Apprenticeship Sponsor — page 6 of 20
5,826 businesses with an active “Apprenticeship Sponsor” credential — administered by the Department of Labor. State file of October 1, 2026.
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| Place | Business | Record | Credentials | Latest expiration |
|---|---|---|---|---|
| Washington Depot, CT | D.S.E. Security Systems LLC | 5075D35970 | Apprenticeship Sponsor | Jun 30, 2012 |
| Trumbull, CT | D.S.O. Mechanical Corporation | 4ED06975E3 | Apprenticeship Sponsor | Jun 30, 2027 |
| Simsbury, CT | D.W. BURR LANDSCAPE & DESIGN, INC. | B66FCAC3FD | Pesticide Application Business Registration + 2 more | Aug 31, 2027 |
| Old Saybrook, CT | D/E/F SERVICES GROUP LTD | 2F9A2EF7FE | Major Contractor + 4 more | Jun 30, 2027 |
| Southington, CT | DAC Electric | B51E64E797 | Apprenticeship Sponsor | Jun 30, 2004 |
| Bristol, CT | DACRUZ Manufacturing, Inc. | 43511047A9 | Apprenticeship Sponsor | Jun 30, 2027 |
| Thomaston, CT | Daddona Brothers Mechanical, LLC | A0EF006C39 | Apprenticeship Sponsor | Jun 30, 2019 |
| Watertown, CT | Daddona Electrical Services Inc. | CFEF599519 | Apprenticeship Sponsor | Jun 30, 2009 |
| Meriden, CT | Daffodil Plumbing LLC | 2C48D6091B | Apprenticeship Sponsor | Jun 30, 2026 |
| Meriden, CT | Dalco Electric, Inc. | 51E3731CA8 | Apprenticeship Sponsor | Jun 30, 2010 |
| Stamford, CT | Dale O. Duncan Inc. | 0B501CC459 | Apprenticeship Sponsor | Jun 30, 2027 |
| Shelton, CT | Dalling Heating & Air Conditioning | 3E234F1A3F | Apprenticeship Sponsor | Jun 30, 2027 |
| Putnam, CT | Dalmik Well Drilling | 0594E967CD | Apprenticeship Sponsor | Jun 30, 2010 |
| New London, CT | Dalux Cutz Barbershop LLC | 7EB50501BD | Apprenticeship Sponsor | Jun 30, 2026 |
| Higganum, CT | Damgud Plumbing, LLC | A45ADF3D29 | Apprenticeship Sponsor | Jun 30, 2012 |
| North Branford, CT | DAN BOYERS PLUMBING, LLC | 6189A7DE7B | Apprenticeship Sponsor | Jun 30, 2027 |
| East Hartford, CT | Dan Durrenberger Electrical Contractor | FA5C407854 | Apprenticeship Sponsor | Jun 30, 2004 |
| Putnam, CT | Dan Landry Electric, Inc. | A5ABA0AC63 | Apprenticeship Sponsor | Jun 30, 2005 |
| Meriden, CT | Dan Szymaszek & Sons Inc. | 69017582D6 | Apprenticeship Sponsor | Jun 30, 2007 |
| New London, CT | Dan Terry Plumbing LLC | B485427CF4 | Apprenticeship Sponsor | Jun 30, 2027 |
| Naugatuck, CT | Dan's Electric Service, LLC | 957D212834 | Apprenticeship Sponsor | Jun 30, 2006 |
| Rocky Hill, CT | Dana DePercio Electric Inc. | B05D284927 | Apprenticeship Sponsor | Jun 30, 2027 |
| Danbury, CT | Danbury Public Schools | 05CB0801F3 | Apprenticeship Sponsor | Jun 30, 2027 |
| Brookfield, CT | DANBURY WINAIR SHEET METAL | D566C8A2B8 | Apprenticeship Sponsor | Jun 30, 2027 |
| Windsor, CT | DANDELION ENERGY CORP. | C1DE6EBAD0 | Apprenticeship Sponsor | Jun 30, 2027 |
| Bristol, CT | Daneco Electric LLC | B4CE2C9E57 | Apprenticeship Sponsor | Jun 30, 2005 |
| Ridgefield, CT | Daniel J. McGinty Electric | 2AEF473237 | Apprenticeship Sponsor | Jun 30, 2009 |
| Burlington, CT | Daniel J. Symolon, LLC | 33224673C0 | Apprenticeship Sponsor | Jun 30, 2017 |
| Thompson, CT | Daniel Schmeelk Builder | 4D53D8E1DB | Apprenticeship Sponsor | Jun 30, 2011 |
| South Windsor, CT | Daniels Electric, Inc. | 8B37EBE0F6 | Apprenticeship Sponsor | Jun 30, 2017 |
| Portland, CT | DANIELS OIL CO | 30D151E7E5 | Home Heating Fuel Dealer + 3 more | Sep 30, 2027 |
| Brooklyn, CT | Danielson Glass Co | 354697269E | Apprenticeship Sponsor | Jun 30, 2027 |
| Cos Cob, CT | Dare Electric LLC | 89711C7CAB | Apprenticeship Sponsor | Jun 30, 2009 |
| Stamford, CT | Darien Air Systems, Inc. | 9469911647 | Apprenticeship Sponsor | Jun 30, 2019 |
| Darien, CT | Darien Electrical Contracting, Inc. | 9379EF1DE8 | Apprenticeship Sponsor | Jun 30, 2017 |
| Darien, CT | Darien Fuel Company, Inc. | CE1574F515 | Apprenticeship Sponsor | Jun 30, 2010 |
| Darien, CT | Darien Plumbing & Heating Inc. | DFA4241FF2 | Apprenticeship Sponsor | Jun 30, 2027 |
| Brooklyn, CT | Darrin's Electrical Services, LLC | DC7D1D3A8F | Apprenticeship Sponsor | Jun 30, 2016 |
| Wallingford, CT | DAT Contracting, LLC | 71E9F24A6D | Apprenticeship Sponsor | Jun 30, 2017 |
| Easton, CT | DAT Electrical Inc | 4AE51B072D | Apprenticeship Sponsor | Jun 30, 2027 |
| Bridgeport, CT | Data Tel L.L.C. | B078E37309 | Apprenticeship Sponsor | Jun 30, 2027 |
| South Meriden, CT | Data-Link Corporation | F9CA0358F2 | Apprenticeship Sponsor | Jun 30, 2027 |
| Falls Village, CT | Dave Kowalski, LLC | D9B9615A85 | Apprenticeship Sponsor | Jun 30, 2018 |
| Monroe, CT | Dave Verrilli Electric LLC | 4DC0428D29 | Apprenticeship Sponsor | Jun 30, 2017 |
| Danbury, CT | Dave's Barbershop | 97991A5DEC | Apprenticeship Sponsor | Jun 30, 2025 |
| Weston, CT | Davenport Electric Co., Inc. | B030E1ACBC | Apprenticeship Sponsor | Jun 30, 2027 |
| Norwalk, CT | David Diescher Plumbing | 4765089E8D | Apprenticeship Sponsor | Jun 30, 2008 |
| Pomfret Center, CT | David Electric Inc. | 60849CAC1C | Apprenticeship Sponsor | Jun 30, 2027 |
| Fairfield, CT | David Gasso Electrical Services | A90803DB66 | Apprenticeship Sponsor | Jun 30, 2020 |
| Goshen, CT | David Harmon Plumbing & Heating | 3F265DB075 | Apprenticeship Sponsor | Jun 30, 2017 |
| Great Barrington, MA | David L. Ralph Electrician, LLC | 9F62B678CA | Apprenticeship Sponsor | Jun 30, 2008 |
| Westerly, RI | David Lennon Electric | 66087F7F76 | Apprenticeship Sponsor | Jun 30, 2013 |
| Agawam, MA | David R. Northup Electrical Contractors, Inc. | 68441EBDBB | Apprenticeship Sponsor | Jun 30, 2027 |
| Brookfield, CT | David Sousa Plumbing & Heating Co., LLC | 52740FA151 | Apprenticeship Sponsor | Jun 30, 2026 |
| Lebanon, CT | Davidson Electric, LLC | 6D9CED0F7F | Apprenticeship Sponsor | Jun 30, 2027 |
| Somers, CT | Davidson Plumbing, Heating & Remodeling, LLC | 67731873BD | Apprenticeship Sponsor | Jun 30, 2008 |
| Derby, CT | Davis Oil Company | 04EC17CF4C | Apprenticeship Sponsor | Jun 30, 2011 |
| Trumbull, CT | Davis Plumbing & Heating | 5371C4A614 | Apprenticeship Sponsor | Jun 30, 2023 |
| Broad Brook, CT | Davy's Plumbing, LLC | BCB29936ED | Apprenticeship Sponsor | — |
| North Branford, CT | Dawson Electric, LLC | 9F02620F4D | Apprenticeship Sponsor | Jun 30, 2027 |
| Broad Brook, CT | Day and Night Services LLC | 50449BB1E9 | Apprenticeship Sponsor | Jun 30, 2026 |
| Putnam, CT | DAY KIMBALL HEALTHCARE FACILITIES DEPARTMENT | 277297E4A4 | Apprenticeship Sponsor | Jun 30, 2027 |
| Torrington, CT | Day Plumbing & Heating Co Inc | B585FD1280 | Apprenticeship Sponsor | Jun 30, 2027 |
| Oakdale, CT | DB LUNT ELECTRICAL CONTRACTORS LLC | 1023666DA7 | Apprenticeship Sponsor + 1 more | Jun 30, 2027 |
| Enfield, CT | DBA Miller Oil Company | 54BC2AC1BD | Apprenticeship Sponsor | Jun 30, 2027 |
| Cromwell, CT | DBS Energy Incorporated | AF3D95314F | Apprenticeship Sponsor | Jun 30, 2017 |
| Hamden, CT | DC Electric Company, Inc. | 41E8F7D7E6 | Apprenticeship Sponsor | Jun 30, 2010 |
| Yantic, CT | DC Sheetmetal, LLC | B4788ED53A | Apprenticeship Sponsor | Jun 30, 2027 |
| Danielson, CT | DCC PROPANE, LLC/DBA SAVEWAY PETROLEUM | A03CE6EE99 | Apprenticeship Sponsor | Jun 30, 2026 |
| Tolland, CT | DCG Electric LLC | 1BDCE106E4 | Apprenticeship Sponsor | Jun 30, 2006 |
| Goshen, CT | DCR Plumbing, LLC | 582483D409 | Apprenticeship Sponsor | Jun 30, 2027 |
| Manchester, CT | DDB Plumbing & Drain Cleaning, LLC | 252EEDF2AB | Apprenticeship Sponsor | Jun 30, 2017 |
| Middlebury, CT | DDM Mechanical | 489957D116 | Apprenticeship Sponsor | Jun 30, 2027 |
| South Windsor, CT | DDS LEGACY GROUP Inc | 086AB3D2C1 | Apprenticeship Sponsor | Jun 30, 2028 |
| Morris, CT | DEACON EXCAVATING LLC | 262E74EDAD | Apprenticeship Sponsor + 1 more | Jun 30, 2027 |
| New Milford, CT | Deak Electric, Inc. | F9BBE9199A | Apprenticeship Sponsor + 1 more | Jun 30, 2027 |
| Naugatuck, CT | Dean Custom Awnings of CT, LLC | 340AD12CDD | Apprenticeship Sponsor | Jun 30, 2021 |
| Putnam, CT | Deary Electric & Renovations, LLC | 5AC4A27273 | Apprenticeship Sponsor | Jun 30, 2024 |
| Bethel, CT | Decca Electric LLC | 12FC86BB27 | Apprenticeship Sponsor | Jun 30, 2010 |
| Canaan, CT | Decker & Beebe, Inc. | 7C2347F515 | Apprenticeship Sponsor | Jun 30, 2027 |
| North Haven, CT | DECOLA'S PLUMBING & HEATING INC | A6702044F3 | Home Improvement Contractor + 1 more | Mar 31, 2027 |
| Portland, CT | Dedicated Electric LLC | C5D2AF099A | Apprenticeship Sponsor | Jun 30, 2027 |
| Windsor Locks, CT | Dedicated Plumbing & Drain, LLC | 6FB355FB14 | Apprenticeship Sponsor | Jun 30, 2025 |
| Woodstock, CT | Deep 6 Plumbing & Heating | D1CCCD91D6 | Apprenticeship Sponsor | Jun 30, 2024 |
| Deep River, CT | Deep River Oil Co.,Inc. | 591FF1E596 | Apprenticeship Sponsor | Jun 30, 2008 |
| Waterford, CT | Deer Electric, LLC | DA51C29CE9 | Apprenticeship Sponsor | Jun 30, 2027 |
| Stamford, CT | DEFCO Glass, LLC | 8ECD04A466 | Apprenticeship Sponsor | Jun 30, 2018 |
| North Haven, CT | DeFilippo Electric, LLC | 18BDC4BB56 | Apprenticeship Sponsor | Jun 30, 2024 |
| Darien, CT | DeForest Electrical Contracting, LLC | DC70FD9937 | Apprenticeship Sponsor | Jun 30, 2027 |
| West Simsbury, CT | DEGREE HEATING A/C & MECHANICAL SERVICE | 6C7DC28833 | Apprenticeship Sponsor | Jun 30, 2017 |
| Hartford, CT | DEITCH ENERGY | 4A31577081 | Home Heating Fuel Dealer + 2 more | Sep 30, 2027 |
| South Windsor, CT | Delco Air, Inc. | 8DDDC1ADBD | Apprenticeship Sponsor | Jun 30, 2010 |
| Broad Brook, CT | DelConte Electric | 6B19921E6E | Apprenticeship Sponsor | Jun 30, 2007 |
| Wallingford, CT | DelGreco Electric, LLC | 1E401EF5D9 | Apprenticeship Sponsor | Jun 30, 2022 |
| Somers, CT | DelGreco Enterprises LLC | 17B3D81603 | Apprenticeship Sponsor | Jun 30, 2015 |
| Preston, CT | Delia Mechanical Plumbing & Heat/ LLC | E8FBED7984 | Apprenticeship Sponsor | Jun 30, 2016 |
| Watertown, CT | Delmar Electrical Contractors LLC | D3C64C7CB2 | Apprenticeship Sponsor | Jun 30, 2027 |
| Monroe, CT | DelMastro Plumbing & Heating | F919745F5D | Apprenticeship Sponsor | Jun 30, 2005 |
| Glastonbury, CT | Delponte Plumbing & Heating, LLC | 830BB5D900 | Apprenticeship Sponsor + 1 more | Jun 30, 2027 |
| Prospect, CT | Delson Plumbing & Heating Inc. | B7A56C3735 | Apprenticeship Sponsor | Jun 30, 2016 |
| Greenwich, CT | Delta Plumbing & Heating, LLC | C19D2FF999 | Apprenticeship Sponsor | Jun 30, 2005 |
| Hamden, CT | Delta Tool and Mold, LLC | A6F25980D8 | Apprenticeship Sponsor | Jun 30, 2017 |
| Waterbury, CT | Delta-Wye Electric Construction Co. | 544E798E6D | Apprenticeship Sponsor | Jun 30, 2006 |
| North Haven, CT | DELUCIA FUEL OIL CO LLC | DF43CF7660 | Home Heating Fuel Dealer + 2 more | Sep 30, 2027 |
| Portland, CT | DeMaio Plumbing & Heating | C0C29E28B6 | Apprenticeship Sponsor | Jun 30, 2011 |
| Danielson, CT | DeMarco Plumbing Company | 328493477C | Apprenticeship Sponsor | Jun 30, 2027 |
| Stamford, CT | DeMartino Electric LLC | 30AD565023 | Apprenticeship Sponsor | Jun 30, 2027 |
| Suffield, CT | Deming Electric, LLC | B9B57EC43B | Apprenticeship Sponsor | Jun 30, 2027 |
| Watertown, CT | DEMSEY MANUFACTURING COMPANY, INC. | 1031ABB7BE | Apprenticeship Sponsor | Jun 30, 2027 |
| Durham, CT | DeNicola Plumbing LLC | 0CF231AB6C | Apprenticeship Sponsor | Jun 30, 2027 |
| Windham, CT | Denis Electric | 51CAFD84EF | Apprenticeship Sponsor | Jun 30, 2004 |
| East Lyme, CT | Dennis F. Sheehan, Jr. & Sons Plumbing & Heating Contractor | 9C8E2CE8FA | Apprenticeship Sponsor | Jun 30, 2012 |
| Unionville, CT | Dennis Guerard Electric Co. | C6D5630285 | Apprenticeship Sponsor | Jun 30, 2012 |
| Stonington, CT | DENSMORE OIL INC | 879474E51D | Motor Fuel Quality Registration + 4 more | Oct 31, 2027 |
| Hartford, CT | Department of Public Works | 4F20E15D03 | Apprenticeship Sponsor | Jun 30, 2009 |
| Plainville, CT | DEPCO MECHANICAL LLC | A1103047A8 | Home Improvement Contractor + 1 more | Mar 31, 2027 |
| Prospect, CT | DEPENDABLE ENERGY | DB26F4614C | Home Heating Fuel Dealer + 2 more | Sep 30, 2027 |
| North Branford, CT | Dependable Heating & Cooling, LLC | CA0FCE7E95 | Apprenticeship Sponsor | Jun 30, 2024 |
| North Branford, CT | Dependable Repair, Inc. | 6A50F436F2 | Apprenticeship Sponsor | Jun 30, 2025 |
| North Franklin, CT | Depot Pump & Supply, LLC | 4F0E64484E | Apprenticeship Sponsor | Jun 30, 2017 |
| Darien, CT | Derek Electric, LLC | 65465E8A21 | Apprenticeship Sponsor | Jun 30, 2023 |
| Bloomfield, CT | Deringer-Ney Inc. | 504C030634 | Apprenticeship Sponsor | Jun 30, 2027 |
| Stratford, CT | DeRosa Electric L.L.C. | 762D16E1C4 | Apprenticeship Sponsor | Jun 30, 2011 |
| Norwich, CT | DeRosier Electric Inc. | 2279EE057A | Apprenticeship Sponsor | Jun 30, 2026 |
| New Haven, CT | Design Electric | DA64CC1D0B | Apprenticeship Sponsor | Jun 30, 2014 |
| Plainville, CT | Design Electrical Contractors, LLC | 1AEE50C09B | Apprenticeship Sponsor | Jun 30, 2009 |
| Wallingford, CT | Desjardins Electric, LLC | 619473381F | Apprenticeship Sponsor | Jun 30, 2027 |
| Shelton, CT | DEUS ZAFE HOLDINGS INC BENJAMIN FRANKLIN PLUMBING | 5C15C3B324 | Apprenticeship Sponsor + 1 more | Jun 30, 2027 |
| Norwalk, CT | DEVINE BROTHERS, INC. | 591C65A9C2 | Apprenticeship Sponsor | Jun 30, 2027 |
| Hingham, MA | DEVLIN CONTRACTING AND MAINTENANCE INC | 2EDCD3B5D8 | Home Improvement Contractor + 1 more | Mar 31, 2027 |
| Wolcott, CT | Devon Precision Industries | 55B05E5260 | Apprenticeship Sponsor | Jun 30, 2014 |
| Stratford, CT | DGJ Elect. & Home Improvemnt Cont., LLC | F2DA2D12C9 | Apprenticeship Sponsor | Jun 30, 2027 |
| Hamden, CT | DHL Electrical Services, LLC | CF0D617D78 | Apprenticeship Sponsor | Jun 30, 2016 |
| Madison, CT | DHM Electrical Services, LLC | 4A27201638 | Apprenticeship Sponsor | Jun 30, 2027 |
| Waterbury, CT | DHR Precision Products, Inc. | 063D5E17C7 | Apprenticeship Sponsor | — |
| Ansonia, CT | Di Iulio Electric LLC | 4591946C10 | Apprenticeship Sponsor | Jun 30, 2009 |
| New Haven, CT | Di Rienzo Mechanical Contractors, Inc. | DEDAA281F9 | Apprenticeship Sponsor | Jun 30, 2026 |
| Preston, CT | Diakonea Insulation | EB920FF688 | Apprenticeship Sponsor | Jun 30, 2012 |
| Danbury, CT | Diba Industries, Inc. | 3F65292930 | Apprenticeship Sponsor | Jun 30, 2020 |
| Woodbury, CT | Dictograph Security Systems | 8C7C060786 | Apprenticeship Sponsor | Jun 30, 2004 |
| Middletown, CT | DIDATO'S OIL SERVICE | CBCD047155 | Home Heating Fuel Dealer + 1 more | Sep 30, 2027 |
| Manchester, CT | Diebold, Inc. | 9B855C2881 | Apprenticeship Sponsor | Jun 30, 2016 |
| Woodbury, NY | Digital Labor Solutions | 8A2D0BCFDE | Apprenticeship Sponsor | Jun 30, 2026 |
| Lyme, CT | Dill's Electric, Inc. | 33D4EF66D6 | Apprenticeship Sponsor | Jun 30, 2022 |
| Southbury, CT | Dilley Electric, LLC | 21174426F7 | Apprenticeship Sponsor | Jun 30, 2013 |
| Sherman, CT | DiMaggio Plumbing & Heating, Inc. | 34ECF6B05E | Apprenticeship Sponsor | Jun 30, 2027 |
| Johnston, RI | DIMEO CONSTRUCTION COMPANY | A6F3F2F7D3 | Major Contractor + 1 more | Jun 30, 2027 |
| Stamford, CT | Dinos Oil Company | DC2FF9EB18 | Apprenticeship Sponsor | Jun 30, 2005 |
| Westerly, RI | Dinwoodie Plumbing and Heating | 45F80D1807 | Apprenticeship Sponsor | Jun 30, 2005 |
| Bloomfield, CT | DIRECT ELECTRICAL SERVICES, LLC | 844B19FC29 | Apprenticeship Sponsor | Jun 30, 2022 |
| Middletown, CT | Direct Energy Solar | 718FC0AA01 | Apprenticeship Sponsor | Jun 30, 2018 |
| Durham, CT | DIRECT HOME SERVICES | 40AE706915 | Apprenticeship Sponsor | Jun 30, 2026 |
| Greenwich, CT | Diverse Communications Inc., LLC | 5CB971E120 | Apprenticeship Sponsor | Jun 30, 2012 |
| Plantsville, CT | Diverse Electrical Contractors, LLC | 8589322A1B | Apprenticeship Sponsor | Jun 30, 2022 |
| North Branford, CT | Diversified | 5A7EE4CF21 | Apprenticeship Sponsor | Jun 30, 2023 |
| Bridgeport, CT | Diversified Electrical Contractors | DBEE722886 | Apprenticeship Sponsor | Jun 30, 2016 |
| South Windsor, CT | Diversified Electrical Systems, Inc. | 05D2011323 | Apprenticeship Sponsor | Jun 30, 2007 |
| Cheshire, CT | Diversity Construction Group, LLC | A7B3797128 | Apprenticeship Sponsor | Jun 30, 2016 |
| Shelton, CT | DJ Melodia Plumbing & Heating | CEEA79DE9F | Apprenticeship Sponsor | Jun 30, 2027 |
| Guilford, CT | DJ Russo Services | 18B7AEEC06 | Apprenticeship Sponsor | Jun 30, 2022 |
| Ellington, CT | DLC Electric Services, LLC | 7259F8A0E3 | Apprenticeship Sponsor | Jun 30, 2019 |
| Middletown, CT | DMA Electric, LLC | 37A431E9AB | Apprenticeship Sponsor | Jun 30, 2027 |
| West Suffield, CT | DMC Unlimited, LLC | 1036EC1BC9 | Apprenticeship Sponsor | Jun 30, 2027 |
| Naugatuck, CT | DMF Electric, LLC | 5F4C977B47 | Apprenticeship Sponsor | Jun 30, 2015 |
| Wolcott, CT | DNA Mechanical Services LLC | 3BB3AD0277 | Apprenticeship Sponsor | Jun 30, 2027 |
| Andover, CT | DNA Plumbing | 3331593C13 | Apprenticeship Sponsor | Jun 30, 2017 |
| Ansonia, CT | DOC Service, LLC | 39BDE77D12 | Apprenticeship Sponsor | Jun 30, 2027 |
| Norwich, CT | Doc's Plumbing, LLC | 3AA3334FFF | Apprenticeship Sponsor | Jun 30, 2011 |
| Brookfield, CT | Doctor Electric Inc. | D6167125F9 | Apprenticeship Sponsor | Jun 30, 2021 |
| South Norwalk, CT | Dominick Fuel Inc. | B8C042A555 | Apprenticeship Sponsor | Jun 30, 2022 |
| Waterford, CT | DOMINION NUCLEAR CONNECTICUT | 405E87F8CA | First Responder + 1 more | Sep 30, 2027 |
| Old Saybrook, CT | DON MORRISON INC | A78F5EB9EC | Home Improvement Contractor + 1 more | Mar 31, 2027 |
| Danbury, CT | Don Paul Mechanical, LLC | D6C2B58B38 | Apprenticeship Sponsor | Jun 30, 2011 |
| Ellington, CT | DON'S HEATING & COOLING SOLUTIONS LLC | 5D994CC799 | Apprenticeship Sponsor | Jun 30, 2027 |
| South Windsor, CT | Don-Co Electric, LLC | F4EB5A0D67 | Apprenticeship Sponsor | Jun 30, 2009 |
| Hampton, CT | Donahue General Contractors, Inc. | 384171883C | Apprenticeship Sponsor + 2 more | Jun 30, 2027 |
| Plantsville, CT | DONALD SULLIVAN & SONS LLC | 94AF7CDD02 | Apprenticeship Sponsor | Jun 30, 2027 |
| Groton, CT | Doncasters Precision Castings - New England | C03E5C5CFD | Apprenticeship Sponsor | Jun 30, 2015 |
| Newington, CT | Done Construction LLC | 4B7663D785 | Apprenticeship Sponsor | Jun 30, 2012 |
| Marlborough, CT | Done Right Plumbing Services, LLC | D22D5BB845 | Apprenticeship Sponsor | Jun 30, 2027 |
| Monroe, CT | Done-Rite Contracting, LLC | 495088AB06 | Apprenticeship Sponsor | Jun 30, 2009 |
| Newtown, CT | Donnelly Heating & A/C Maintenance Inc. | C31390D246 | Apprenticeship Sponsor + 1 more | Jun 30, 2027 |
| Brookfield, CT | Donnelly Security | 6B8B0BD701 | Apprenticeship Sponsor | Jun 30, 2027 |
| South Windsor, CT | Doosan Fuel Cell America | 1F4067EFDE | Apprenticeship Sponsor | Jun 30, 2026 |
| Trumbull, CT | Dorans Plumbing and Heating | A5A454F8F7 | Apprenticeship Sponsor | Jun 30, 2016 |
| Branford, CT | Dougherty Oil Company, Inc. | ABE9C5ED05 | Apprenticeship Sponsor | Jun 30, 2014 |
| New Milford, CT | Douglas C. Kenley Plumbing, Heating & A/C | E954315733 | Apprenticeship Sponsor | Jun 30, 2005 |
| Berlin, CT | DOUGLAS MECHANICAL SERVICES | 23E42D68AC | Apprenticeship Sponsor + 1 more | Jun 30, 2027 |
| Farmington, CT | Douglas Plumbing, Heating & Air Conditioning | 8263F8C95E | Apprenticeship Sponsor | Jun 30, 2027 |
| Somers, CT | Douglas White electrical Services | 9AAF09F2F4 | Apprenticeship Sponsor | — |
| East Haven, CT | Dowd Electric | 77E0EC021E | Apprenticeship Sponsor | Jun 30, 2017 |
| Danbury, CT | Doyle Electric LLC | EA5B4E83CB | Apprenticeship Sponsor | Jun 30, 2019 |
| New Milford, CT | DP Electrical Contracting, LLC | E4402FC086 | Apprenticeship Sponsor | Jun 30, 2011 |
| Milford, CT | DPC Quality Pump Service | E29E222766 | Apprenticeship Sponsor | Jun 30, 2021 |
| Norwich, CT | DPO NUTMEG LLC | 3E285CF1D1 | Apprenticeship Sponsor | Jun 30, 2027 |
| Seymour, CT | Dr. Energy Saver CT, LLC | 022D90D4D5 | Apprenticeship Sponsor | Jun 30, 2015 |
| Trumbull, CT | Drain King, LLC | 5A15138570 | Apprenticeship Sponsor + 1 more | Jun 30, 2027 |
| Danbury, CT | Drain Surgeon Plumbing & Heating, LLC | DAD27CB015 | Apprenticeship Sponsor | Jun 30, 2022 |
| Hamden, CT | Drain Wizard Plumbing LLC | F599E55B41 | Apprenticeship Sponsor + 1 more | Jun 30, 2027 |
| Colchester, CT | DRAINWORKS PLUMBING & SEPTIC LLC | 4D7BABC962 | Home Improvement Contractor + 1 more | Mar 31, 2027 |
| Chaplin, CT | DRC Electric, LLC | F3F10A7FE5 | Apprenticeship Sponsor | Jun 30, 2027 |
| Wethersfield, CT | Dream Barbershop | F32A1BF0F6 | Apprenticeship Sponsor | Jun 30, 2027 |
| Wallingford, CT | Dreissen Electric Company, Inc. | B4018857DF | Apprenticeship Sponsor | Jun 30, 2013 |
| Trumbull, CT | Drew Plumbing | A955090662 | Apprenticeship Sponsor | Jun 30, 2009 |
| Winsted, CT | DRT Aerospace, LLC | BC8CCAADA5 | Apprenticeship Sponsor | Jun 30, 2027 |
| Coventry, CT | DS Comfort Control LLC | 4C2B872F25 | Apprenticeship Sponsor | Jun 30, 2027 |
| Dayville, CT | DSM, Inc. | 8F6500B949 | Apprenticeship Sponsor | Jun 30, 2009 |
| Manchester, CT | DuBaldo Electric, LLC | 75012DB195 | Apprenticeship Sponsor | Jun 30, 2008 |
| Manchester, CT | DuBaldo Security Systems, Inc. | BA97153E03 | Apprenticeship Sponsor | Jun 30, 2027 |
| Farmington, CT | Ducci Electric | D8B2C7A4E9 | Apprenticeship Sponsor | — |
| Milford, CT | Duct Diagnostics | 9C5A5FF5A1 | Apprenticeship Sponsor + 1 more | Jun 30, 2028 |
| Windsor, CT | Duct Works, LLC | 18EE737136 | Apprenticeship Sponsor | Jun 30, 2007 |
| Hamden, CT | Duct Worx Unlimited, LLC | F095B95318 | Apprenticeship Sponsor | Jun 30, 2014 |
| Bloomfield, CT | Ductco, LLC | 0529A512FE | Apprenticeship Sponsor | Jun 30, 2027 |
| Southington, CT | DUCTWORKS HVAC SERVICES, LLC | C9B9ED4B5D | Apprenticeship Sponsor | Jun 30, 2027 |
| Glastonbury, CT | Dufford Construction Company | C01BAE0CB7 | Apprenticeship Sponsor | Jun 30, 2009 |
| Westport, CT | Duffy Plumbing | 3837784AA7 | Apprenticeship Sponsor | Jun 30, 2022 |
| Manchester, CT | Dumas Electric Company | 511303C5DB | Apprenticeship Sponsor | Jun 30, 2008 |
| Norwalk, CT | Duncan & Duncan Plumbing | 33CF67D531 | Apprenticeship Sponsor | Jun 30, 2007 |
| Westbrook, CT | Duncan Downie's Excavation, Inc. | C06BE9958B | Apprenticeship Sponsor | Jun 30, 2015 |
| Stonington, CT | Duncklee, Inc. | CD4AB49A0B | Apprenticeship Sponsor | Jun 30, 2027 |
| Westbrook, CT | Dunham Plumbing and Heating | 56268243F5 | Apprenticeship Sponsor | Jun 30, 2024 |
| Voluntown, CT | Dunrite Plumbing & Heating LLC | 4452C77AFB | Apprenticeship Sponsor | Jun 30, 2009 |
| Waterbury, CT | Durable Radiator & Auto Body Inc. | 4F19720534 | Apprenticeship Sponsor | Jun 30, 2009 |
| Durham, CT | Durham Manufacturing Co. | 13B0438A35 | Apprenticeship Sponsor | Jun 30, 2022 |
| East Longmeadow, MA | DUTC Systems | A0681B66A7 | Apprenticeship Sponsor | Jun 30, 2019 |
| Moodus, CT | DUTCH OIL COMPANY INC | D6EAAABA8A | Home Heating Fuel Dealer + 2 more | Sep 30, 2027 |
| East Lyme, CT | DWB Electrical Services, LLC | 38E9195A31 | Apprenticeship Sponsor | Jun 30, 2024 |
| Torrington, CT | Dymax Corporation | 422F624D3B | Apprenticeship Sponsor | Jun 30, 2022 |
| Ellington, CT | Dymotek Corp. | 55B94841EB | Apprenticeship Sponsor | Jun 30, 2020 |
| Manchester, CT | Dyna Electric, Inc. | 3DEBE6F3EF | Apprenticeship Sponsor | Jun 30, 2027 |
| Tolland, CT | Dynamark Security | 6A655B91E4 | Apprenticeship Sponsor | Jun 30, 2019 |
| Bloomfield, CT | Dynamic Electrical Contractor, Inc. | AC9994E5ED | Apprenticeship Sponsor | Jun 30, 2018 |
| Meriden, CT | Dynamic Electrical Systems, LLC | 4B5D8CB88D | Apprenticeship Sponsor | Jun 30, 2027 |
| Plainville, CT | Dynamic Mechanical Plumbing, Heating & AC | AEF19A451E | Apprenticeship Sponsor | Jun 30, 2027 |
| Milldale, CT | Dynamic Security Systems, Inc. dba Maximum Sound & Security | 10E1C0C2BE | Apprenticeship Sponsor | Jun 30, 2027 |
| Watertown, CT | Dynamo LLC | 83318979B1 | Apprenticeship Sponsor | Jun 30, 2027 |
| New London, CT | DYNASTY BARBER LOUNGE LLC | 8206A2B2E2 | Apprenticeship Sponsor | Jun 30, 2027 |
| Simsbury, CT | Dyno Nobel, Inc. | 83D03E0B64 | Apprenticeship Sponsor | Jun 30, 2027 |
| Norwich, CT | Dziengiel's Plumbing Unlimited LLC | D5FCC4B328 | Apprenticeship Sponsor | Jun 30, 2008 |
| Woodbury, CT | E & E Electric, LLC | C66185ABBA | Apprenticeship Sponsor | Jun 30, 2013 |
| Winsted, CT | E & E Tool & Mfg. Co., Inc. | AC55F35957 | Apprenticeship Sponsor | Jun 30, 2027 |
| Trumbull, CT | E & J Comfort Systems, LLC | E0EEB0ABF8 | Apprenticeship Sponsor + 1 more | Jun 30, 2027 |
| Fairfield, CT | E & L Plumbing, LLC | 247F3E5178 | Apprenticeship Sponsor | Jun 30, 2024 |
| West Haven, CT | E & M Barbershop and Salon | A95A5803C4 | Apprenticeship Sponsor | Jun 30, 2027 |
| Tolland, CT | E & S Gage Inc. | 584D1737C0 | Apprenticeship Sponsor | Jun 30, 2009 |
| Naugatuck, CT | E 1 Electric, LLC | E527210E0E | Apprenticeship Sponsor | Jun 30, 2010 |
| Norwalk, CT | E and A Electric, LLC | 1C821A98D2 | Apprenticeship Sponsor | Jun 30, 2027 |
| Bridgeport, CT | E L WAGNER CO INC | 3848564E4D | Home Improvement Contractor + 1 more | Mar 31, 2027 |
| Middlefield, CT | E-Muscle, LLC. | 3E622F3052 | Apprenticeship Sponsor | Jun 30, 2013 |
| Cheshire, CT | E-N-E Irrigation Contractors, LLC | 92171B60D9 | Apprenticeship Sponsor | Jun 30, 2018 |
| Danbury, CT | E-PRO Electrical Services, LLC | D434FA7E3E | Apprenticeship Sponsor | Jun 30, 2009 |
| Andover, CT | E-Tech Systems LLC | FCF7312A70 | Apprenticeship Sponsor | Jun 30, 2027 |
| Manchester, CT | E-Z OIL COMPANY INC | CF35613660 | Home Heating Fuel Dealer + 2 more | Sep 30, 2027 |
| Hamden, CT | E-Z Service & Maintenance Contractors, LLC | 107A3D4E3B | Apprenticeship Sponsor | Jun 30, 2019 |
| Danbury, CT | E. DeBrito Company, Inc. | 8E57064DA7 | Apprenticeship Sponsor | Jun 30, 2005 |
| New Preston, CT | E. Garrity Water Solutions, LLC | C1A837D366 | Apprenticeship Sponsor | Jun 30, 2024 |
| Meriden, CT | E. Haberli Electric LLC | 96F0085183 | Apprenticeship Sponsor | Jun 30, 2027 |
| Terryville, CT | E.C.P. Mechanical LLC | 9200064223 | Apprenticeship Sponsor | Jun 30, 2021 |
| Southington, CT | E.D.P. Wiring Systems LLC | B46BD3C521 | Apprenticeship Sponsor | Jun 30, 2022 |
| Putnam, CT | E.D.S. Mechanical Inc. | 98E39490B1 | Apprenticeship Sponsor | Jun 30, 2027 |
| North Haven, CT | E.J.S. Electric, LLC | 3F0373A5FD | Apprenticeship Sponsor | Jun 30, 2007 |
| Wallingford, CT | E.N.T. Heating & Cooling Co., Inc. | 17BEF0AD39 | Apprenticeship Sponsor | Jun 30, 2018 |
| West Haven, CT | E.T.C. ELECTRICAL CONTRACTORS, LLC | 7DCDC3315A | Apprenticeship Sponsor | Jun 30, 2027 |
| Middletown, CT | E.U. Electric Unlimited Inc. | FE07BBFE20 | Apprenticeship Sponsor | Jun 30, 2007 |
| Washington Depot, CT | Eagle Electric Services LLC | 9C07DBAD5A | Apprenticeship Sponsor | Jun 30, 2027 |
| Waterford, CT | Eagle Electrical Services, LLC | 5975F5F8BA | Apprenticeship Sponsor | Jun 30, 2026 |
| Oakville, CT | Eagle Eye Security, LLC | F1CA195D0A | Apprenticeship Sponsor | Jun 30, 2026 |
| Westerly, RI | Eagle Industries Inc. | A98670583C | Apprenticeship Sponsor | Jun 30, 2016 |
| Killingworth, CT | Earley Detection Systems, LLC | DAB95F8F29 | Apprenticeship Sponsor | Jun 30, 2025 |
| Kensington, CT | Earth Contractors, LLC | 0E6EACB165 | Apprenticeship Sponsor + 1 more | Jun 30, 2027 |
| Prospect, CT | EARTH CORE ENERGY SERVICES LLC | 753372463A | Major Contractor + 1 more | Jun 30, 2027 |
| Rocky Hill, CT | EARTH SMART SOLAR LLC | F70307BED7 | Home Improvement Contractor + 1 more | Mar 31, 2027 |
| Ellington, CT | Earthlight Technologies, LLC | FF16490787 | Apprenticeship Sponsor + 1 more | Jun 30, 2027 |
| New Milford, CT | East Branch Engineering & Manufacturing, Inc. | B86A3F922E | Apprenticeship Sponsor | Jun 30, 2017 |
| Stamford, CT | EAST COAST ELECTRIC | 86DFC6E141 | Apprenticeship Sponsor | Jun 30, 2027 |
| Mystic, CT | East Coast Electrical LLC | 349F049676 | Apprenticeship Sponsor | Jun 30, 2025 |
| Seymour, CT | East Coast Heating & Cooling LLC | 000B3BF63B | Apprenticeship Sponsor | Jun 30, 2008 |
| Norwalk, CT | East Coast Irrigation, LLC | 017DC31310 | Apprenticeship Sponsor | Jun 30, 2014 |
| Cheshire, CT | East Coast Mechanical Inc. | ADB264A4B2 | Apprenticeship Sponsor | Jun 30, 2027 |
| Milford, CT | EAST COAST PLUMBING & DRAIN CLEANING, INC. | 2811196DE8 | Apprenticeship Sponsor | Jun 30, 2025 |
| Clinton, CT | East Coast Security Services, Inc. | 340CFD84A7 | Apprenticeship Sponsor | Jun 30, 2009 |
| Westbrook, CT | East Coast Security Services, Inc. | 3E98D59DB1 | Apprenticeship Sponsor | Jun 30, 2005 |
| Litchfield, CT | East Coast Sheet Metal LLC | 0B61864977 | Apprenticeship Sponsor | Jun 30, 2027 |
| Manorville, NY | East End Fire, Inc. | F1BD2AB756 | Apprenticeship Sponsor | Jun 30, 2027 |
| South Windsor, CT | East Hartford Electrical | EF890D897E | Apprenticeship Sponsor | Jun 30, 2019 |
| East Hartford, CT | East Hartford Heating & Cooling LLC | D9B5E5756C | Apprenticeship Sponsor | Jun 30, 2026 |
| East Haven, CT | East Haven Board of Education | D002017FD1 | Apprenticeship Sponsor | Jun 30, 2026 |
| Guilford, CT | EAST RIVER ENERGY | A1A550693B | Motor Fuel Quality Registration + 3 more | Oct 31, 2027 |
| New Haven, CT | EAST SHORE GLASS INC GLASS, GLAZING & HOME IMPROVEMENT | 811ABC7DD2 | Home Improvement Contractor + 1 more | Mar 31, 2027 |
| New Haven, CT | East West Mechanical, LLC | 95A96CD113 | Apprenticeship Sponsor | Jun 30, 2023 |
| Hampton, CT | EASTCONN REGIONAL EDUCATIONAL SERVICE CENTER INCORPORATED | D50123A5E1 | Apprenticeship Sponsor + 1 more | Jun 30, 2027 |
| Burlington, CT | Eastern Boiler Repair Inc. | F30A27CB03 | Apprenticeship Sponsor | Jun 30, 2019 |
| Norwich, CT | EASTERN CONN. HEATING COMPANY | 2424D99809 | Apprenticeship Sponsor | Jun 30, 2027 |
| Old Lyme, CT | Eastern CT Solar LLC | 2CC331DDF1 | Apprenticeship Sponsor + 1 more | Jun 30, 2027 |
| Tolland, CT | Eastern Drill Company | B949DF0E51 | Apprenticeship Sponsor | Jun 30, 2015 |
| Bozrah, CT | Eastern Ducts LLC dba Kennedy Sheet Metal | 6AB67D097B | Apprenticeship Sponsor | Jun 30, 2027 |
| Newington, CT | Eastern Electric Systems Co., Inc. | 0DF0514816 | Apprenticeship Sponsor | Jun 30, 2010 |
| Stafford Springs, CT | Eastern Electric, Inc. | 0CE2AAFE6B | Apprenticeship Sponsor | Jun 30, 2021 |
| Naugatuck, CT | Eastern Electrical Contractors LLC | CA1B90E1F4 | Apprenticeship Sponsor | Jun 30, 2006 |
Alphabetical order — this site ranks no one. Businesses with at least one active credential in the Connecticut eLicensing file of October 1, 2026. How to read this.