FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person *   Helwig David R 2. Date of Event Requiring Statement (Month/Day/Year) 08/30/2007 3. Issuer Name and Ticker or Trading Symbol QUANTA SERVICES INC [PWR] (Last) (First) (Middle) 1360 POST OAK BOULEVARD, SUITE 2100 4. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) 5. If Amendment, Date Original Filed(Month/Day/Year) (Street) HOUSTON, TX 77056-3023 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Beneficially Owned

1.Title of Security (Instr. 4) 2. Amount of Securities Beneficially Owned (Instr. 4) 3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 4. Nature of Indirect Beneficial Ownership (Instr. 5) Common Stock (1) 472,222 (2) I By DRHCLH Partnership, LP (3) Common Stock 35,711 (4) D Â

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.			SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Options (Right to buy)	08/30/2007	11/06/2016	Common Stock	59,070 (5)	$ 16.81	D	Â
Stock Options (Right to buy)	08/30/2007	05/06/2014	Common Stock	28,483 (6)	$ 10.63	D	Â
Stock Options (Right to buy)	08/30/2007	05/06/2014	Common Stock	108,719 (7)	$ 10.63	D	Â
Stock Options (Right to buy)	08/30/2007	11/28/2015	Common Stock	61,150 (8)	$ 9.66	D	Â
Stock Options (Right to buy)	08/30/2007	09/23/2013	Common Stock	143,059 (9)	$ 3.77	D	Â

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Helwig David R 1360 POST OAK BOULEVARD, SUITE 2100 HOUSTON, TX 77056-3023	  X	Â	Â	Â

Signatures

/s/ Tana L. Pool, Atty-in-Fact		08/31/2007
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 5(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Exhibit 24 - Power of Attorney
(2)	Received in exchange for 386,118 shares of InfraSource Services, Inc. ("IFS") common stock in connection with the merger of IFS into Quanta Services, Inc. ("Quanta") (the "Merger") using the exchange ratio of 1.223 shares of Quanta common stock for each share of IFS common stock.
(3)	Mr. Helwig has sole dispositive power over the stock held by the partnership.
(4)	Received in the Merger in exchange for 29,200 shares of IFS common stock using the exchange ratio of 1.223 shares of Quanta common stock for each share of IFS common stock.
(5)	Received in the Merger in exchange for an employee stock option to acquire 48,300 shares of IFS common stock for $20.55 per share. Such options were converted into options to acquire Quanta common stock using the exchange ratio of 1.223 shares of Quanta common stock for each share of IFS common stock. In connection with the change of control of IFS resulting from the Merger, all unvested options became fully vested on August 30, 2007.
(6)	Received in the Merger in exchange for an employee stock option to acquire 23,290 shares of IFS common stock for $13.00 per share. Such options were converted into options to acquire Quanta common stock using the exchange ratio of 1.223 shares of Quanta common stock for each share of IFS common stock. In connection with the change of control of IFS resulting from the Merger, all unvested options became fully vested on August 30, 2007.
(7)	Received in the Merger in exchange for an employee stock option to acquire 88,896 shares of IFS common stock for $13.00 per share. Such options were converted into options to acquire Quanta common stock using the exchange ratio of 1.223 shares of Quanta common stock for each share of IFS common stock. In connection with the change of control of IFS resulting from the Merger, all unvested options became fully vested on August 30, 2007.
(8)	Received in the Merger in exchange for an employee stock option to acquire 50,000 shares of IFS common stock for $11.81 per share. Such options were converted into options to acquire Quanta common stock using the exchange ratio of 1.223 shares of Quanta common stock for each share of IFS common stock. In connection with the change of control of IFS resulting from the Merger, all unvested options became fully vested on August 30, 2007.
(9)	Received in the Merger in exchange for an employee stock option to acquire 116,974 shares of IFS common stock for $4.60 per share. Such options were converted into options to acquire Quanta common stock using the exchange ratio of 1.223 shares of Quanta common stock for each share of IFS common stock. In connection with the change of control of IFS resulting from the Merger, all unvested options became fully vested on August 30, 2007.

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