EXHIBIT 21.1 STATE OF SUBSIDIARY INCORPORATION -------------------------------------------------- --------------------- Advanced Technologies and Installation Washington Corporation Airlan Telecom Services, L.P. Texas Allteck Line Contractors (USA), Inc. Washington Allteck Line Contractors, Inc. British Columbia Arby Construction, Inc. Delaware Austin Trencher, Inc. Delaware Bradford Brothers, Inc. North Carolina Brown Engineering, LLC Delaware CCLC, Inc. Delaware Coast to Coast, LLC California Communication Manpower, Inc. Florida Conti Communications, Inc. Delaware Croce Electric Company, Inc. Delaware Crown Fiber Communications, Inc. Virginia Choice Optics Communications DeltaComm Fiber Technology Marlboro Cablevision World Fiber Digco Utility Construction, L.P. Texas Dillard Smith Construction Company Delaware Dot 05, LLC Delaware Driftwood Electrical Contractors, Inc. Delaware Maddux Communications Environmental Professional Associates, Limited California Provco Five Points Construction Co. Texas Global Enercom Management, Inc. Delaware Golden State Utility Co. Delaware H.L. Chapman Pipeline Construction, Inc. Delaware DB Utilities Haines Construction Company Delaware Intermountain Electric, Inc. Colorado Grand Electric Irby Construction Company Mississippi Lake Norman Pipeline, LLC North Carolina Lindsey Electric, L.P. Texas Line Equipment Sales Co., Inc. South Carolina Manuel Bros., Inc. Delaware Renaissance Construction Western Directional Mears Canada Corp. Nova Scotia Mears Engineering, LLC Michigan Mears Group, Inc. Delaware Mears Services, LLC Michigan Mears/CPG, LLC Michigan 1 STATE OF SUBSIDIARY INCORPORATION -------------------------------------------------- --------------------- Mears/HDD, LLC Michigan Mearsmex de R.L. de C.V. Mexico Mejia Personnel Services, Inc. Texas Metro Underground Services, Inc. Illinois Network Electric Company Delaware North Houston Pole Line, L.P. Texas North Houston Pole Line Corp. North Pacific Construction Co., Inc. Delaware North Sky Communications, Inc. Delaware Northern Line Layers, LLC Delaware Okay Construction Company, LLC Delaware P.D.G. Electric Co. Florida PAR Electrical Contractors, Inc. Missouri Harker & Harker Par Infrared Consultants Riggin & Diggin Line Construction Union Power Construction Company Parkside Site and Utility Company Corporation Delaware Parkside Utility Construction Corp. Delaware Potelco, Inc. Washington Kingston Constructors Kingston Constructors DBA Talking Signs Services Kuenzi Construction NorAm Telecommunications Professional Teleconcepts, Inc. Illinois Professional Teleconcepts, Inc. New York PWR Financial Company Delaware PWR Network, LLC Delaware Q Resources, LLC Delaware QDE LLC Delaware QPC, Inc. Delaware QSI, Inc. Delaware Quanta Asset Management LLC Delaware Quanta Associates, L.P. Texas Quanta Delaware, Inc. Delaware Quanta Holdings, Inc. Delaware Quanta LI Acquisition, Inc. Delaware Quanta LIV Acquisition, Inc. Delaware Quanta LIX Acquisition, Inc. Delaware Quanta LVII Acquisition, Inc. Delaware Quanta LVIII Acquisition, Inc. Delaware Quanta LX Acquisition, Inc. Delaware Quanta LXI Acquisition, Inc. Delaware Quanta LXII Acquisition, Inc. Delaware Quanta LXIII Acquisition, Inc. Delaware Quanta LXIV Acquisition, Inc. Delaware Quanta LXIX Acquisition, Inc. Delaware Quanta LXV Acquisition, Inc. Delaware Quanta LXVI Acquisition, Inc. Delaware 2 STATE OF SUBSIDIARY INCORPORATION -------------------------------------------------- --------------------- Quanta LXVII Acquisition, Inc. Delaware Quanta LXVIII Acquisition, Inc. Delaware Quanta LXX Acquisition, Inc. Delaware Quanta LXXI Acquisition, Inc. Delaware Quanta LXXII Acquisition, Inc. Delaware Quanta LXXIII Acquisition, Inc. Delaware Quanta XXXI Acquisition, Inc. Delaware Quanta Receivables, L.P. Delaware Quanta Services Management Partnership, L.P. Texas Quanta Services of Canada Ltd. British Columbia Quanta Utility Installation Co., Inc. Delaware R.A. Waffensmith & Co., Inc. Delaware Ranger Field Services, Inc. Delaware Brown Engineering & Testing S.K.S. Pipeliners, LLC Delaware Seaward Corporation Maine Interstate Equipment Corporation Southeast Pipeline Construction, Inc. Delaware Southwestern Communications, Inc. Delaware NetCom Management Group, Inc. TVS Systems Spalj Construction Company Delaware Dot 05 Optical Communications Span-Con of Deerwood Tjader & Highstrom Wilson Roadbores Sumter Utilities, Inc. Delaware The Ryan Company, Inc. Massachusetts Eastern Communications Tjader, L.L.C. Delaware TNS-VA, LLC Delaware Tom Allen Construction Company Delaware Trans Tech Acquisition, Inc. Texas Trans Tech Electric, L.P. Texas Trawick Construction Co. Florida TTGP, Inc. Delaware TTLP, Inc. Delaware TTM, Inc. North Carolina TXLP, Inc. Delaware Underground Construction Co., Inc. Delaware Utilco, Inc. Georgia VCI Telcom, Inc. Delaware W. C. Communications, Inc. Delaware W.H.O.M. Corporation California 3