POWER OF ATTORNEY LETTER

POWER OF ATTORNEY

Know all by these present, that the undersigned hereby constitutes and
appoints Vincent A. Mercaldi, signing singly, the undersigned's true and
lawful attorney-in-fact to:

1 execute for and on behalf of the undersigned, in the undersigned's
capacity as a director and or officer of Quanta Services, Inc. the "Company",
Forms 3, 4, and 5 in accordance with Section 16a of the Securities Exchange
Act of 1934 and the rules thereunder

2 do and perform any and all acts for and on behalf of the undersigned
which may be necessary or desirable to complete and execute any such Form 3,
4, or 5, complete and execute any amendment or amendments thereto, and timely
file such form with the United States Securities and Exchange Commission and
any stock exchange or similar authority and

3 take any other action of any type whatsoever in connection with the
foregoing which, in the opinion of such attorney in fact, may be of benefit
to, in the best interest of, or legally required by, the undersigned, it
being understood that the documents executed by such attorney in fact on
behalf of the undersigned pursuant to this Power of Attorney shall be in
such form and shall contain such terms and conditions as such attorney in
fact may approve in such attorney in facts discretion.

The undersigned hereby grants to such attorney in-fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary, or proper to be done in the exercise of any of the rights and
powers herein granted, as fully to all intents and purposes as the undersigned
might or could do if personally present, with full power of substitution or
revocation, hereby ratifying and confirming all that such attorney in fact,
or such attorney in fact's substitute or substitutes, shall lawfully do or
cause to be done by virtue of this power of attorney and the rights and
powers herein granted. The undersigned acknowledges that the foregoing
attorney in-fact, in serving in such capacity at the request of the
undersigned, are not assuming, nor is the Company assuming, any of the
undersigned's responsibilities to comply with Section 16 of the Securities
Exchange Act of 1934.

This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file Forms 3, 4, and 5 with respect
to the undersigned's holdings of and transactions in securities issued by
the Company, unless earlier revoked by the undersigned in a signed writing
delivered to the foregoing attorney in fact.

IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney
to be executed as of this 25th day of November, 2005.
s/ John R. Wilson