| 1ST GEN Electric | EC | 2025 | Active |
| 5280 ELECTRICAL Inc. | EC | 2016 | Active |
| A & B Builders | EC | 2014 | Active |
| A R & R Electric | EC | 1986 | Active |
| A.P.Q. Electric Company, Inc. | EC | 1994 | Active |
| A1 Blood Hound Electric Company LLC | EC | 1994 | Active |
| Aaark Heating & Air Conditioning | EC | 1993 | Active |
| AARCO Wireless and Electrical Solutions Corp | EC | 2014 | Active |
| Abacus Electric | EC | 1994 | Active |
| ABM Electrical LLC | EC | 2026 | Active |
| Absolute Electrical, Heating & Cooling, LLC | EC | 2022 | Active |
| Absolute Electrical, Heating & Cooling, LLC | EC | 2023 | Active |
| Accutrol Complete Home Services | EC | 2022 | Active |
| ALD Electric LLC | EC | 2026 | Active |
| All City Electrical | EC | 2025 | Active |
| All Electric LLC | EC | 2017 | Active |
| All Power Electric | EC | 2009 | Active |
| Allstar Electrical Services, LLC | EC | 1987 | Active |
| Alpha Electrical Contracting | EC | 2006 | Active |
| Amon Electric, LLC | EC | 2010 | Active |
| Andreas Electric Co LLC | EC | 2018 | Active |
| Another Electric Company | EC | 1985 | Active |
| Apostolic Electric | EC | 2010 | Active |
| Applewood Plumbing Heating & Electric | EC | 2005 | Active |
| Auxiliary Electrical Services | EC | 2018 | Active |
| Avalon Industries, Inc | EC | 2002 | Active |
| Awesome Electric Ltd. | EC | 2023 | Active |
| B&M Electric LLC | EC | 2022 | Active |
| Bighorn Electric | EC | 2004 | Active |
| Black Hawk Electric & Lighting, Inc | EC | 2000 | Active |
| Blessed Electric LLC | EC | 2023 | Active |
| Bluecore Solar, LLC | EC | 2022 | Active |
| Boa Construction, Inc | EC | 2026 | Active |
| Boss Electric LLC | EC | 2014 | Active |
| Box State Electric | EC | 2025 | Active |
| BriteStreet Solar Built, LLC | EC | 2019 | Active |
| Brothers Plumbing Heating Electrical | EC | 2008 | Active |
| Capitol Hill Electric LLC | EC | 2016 | Active |
| CaRiCO Electric | EC | 2017 | Active |
| Carlton Electric Inc. | EC | 1993 | Active |
| Cascade Solar & Electric | EC | 2020 | Active |
| CDOT Region 1 Tunnels | EC | 2026 | Active |
| Champion Electrical Service LLC | EC | 2023 | Active |
| Choice Electric, LLC | EC | 2022 | Active |
| Chris Electric Inc | EC | 1976 | Active |
| CK Electrical Design LLC | EC | 2011 | Active |
| Clark Hill Electric | EC | 2006 | Active |
| Collins Electric, LLC | EC | 2017 | Active |
| Colorado Department of Transportation | EC | 2012 | Active |
| Colorado Electric And Power Systems Inc | EC | 2003 | Active |
| Colorado Electric Corp | EC | 2021 | Active |
| Colorado Lighting, Inc | EC | 1980 | Active |
| Colpitts Electric LLC | EC | 2022 | Active |
| Computer Sites Inc. | EC | 2000 | Active |
| Conduit Electric LLC | EC | 2020 | Active |
| Connect Solutions Group LLC | EC | 2017 | Active |
| Conquest Electric Inc | EC | 2007 | Active |
| Conserve-A-Watt Lighting LLC | EC | 1992 | Active |
| Control Systems, Inc. | EC | 2004 | Active |
| Correct Electric | EC | 2010 | Active |
| Craft Electric LLC | EC | 2026 | Active |
| Creative Electric Inc. | EC | 1992 | Active |
| Creative Wiring | EC | 1992 | Active |
| Current Electric Inc | EC | 2012 | Active |
| Curtis C Electric Inc. | EC | 2026 | Active |
| Custom Electrical Contractors, Inc. | EC | 1977 | Active |
| D & J Enterprises | EC | 2004 | Active |
| Darbouk LLC | EC | 2025 | Active |
| Dean Electric Inc | EC | 1965 | Active |
| DEC Electric LLC | EC | 2008 | Active |
| Deh Electrical | EC | 2002 | Active |
| Del Electric LLC | EC | 2026 | Active |
| Delmark Electric, Inc. | EC | 1986 | Active |
| Denver Convention Complex | EC | 1990 | Active |
| Denver Correctional Complex | EC | 2005 | Active |
| Denver Electric LLC | EC | 2009 | Active |
| Denver Electrical Contractors, Inc. | EC | 2001 | Active |
| Denver International Airport City & County Of Denver | EC | 1985 | Active |
| Denver Metro Electric Inc. | EC | 2004 | Active |
| Denver Public Schools | EC | 1989 | Active |
| Destiny Electric Service | EC | 1997 | Active |
| Diamond Electric Ltd. | EC | 2023 | Active |
| Diversified Electric & Controls, L.L.C. | EC | 2010 | Active |
| Diversified Electric LLC | EC | 2023 | Active |
| Divine Electric, LLC | EC | 2025 | Active |
| DN Electric LTD | EC | 2025 | Active |
| Donnell Mechanical & Electrical Contracting LLC | EC | 2026 | Active |
| Dunlap Electric Company LLC | EC | 2011 | Active |
| Eagle Electric Co. | EC | 1982 | Active |
| Earth Saving Solutions Corporation | EC | 2025 | Active |
| Efershan Electric, Inc | EC | 2005 | Active |
| Electri-Tec | EC | 1996 | Active |
| Electric Edge | EC | 1992 | Active |
| Electric Excellence Co Inc | EC | 2010 | Active |
| Electro-Flash Services LLC | EC | 2024 | Active |
| Electropolitan LTD | EC | 2011 | Active |
| Elemental Commercial Services, LLC | EC | 2024 | Active |
| Elevated Arc Electric LLC | EC | 2026 | Active |
| Elevated Independent Energy, LLC | EC | 2018 | Active |
| Elevation Staffing LLC | EC | 2017 | Active |