| 2 - K Electric Inc | C10 | 2023 | Active |
| 21st Century Sterling Inc | C10 | 2002 | Renew by Dec 31, 2026 |
| 2m Electric Inc | C10 | 2022 | Active |
| 3 D Electric Inc | C10 | 2019 | Active |
| 3b Group LLC | C10 | 2024 | Active |
| 3cab Electric Inc | C10 | 2024 | Active |
| 503 Electrical | C10 | 2026 | Active |
| A B Electronics Inc | C10 | 2013 | Active |
| A B I Construction & Electric Inc | C10 + A, B | 1996 | Active |
| A C E Care Inc | C10 + B, C20 | 2004 | Active |
| A D R Security Systems Inc | C10 | 2011 | Active |
| A E HVAC & Electrical Inc | C10 + C20 | 2023 | Active |
| A N C Lighting Inc | C10 | 2024 | Active |
| A&J Technologies | C10 | 2025 | Active |
| Aba Electrical Services Inc | C10 | 2019 | Active |
| Abe Electric Inc | C10 | 2008 | Active |
| Abm Builder Corp | C10 + B, C36 | 2026 | Active |
| Above Electric Corp | C10 | 2023 | Active |
| Abp Electric Corp | C10 | 2018 | Active |
| AC Smart Homes LLC | C10 | 2026 | Active |
| Advance Building Protection Inc | C10 + C16 | 2014 | Active |
| Advanced Electrical Support Inc | C10 | 2024 | Active |
| Aecom Technical Services Inc | C10 + A, ASB, B +3 | 1992 | Active |
| Affordable Fire Services | C10 + C16, C20, C36 +1 | 2016 | Active |
| Aguilar Brother's Electrical Corp | C10 | 2023 | Active |
| Air Pro La Inc | C10 + C20, C38 | 2024 | Active |
| Alex & Alex Electrical Inc | C10 | 2020 | Active |
| Alfano Electric Incorporated | C10 | 2002 | Active |
| All Future Construction LLC | C10 + B, C20, C36 | 2005 | Active |
| All Pro Systems Inc | C10 | 2015 | Active |
| All Services Electrical Inc | C10 | 2021 | Active |
| Alpha Omega Builders | C10 + A, B | 2004 | Active |
| Amazing Airconditioning Inc | C10 + C20, C36, C46 | 2005 | Active |
| American Solar Power Inc | C10 + B, C39 | 2009 | Active |
| Amerimex Electric Inc | C10 | 2013 | Active |
| Amgreen Buiders Inc | C10 + B, C20, C36 | 2018 | Active |
| Amgreen Solar Electric | C10 + B, C20, C36 | 2013 | Active |
| Amgreen Solutions Inc | C10 + B, C20, C36 | 2010 | Active |
| Amos Electric Inc | C10 | 1997 | Active |
| Angel's Electrical Services Inc | C10 | 2021 | Active |
| Angeles Lighting Inc | C10 + B, C39 | 2008 | Active |
| Ankor Associates Inc | C10 + A, B, C20 +4 | 2014 | Active |
| Aphia Development & Construction Inc | C10 + B, C36 | 2018 | Active |
| Arco Electric Company Of Southern California Inc | C10 | 1980 | Active |
| Arguetas Electrical Inc | C10 | 2026 | Active |
| Athos Development & Investment Inc | C10 + B | 2018 | Active |
| Atlantic Builders Inc | C10 + B, C20, C36 | 2001 | Active |
| Atoz Electric Inc | C10 | 2016 | Active |
| Audio Command Systems | C10 | 1996 | Renew by Nov 30, 2026 |
| Aureus Electrical Solutions | C10 | 2026 | Active |
| Automated Fire Protection | C10 + C16 | 2011 | Active |
| Axiom Group | C10 + A, B, C21 +1 | 1999 | Active |
| Aztlan Electrical Contractors Inc | C10 | 2026 | Active |
| B & L Ruiz Builders Inc | C10 + B, C33 | 2010 | Active |
| B & S Construction Inc | C10 + B, C20, C33 +1 | 2004 | Active |
| B T K Electric Inc | C10 | 2023 | Active |
| Bateman Water Heating Engineering Inc | C10 + C4, C36, HAZ | 1992 | Active |
| Bear Contractors Inc | C10 + C16, C36 | 1994 | Active |
| Belair Design & Development Inc | C10 + B | 2023 | Active |
| BH Electric LLC | C10 | 2026 | Active |
| Big City Construction Inc | C10 + B | 2004 | Active |
| Bilt-Well Roof And Material Co | C10 + B, C20, C39 +1 | 1984 | Active |
| Blue Coast Inc | C10 + A, B, C27 +1 | 1991 | Renew by Dec 31, 2026 |
| Bonded Electric Construction Inc | C10 | 1983 | Active |
| Branover Contractors Inc | C10 + B | 1985 | Active |
| Brendon Davis Electric Incorporated | C10 | 2015 | Active |
| Brentwood Communications Incorporated | C10 + C7 | 1988 | Active |
| Bright City Electrical Inc | C10 | 2010 | Active |
| Bright Path Electric Inc | C10 | 2023 | Active |
| Bryden Electrical Inc | C10 | 1985 | Active |
| Build Space General Construction Inc | C10 + B | 2019 | Active |
| Builder 20 Inc | C10 + B | 2017 | Active |
| Building And Computer Electric Inc | C10 | 1976 | Active |
| Building Connection Inc | C10 + B | 2022 | Active |
| Buildla | C10 + B, C36 | 2007 | Active |
| Bustillo Electric Inc | C10 | 2019 | Active |
| C A L Electric | C10 | 1992 | Active |
| C C Construction Co Inc | C10 + A, B | 2007 | Active |
| C M V South Electric Inc | C10 | 2026 | Active |
| C T West Construction Inc | C10 + A, B | 2012 | Active |
| Cabrera Electric Inc | C10 | 2024 | Active |
| California Urban Electric | C10 | 2024 | Active |
| Caltron Construction Inc | C10 + A, B, C17 +3 | 1996 | Active |
| Cavanagh T W Electrical LLC | C10 | 2018 | Active |
| Cd-Ampers Inc | C10 | 2022 | Active |
| Cdy-Hvac Inc | C10 + C20 | 2018 | Renew by Dec 31, 2026 |
| Cedars Builders | C10 + B | 2017 | Active |
| China Pacific Inc | C10 + B, C20, C36 +2 | 1987 | Active |
| Choice Monitoring Corporation | C10 + C7 | 2024 | Active |
| Cia Electric | C10 | 1999 | Active |
| Citiwide Engineering Inc | C10 + A, B, C33 | 1991 | Active |
| Cle Electric Inc | C10 + A, B | 2008 | Renew by Dec 31, 2026 |
| Clickev LLC | C10 | 2024 | Active |
| Climate Care Electric LLC | C10 | 2026 | Active |
| Commscape Inc | C10 + B, C7, C27 | 2003 | Active |
| Comren Inc | C10 + B, C54 | 1993 | Active |
| Consolidated Security Industries Inc | C10 + C7 | 2019 | Active |
| Constant Solar Electric | C10 | 2001 | Active |
| Convention Electric Inc | C10 | 1998 | Active |
| Corvin Electric | C10 + B | 2025 | Active |