texas Genco
- The State Group
- Three-C Electrical Company, Inc.
- TIC
- Trigen Syracuse Energy Corp
- Tri-State Generation & Transmission
- Tucson Electric
- Turbine Diagnostics Svcs. Inc.
- Turlock Irrigation District
- TXU Energy
- Ulteig Engineers
- Union Power Partners, L.P.
- United Service Group
- US Bureau of Reclamation
- US Dept of Energy
- Utilities Plus Energy Services
- Utility Engineering
- Valencia Power, LLC
- Valmont/Newmark
- Van Ert Electric
- Voith
- Washington Group International
- Watertown Municipal Utility
- Waukesha Electric
- WE Energies
- WESCO Distribution
- Wisconsin Public Service Corp.
- Wunderlich-Malec
- XCEL Energy
