EXHIBIT 10.33

AMENDMENT NO. 1
TO
NOTE PURCHASE AGREEMENT

This AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT (this "Amendment"),
dated as of August 12, 2002, is made by and among each of QUANTA SERVICES, INC.,
a Delaware corporation (the "Company") and each of the institutions listed on
Annex 1 hereto (such institutions being collectively referred to as the
"Noteholders").

BACKGROUND

1. The Company and certain of the Noteholders are parties to that
certain Note Purchase Agreement (the "Original Note Purchase Agreement"), dated
as of March 1, 2000, that provides, among other things, for the sale by the
Company and the purchase by certain of the Noteholders of up to (a)
Seventy-Three Million Dollars ($73,000,000) in aggregate principal amount of the
Company's 8.46% Series 2000-A Senior Secured Notes, Tranche 1, due March 1, 2005
(the "Series A-1 Notes"), (b) Forty-One Million Five Hundred Thousand Dollars
($41,500,000) in aggregate principal amount of the Company's 8.55% Series 2000-A
Senior Secured Notes, Tranche 2, due March 1, 2007 (the "Series A-2 Notes") and
(c) Thirty-Five Million Five Hundred Thousand Dollars ($35,500,000) in aggregate
principal amount of the Company's 8.61% Series 2000-A Senior Secured Notes,
Tranche 3, due March 1, 2010 (the "Series A-3 Notes" and, collectively with the
Series A-1 Notes and the Series A-2 Notes, the "Series A Notes"). All of the
Series A Notes are currently outstanding.

2. The Original Note Purchase Agreement has been supplemented in
certain respects pursuant to a First Supplement to Note Purchase Agreement (the
"First Supplement" and, together with the Original Note Purchase Agreement, the
"Existing Note Purchase Agreement"), dated as of September 1, 2000, by and among
the Company and certain of the Noteholders, that provides, among other things,
for the sale by the Company and the purchase by certain of the Noteholders of up
to (a) Thirty Million Dollars ($30,000,000) in aggregate principal amount of the
Company's 8.01% Series 2000-B Senior Secured Notes, Tranche 1, due September 1,
2005 (the "Series B-1 Notes"), (b) Five Million Dollars ($5,000,000) in
aggregate principal amount of the Company's 8.06% Series 2000-B Senior Secured
Notes, Tranche 2, due September 1, 2006 (the "Series B-2 Notes") and (c)
Twenty-Five Million Dollars ($25,000,000) in aggregate principal amount of the
Company's 8.29% Series 2000-B Senior Secured Notes, Tranche 3, due September 1,
2010 (the "Series B-3 Notes" and, collectively with the Series B-1 Notes and the
Series B-2 Notes, the "Series B Notes" and the Series B Notes, together with the
Series A Notes, the "Notes"). All of the Series B Notes are currently
outstanding.

3. The Company has requested of the Noteholders that the Existing Note
Purchase Agreement and the Notes be amended to the effect and as set forth in
this Amendment.

NOW, THEREFORE, in order to induce the Noteholders to amend the
Existing Note Purchase Agreement and the Notes and for other good and valuable
consideration (the receipt and sufficiency of which are hereby acknowledged),
the Company agrees with the Noteholders as follows:

SECTION 1. DEFINED TERMS.

All capitalized terms used, but not specifically defined, in this
Amendment have the respective meanings assigned to them in the Existing Note
Purchase Agreement.

SECTION 2. WARRANTIES AND REPRESENTATIONS.

The Company warrants and represents to each Noteholder that as of the
date of this Amendment and as of the Effective Date (as defined in Section 3):

2.1 CORPORATE ORGANIZATION AND AUTHORITY. The Company is a corporation
duly organized, validly existing and in good standing under the laws of its
jurisdiction of incorporation, and is duly qualified as a foreign corporation
and is in good standing in each jurisdiction in which such qualification is
required by law, other than those jurisdictions as to which the failure to be so
qualified or in good standing could not, individually or in the aggregate,
reasonably be expected to have a Material Adverse Effect. The Company has the
corporate power and authority to transact the business it transacts and proposes
to transact, to execute and deliver this Amendment and to perform the provisions
hereof.

2.2 NO MATERIAL ADVERSE CHANGE. Since December 31, 2001, except as
disclosed in writing to the Noteholders, there has been no change in the
business, operations, affairs, financial condition, assets or properties of the
Company except for

(a) changes in general, economic, market and industry
conditions that are generally applicable to the Company and all other
Persons that are in the same or similar businesses as the Company and
are similarly situated, and

(b) changes in the ordinary course of business,

that in the aggregate for all such changes, could not reasonably be expected to
have a Material Adverse Effect.

2.3 FULL DISCLOSURE. Each written statement and all written materials
furnished by, or on behalf of, the Company to the Noteholders pursuant to
Sections 7.1 and 7.2 of the Existing Note Purchase Agreement, taken as a whole,
and each written statement and all written materials furnished by, or on behalf
of, the Company to the Noteholders in connection with this Amendment, taken as a
whole, do not contain any untrue statement of a material fact or omit a material
fact necessary to make the statements contained therein not misleading in light
of the circumstances made. There is no fact known to the Company which the
Company has not disclosed to the Noteholders in writing which could reasonably
be expected to have a Material Adverse Effect.

2.4 TRANSACTION IS LEGAL AND AUTHORIZED. The execution and delivery of
this Amendment by the Company, the consummation of each of the transactions
contemplated by this Amendment and the compliance by the Company with all the
provisions of this Amendment:

(a) are within the corporate powers of the Company;

(b) are in compliance with applicable law;

(c) do not conflict with, result in any breach in any of the
provisions of, constitute a default under, or result in the creation of
any Lien upon any property of the Company under the

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

provisions of, any order, judgment, decree, or ruling of any court, arbitrator
or Governmental Authority applicable to the Company; and

(d) do not conflict with, result in any material breach of any
of the provisions of, constitute a material default under, or result in
the creation of any Lien not permitted by Section 10.5 of the Existing
Note Purchase Agreement upon any property of the Company under the
provisions of, any agreement, indenture, charter instrument, bylaw or
other constitutive document or instrument to which it is a party or by
which it or any of its property is bound.

2.5 AMENDMENT IS ENFORCEABLE. This Amendment is a legal, valid and
binding and enforceable obligation of the Company, enforceable against the
Company in accordance with its terms, except as the enforceability hereof may be
limited by applicable bankruptcy, reorganization, arrangement, insolvency,
moratorium or other similar laws affecting the enforceability of creditors'
rights generally and the application of general equitable principles.

2.6 NO DEFAULTS. The Company is not in violation in any respect of any
term in any agreement or other instrument to which it is a party or by which it
or any of its property may be bound, except for such violations that, in the
aggregate for all such violations, could not reasonably be expected to have a
Material Adverse Effect.

2.7 PENDING LITIGATION.

(a) There are no proceedings, actions or investigations
pending, or to the knowledge of the Company, threatened against or
affecting the Company in any court or before any Governmental Authority
or arbitration board or tribunal that, in the aggregate for all such
proceedings, actions and investigations, could reasonably be expected
to have a Material Adverse Effect.

(b) The Company is not in default with respect to any
judgment, order, writ, injunction or decree of any court, Governmental
Authority, arbitration board or tribunal that, in the aggregate for all
such defaults, could reasonably be expected to have a Material Adverse
Effect.

2.8 COMPLIANCE WITH LAW. The Company is not in violation of any law,
ordinance, governmental rule or regulation to which it is subject, except for
such violations that, in the aggregate for all such violations, could not
reasonably be expected to have a Material Adverse Effect.

2.9 NO DEFAULTS. After giving effect to this Amendment, no Default or
Event of Default will exist.

SECTION 3. CONDITIONS PRECEDENT.

This Amendment shall have no effect until all of the following
conditions precedent shall have been fulfilled (such time of effectiveness being
herein referred to as the "Effective Date"):

(a) WARRANTIES AND REPRESENTATIONS TRUE. After giving effect
to this Amendment, the warranties and representations set forth in the
Existing Note Purchase Agreement and in Section 2

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

to this Amendment shall be true in all material respects (unless
specifically limited to an earlier date, in which case, such
representations and warranties were true as of such date).

(b) NO PROHIBITED ACTION. No Default or Event of Default shall
exist after giving effect to, the consummation of the transactions
contemplated by this Amendment.

(d) OPINIONS OF COUNSEL. The Noteholders shall have received
legal opinions from General Counsel and special counsel to Company and
the Guarantors, in form and substance satisfactory to them.

(e) AMENDMENT OF BANK CREDIT AGREEMENT. An Eighth Amendment to
the Third Amended and Restated Secured Credit Agreement among the
Company, as Borrower, the Financial Institutions party thereto, as
Lenders, Bank of America, N.A., as Administrative Agent, and the other
agents named therein (as amended, the "Bank Credit Agreement") shall
have been entered into by the Company and the Majority Lenders (as such
term is defined in the Bank Credit Agreement), shall contain terms
satisfactory to the Noteholders, and shall be in full force and effect,
subject only to the effectiveness of this Amendment.

(f) COMPLIANCE CERTIFICATES. The Secretary or Assistant
Secretary and the President or the Vice President of the Company and
each Guarantor shall have delivered to each Noteholder a certificate,
dated the date hereof, certifying as to the resolutions attached
thereto and other corporate proceedings relating to the authorization,
execution and delivery of this Amendment or its consent, as applicable,
containing substantially the substance of Attachment A hereto.

(g) PAYMENT OF NOTEHOLDER FEES AND EXPENSES. The Company shall
have paid all fees and expenses of the Noteholders incurred in
connection with this Amendment for which invoices have been delivered,
including the fees and expenses of Bingham McCutchen LLP and Chapman &
Cutler.

(h) GUARANTORS' CONSENT. The Guarantors shall have executed
and delivered the Consent attached hereto as Attachment B.

(i) PAYMENT OF AMENDMENT FEE. The Company shall have paid each
Noteholder an amendment fee equal to 0.375% of the aggregate
outstanding principal amount of the Notes held by such Noteholder.

(j) PROCEEDINGS SATISFACTORY. All proceedings taken in
connection with the execution and delivery of this Amendment and the
transactions contemplated hereby shall be satisfactory to the
Noteholders and their special counsel; and the Noteholders and their
special counsel shall have received copies of such documents and papers
as they may reasonably request in connection with the execution and
delivery of this Amendment.

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

SECTION 4. AFFIRMATIVE COVENANTS

4.1 COLLATERAL REVIEW. Within sixty (60) days of the Effective Date,
the Noteholders shall select a nationally recognized accounting firm (the
"Financial Advisor") to perform a review of the Company's finances including,
without limitation, a review of the Collateral and an examination of the
Company's and its Subsidiaries' accounts receivable, work-in-process, backlog
and other matters reasonably requested by the Noteholders. The Company shall pay
all reasonable fees and expenses of the Financial Advisor.

4.2 REAL ESTATE COLLATERAL. Without limiting the terms, covenants,
conditions or other obligations set forth in Section 9.6 of the Existing Note
Purchase Agreement, within sixty (60) days of the Effective Date, the Company
shall, and shall cause its Subsidiaries to, execute and deliver mortgages or
deeds or trust, as applicable, and in form and substance satisfactory to the
Required Holders, granting to the Collateral Agent for the benefit of the Bank
Lenders and the Noteholders, a first priority Lien upon, and security interest
in, the real property owned by the following Subsidiaries:

(i) Dillard Smith Construction Company,

(ii) Golden State Utility Co.,

(iii) H.L. Chapman Pipeline Construction, Inc.,

(iv) Mears Group, Inc.

(v) North Houston Pole Line, L.P.,

(vi) PAR Electrical Contractors, Inc.

(vii) Potelco, Inc.,

(viii) R.A. Waffensmith & Company, Inc.

(ix) Sumter Utilities, Inc.

(x) Underground Construction Co., Inc.

Such property shall be subject to no other Liens than Liens permitted by Section
10.5 of the Existing Note Purchase Agreement. In addition, the Company shall, at
its sole cost and expense, deliver such surveys, mortgagee title policies,
environmental assessment reports, evidence of insurance from an insurer
acceptable to the Required Holders naming the Collateral Agent (as such term is
defined in the Intercreditor Agreement) as "loss payee" and "additional
insured", as the case may be, and other related documents reasonably requested
by the Required Holders, in each case in form and substance satisfactory to the
Required Holders.

4.3 NOTICE OF INTEREST RATE CHANGES. Within sixty (60) days after the
end of each quarterly fiscal period in each fiscal year, the Company shall
provide each Noteholder with a calculation of the Applicable Margin for such
quarterly fiscal period, which, in the case of the first three fiscal quarters
of each

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

fiscal year, may be included in the compliance certificate required by Section
7.2(a) of the Existing Note Purchase Agreement.

4.4 SPECIAL PREPAYMENT OF PRINCIPAL. Promptly after the receipt
thereof, the Company shall apply:

(a) one hundred percent (100%) of the net proceeds from
collections of that portion of any accounts receivable owed by account
debtors previously specified in writing to the Noteholders that have
been written off as doubtful of collection and which are included in
the definition of "Permitted Charges", and

(b) one hundred percent (100%) of the net proceeds of asset
sales made pursuant to Section 10.7(d) or Section 10.7(e),

in each case, to prepayment of the principal amount of the Notes and
the Debt under the Bank Credit Agreement, pro-rata, based upon the Bank
Lenders' (as such term is defined in the Bank Credit Agreement)
Commitment Amount at such time and the aggregate outstanding principal
amount of the Notes at such time. Modified Make-Whole Amount shall be
due and payable, from such proceeds, with respect to any such
prepayment of Notes under this Section 4.4. Amounts paid to the
Noteholders pursuant to this Section 4.4 shall be applied first to the
applicable Modified Make-Whole Amount and the remainder to the
principal amount of the Notes. For purposes of this Section 4.4, "net
proceeds" shall mean all proceeds of such sale or other disposition net
of usual and customary transaction costs and expenses actually incurred
in connection with such sale or disposition.

SECTION 5. AMENDMENTS TO EXISTING NOTE PURCHASE AGREEMENT.

5.1 The definition of "Change of Control" contained in Section 8.7(h)
of the Existing Note Purchase Agreement is hereby amended by adding the
following after "directors" appearing in the eighth line thereof:

"; or, individuals who on June 14, 1999, constituted the
Company's Board of Directors, or their approved successors,
cease for any reason to constitute at least a majority of the
Company's Board of Directors. An approved successor is a new
director elected when the election or nomination for the
election by the Company's stockholders of such new director
was approved by a vote of at least two-thirds of the directors
then still in office who were directors on June 14, 1999, or
their approved successors."

5.2 Article 9 of the Existing Note Purchase Agreement is hereby amended
by adding the following new Section 9.7:

"9.7. Maintenance of Most Favored Lender Status. The Company
hereby acknowledges and agrees that if, on or before June 30, 2004, the
Company shall enter into any agreement or amendment with any lender or
holder of its Funded Debt which provides, for the benefit of any such
lender or holder, any covenant that is in addition to, or more
favorable to such Person than, the covenants contained in this
Agreement, then, and in each and any such event, the covenants in this
Agreement shall be, and shall be deemed to be, without any further
action on the

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

part of the Company or any other Person being necessary or required,
amended to afford the holders of the Notes the same benefits and rights
with respect to such matters as such agreements or amendments provide
to any such other lender or holder. In addition, if, on or before June
30, 2004, the Company amends the Bank Credit Agreement to increase the
Applicable Margin paid to the Bank Lenders thereunder, the Company will
execute and deliver to the Noteholders an amendment to this Agreement
to provide the Noteholders a corresponding increase in the Applicable
Margin. The Company will promptly deliver to each holder of Notes a
copy of each such agreement or amendment entered into after the date
hereof. Without limiting the effectiveness of the first sentence of
this Section 9.7, the Company agrees, no later than thirty (30) days
following the date of such agreement or amendment, to enter into such
documentation as the Required Holders may reasonably request to
evidence the amendments provided for in this Section 9.7."

5.3 Section 10.1 of the Existing Note Purchase Agreement is hereby
amended and restated in its entirety to read as follows:

"Section 10.1 Minimum Consolidated Net Worth. Prior to June
30, 2004, the Company will maintain a minimum Consolidated Net Worth of
not less than an amount equal to the sum of (a) 90% of Consolidated Net
Worth as of June 30, 2002 (determined without giving effect to any
adjustments made in accordance with FAS 142), plus (b) for each fiscal
quarter ended prior to (but not on) such date of determination,
commencing with the fiscal quarter ended June 30, 2002, the sum of (i)
an amount equal to 75% of Consolidated Net Income for such fiscal
quarter, if positive, plus (ii) an amount equal to 100% of the amount
of any equity issuance by the Company, including equity issued in a
secondary offering or equity issued to acquire another entity in an
Acquisition, minus (iii) any distributions to shareholders of any
Subchapter S corporation acquired in an Acquisition as a result of
operations of such corporation prior to the closing of the Acquisition,
minus (iv) Permitted Charges referenced in clauses (a) and (b) of such
definition which are applicable to such period, and minus (v) charges
taken in accordance with FAS 142 in conformity with GAAP at any time
during the period from June 30, 2002 to and including June 30, 2004,
which do not exceed $800,000,000 in the aggregate. Increases in
Consolidated Net Worth required after June 30, 2002 shall be
appropriately adjusted to eliminate any adverse effects on the
Consolidated Net Worth of the Company occasioned by the expensing of
Modified Make-Whole Amounts paid pursuant to Section 4.4 of Amendment
No. 1. The calculation of Consolidated Net Worth under this Section
10.1 shall not take into consideration the non-cash charges related to
the Company's stock option program or stock compensation plan required
to be taken pursuant to GAAP". Subsequent to June 30, 2004, the
foregoing provisions of this Section 10.1 shall continue to be
applicable in all respects except that the percentage of Consolidated
Net Income required to be added each quarter shall be reduced from 75%
to 50%.

5.4 Section 10.2 of the Existing Note Purchase Agreement is hereby
amended and restated in its entirety to read as follows:

"Section 10.2. Limitation on Consolidated Debt. The Company
will not, as of the final day of any period of four consecutive fiscal
quarters of the Company ending at any time during any period specified
below, permit the ratio of Funded Debt at such time to EBITDA for the

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

trailing four quarter period (in each case for the Company and its
Subsidiaries on a consolidated basis) to be greater than the ratio set
forth below opposite such period:

<Table>
<Caption>
PERIOD RATIO
- ------ -----

June 30, 2002 3.50 to 1.00
July 1, 2002 through September 30, 2002 4.30 to 1.00
October 1, 2002 through December 31, 2002 4.40 to 1.00
January 1, 2003 through March 31, 2003 4.50 to 1.00
April 1, 2003 through June 30, 2003 4.10 to 1.00
July 1, 2003 through September 30, 2003 4.00 to 1.00
October 1, 2003 and at all times thereafter 3.50 to 1.00"
</Table>

5.5 Section 10.4 of the Existing Note Purchase Agreement is hereby
amended and restated in its entirety to read as follows:

"Section 10.4. Minimum Interest Coverage Ratio. The Company
will not, for any period of four consecutive fiscal quarters of the
Company ending at any time during any period specified below, permit
the Minimum Interest Coverage Ratio to be less than the ratio set forth
below opposite such period:

<Table>
<Caption>
PERIOD RATIO
- ------ -----

June 30, 2002 3.00 to 1.00
July 1, 2002 through September 30, 2002 2.40 to 1.00
October 1, 2002 through December 31, 2002 2.00 to 1.00
January 1, 2003 through March 31, 2003 1.70 to 1.00
April 1, 2003 through June 30, 2003 1.90 to 1.00
July 1, 2003 through September 30, 2003 2.10 to 1.00
October 1, 2003 through June 30, 2004 2.30 to 1.00
July 1, 2004 and at all times thereafter 2.50 to 1.00"
</Table>

5.6 Section 10.7 of the Existing Note Purchase Agreement is hereby
amended and restated in its entirety to read as follows:

"Section 10.7. Sale of Assets. The Company will not, and will
not permit any Subsidiary to, sell, lease or otherwise dispose of any
of the assets of the Company and its Subsidiaries; except for:

(a) transfers of inventory in the ordinary course of business;

(b) retirement or replacement of assets (with assets of equal
or greater value) in the ordinary course of business;

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

(c) transfers of any assets (i) to a non-domestic Subsidiary
of the Company not to exceed $5,000,000 in the aggregate; and
(ii) among the Company and any of its domestic subsidiaries.

(d) sales, transfers or conveyances of accounts receivable for
fair and adequate consideration and for cash; provided that
all proceeds from the sale, transfer or conveyance of such
assets are applied in accordance with Section 4.4 of Amendment
No. 1; and

(e) dispositions which generate net proceeds of up to (i)
$50,000,000 in the aggregate during the period from the
Effective Date through June 14, 2004, and (ii) $50,000,000 in
any period of twelve (12) consecutive months during the period
from June 15, 2004, through September 1, 2010; provided that
the aggregate net proceeds generated by asset dispositions
during the period June 15, 2004 through September 1, 2010
shall not exceed $150,000,000; and provided further that one
hundred percent (100%) of all such proceeds received on and
after the Effective Date shall be applied in accordance with
Section 4.4 of Amendment No. 1."

5.7 Section 10.9 of the Existing Note Purchase Agreement is hereby
amended and restated in its entirety to read as follows:

"Section 10.9. Transactions with Affiliates. The Company will
not and will not permit any Subsidiary to enter into directly or
indirectly any Material transaction or Material group of related
transactions (including without limitation the purchase, lease, sale or
exchange of properties of any kind or the rendering of any service)
with any Affiliate (other than the Company or another Subsidiary),
except upon fair and reasonable terms no less favorable to the Company
or such Subsidiary than would be obtainable in a comparable
arm's-length transaction with a Person not an Affiliate.
Notwithstanding anything in this Section 10.9 to the contrary, neither
the Company nor any of its Subsidiaries shall, at any time, make or
have outstanding any loans or advances to any employee, stockholder,
officer or director of the Company or any of its Subsidiaries, except
loans and advances which do not at any time aggregate more than
$2,000,000 at any time outstanding prior to June 30, 2004, and more
than $5,000,000 at any time outstanding thereafter and which are made
in compliance with all applicable laws and regulations.

5.8 Article 10 of the Existing Note Purchase Agreement is hereby
amended by adding the following new Section 10.11:

"Section 10.11. Maximum Senior Debt to EBITDA. The Company
will not, as of the final day of any period of four consecutive fiscal
quarters of the Company ending at any time during any period specified
below, permit the ratio of Senior Debt at such time to EBITDA for the
trailing four quarter period (in each for the Company and its
Subsidiaries on a consolidated basis) to be greater than the ratio set
forth below opposite such period:

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

<Table>
<Caption>
PERIOD RATIO
- ------ -----

June 30, 2002 3.00 to 1.00
July 1, 2002 through March 31, 2003 3.10 to 1.00
April 1, 2003 through June 30, 2003 2.80 to 1.00
July 1, 2003 through September 30, 2003 2.75 to 1.00
October 1, 2003 through June 30, 2004 2.50 to 1.00
July 1, 2004 and thereafter 2.75 to 1.00"
</Table>

5.9 Article 10 of the Existing Note Purchase Agreement is hereby
amended by adding the following new Section 10.12:

"Section 10.12. Minimum Asset Coverage. The Company will not,
on the final day of any month ending during any period specified below,
permit the Minimum Asset Coverage Ratio to be less than the ratio set
forth below opposite such period:

<Table>
<Caption>
PERIOD RATIO
- ------ -----

Effective Date through December 31, 2002 1.55 to 1.00
January 1, 2003 through June 30, 2004 1.65 to 1.00
July 1, 2004 and thereafter 1.50 to 1.00"
</Table>

5.10 Article 10 of the Existing Note Purchase Agreement is hereby
amended by adding the following new Section 10.13:

"Section 10.13. Limitation on Acquisitions. Neither the
Company nor any Subsidiary shall make an Acquisition prior to January
1, 2005."

5.11 Article 10 of the Existing Note Purchase Agreement is hereby
amended by adding the following new Section 10.14:

"Section 10.14. Limitation on Restricted Payments. The Company
shall make no Restricted Payment prior to September 21, 2005 other than
required dividends in respect of currently outstanding Preferred Stock,
not to exceed $1,000,000 in any year. Thereafter, the Company may make
aggregate Restricted Payments each year of up to $3,000,000, and may
make Restricted Payments in excess of $3,000,000 in any year to the
extent that the aggregate amount of such payments in excess of
$3,000,000 made after September 21, 2005, does not at any time exceed
the sum of (i) 50% of Consolidated Net Income generated, plus (ii) 50%
of the net proceeds received by the Company from sales of its equity
securities, in each case subsequent to December 31, 2003, plus (iii)
$10,000,000. Anything to the contrary in the foregoing notwithstanding,
the Company shall make no Restricted Payment at any time if a Default
or Event of Default exists or would exist after giving effect to such
payment."

5.12 Article 10 of the Existing Note Purchase Agreement is hereby
amended by adding the following new Section 10.15:

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

"Section 10.15. Capital Expenditures Limitation. (a) Neither
the Company nor any of its Subsidiaries shall make or commit
to make Capital Expenditures greater than (i) for fiscal year
2002, $60,000,000, (ii) for fiscal year 2003 and 2004,
$50,000,000 and (iii) for each fiscal year thereafter,
$85,000,000. No portion of any annual limit may be carried
forward to a subsequent fiscal year.

(b) In addition to the annual limits under subsection
(a) of this Section 10.15, if the Company executes an eligible
contract, then the Company may make Capital Expenditures in
respect of such contract in an amount equal to the lesser of
(i) the actual amount required by such contract, and (ii)
$15,000,000, provided that, (A) in respect of each such
contract, Capital Expenditures not made within 12 months after
the date of such contract shall be applied against the annual
limits under subsection (a) of this Section 10.15, and (B) the
amount of Capital Expenditures under this Section 10.15(b) for
all such contracts may not, in the aggregate, exceed
$15,000,000 in any fiscal year. Upon execution of each
eligible contract, the Company shall promptly deliver a copy
of such contract to each Noteholder, together with a summary
of the Capital Expenditures required by such contract in form
and detail acceptable to the Noteholders. As used in this
Section 10.15(b), "eligible contract" means, a utility
outsourcing contract with revenues to the Company of at least
$75,000,000 during any 12 consecutive month period prior to 18
months after execution of such contract."

5.13 Article 10 of the Existing Note Purchase Agreement is hereby
amended by adding the following new Section 10.16:

"Section 10.16. Additional Indebtedness. Prior to June 30,
2004 or any refinancing of the Bank Credit Agreement existing on the
date of Amendment No. 1, the Company and its Subsidiaries shall not
incur, assume or suffer to exist any Debt (including, without
limitation, any Guaranty), except Debt permitted by Section 6.14 of the
Bank Credit Agreement as in effect on the Effective Date.

5.14 Schedule B of the Existing Note Purchase Agreement is hereby
amended by deleting the definitions of "Enron Subordinated Debt", "Interest
Charges Coverage Ratio" and "Management Fees" set forth therein, and adding the
following definitions in their appropriate alphabetical order as follows:

"ACQUISITION" means a direct or indirect purchase by the
Company or any of its Subsidiaries for cash, stock or other securities
or property, whether in one or more related transactions, of all or
substantially all of the assets, or more than 50% of voting securities
or other equity interests, of a Person or a division, group or other
business unit of a Person. Mergers and consolidations among any one or
more of the Company and its Subsidiaries permitted by Section 10.6 of
this Agreement shall not be considered an Acquisition."

"AMENDMENT NO. 1" means that certain Amendment No. 1 to this
Note Purchase Agreement, dated as of August 12, 2002."

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

"APPLICABLE MARGIN" means, during any fiscal quarter with
respect to which the Company's ratio of Funded Debt to EBITDA is (a)
less than 2.00, .25%; (b) equal to or greater than 2.00 but less than
or equal to 2.50, .50%; (c) more than 2.50 and equal to or less than
3.00, .75%, (d) more than 3.00 and equal to or less than 3.50, 1.00%,
and (e) greater than 3.50, 1.50%; provided, however, that the
Applicable Margin for the period commencing on the Effective Date and
ending September 30, 2002 shall be 1.50%. If at June 30, 2004 or any
time thereafter, the ratio measured by Section 10.2 has been 2.5 or
less for four consecutive quarters, the Applicable Margin shall at all
times thereafter be zero percent (0%)".

"BASE RATE" means, the Series A-1 Base Rate, Series A-2 Base
Rate, Series A-3 Base Rate, Series B-1 Base Rate, Series B-2 Base Rate
or the Series B-3 Base Rate, as applicable."

"CAPITAL EXPENDITURES" means, for any period, the sum, without
duplication, of all expenditures of the Company and its Subsidiaries
for fixed or capital assets made during such period which, in
accordance with GAAP, are required to be classified as capital
expenditures, in each case excluding all such expenditures incurred by
any entity or business acquired in an Acquisition prior to the date of
such Acquisition."

"COMMITMENT AMOUNT" has the meaning ascribed to such term in
the Bank Credit Agreement.

"CONSOLIDATED INTEREST EXPENSE" means, for any period, total
interest expense of the Company and its Subsidiaries on a consolidated
basis for such period in connection with Debt (including, without
limitation, Make-Whole Amount or Modified Make-Whole Amount, as
applicable, paid in connection with the prepayment of the Notes),
determined in accordance with GAAP.

"CONSOLIDATED NET ACCOUNTS" means, as of any date of
determination, accounts receivable set out in the consolidated balance
sheet of the Company and its Subsidiaries as accounts receivable, net
of allowances, and in each case, as determined in accordance with
GAAP."

"CONSOLIDATED NET ASSETS" means, as of any date of
determination, the sum of (a) Consolidated Net Accounts, plus (b)
Consolidated Net PP&E."

"CONSOLIDATED NET PP&E" means, as of any date of
determination, the difference of (a) total property, plant and
equipment of the Company and its Subsidiaries set out in the
consolidated balance sheet of the Company and its Subsidiaries, minus
(b) accumulated depreciation expense attributed to such items, set out
in the consolidated balance sheet of the Company and its Subsidiaries
as "property and equipment, net", and in each case, as determined in
accordance with GAAP."

"CONSOLIDATED NET WORTH" means the consolidated stockholder's
equity of the Company and its Subsidiaries, as determined in accordance
with GAAP.

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

"EBIT" means, for any period, on a trailing four fiscal
quarter basis, the sum of Consolidated Net Income plus, without
duplication, each of the following to the extent actually deducted in
determining Consolidated Net Income: (a) Consolidated Interest Expense;
(b) provisions for taxes based on income or revenues; (c) provisions
made in accordance with FAS 142 which, together with all other charges
theretofore taken in connection with FAS 142, do not exceed
$800,000,000 in the aggregate; (d) to the extent applicable, Permitted
Charges; and (e) non-cash charges related to the Company's stock option
program or stock compensation plan as required to be taken pursuant to
GAAP, in each case calculated on a consolidated basis for the Company
and its Subsidiaries and as determined in accordance with GAAP."

"EBITDA" means, for any period, on a trailing four fiscal
quarter basis (using the historical financial results of any business
acquired in an Acquisition through the Effective Date, to the extent
applicable, all on a pro forma basis, consistent with SEC regulations),
the sum of Consolidated Net Income plus, without duplication, each of
the following to the extent actually deducted in determining
Consolidated Net Income: (a) Consolidated Interest Expense; (b)
provisions for taxes based on income or revenues; (c) the amount of all
depreciation and amortization expense deducted in determining
Consolidated Net Income; (d) charges taken in accordance with FAS 142
which, together with all other charges theretofore taken in connection
with FAS 142, do not exceed $800 million in the aggregate; (e) without
duplication, Permitted Charges; and (f) without duplication, Non-Cash
Charges, all calculated on a consolidated basis for the Company and its
Subsidiaries and as determined in accordance with GAAP. Upon the
consummation of any Acquisition after the Effective Date, EBITDA may be
calculated, subject to the immediately following sentence, using a
calculation which (y) includes the historical financial results of the
acquired business on a pro forma trailing four fiscal quarter basis
(consistent with SEC regulations), and (z) assumes that the
consummation of such Acquisition (and the incurrence, refinancing, or
assumption of any Debt in connection with such Acquisition) occurred on
the first day of the trailing four fiscal quarter period. The foregoing
adjustment to EBITDA to take into account an Acquisition may only be
made if the balance sheet and statements of income, retained earnings,
and cash flows of the acquired Person (or the Person from whom the
assets, securities or other equity interests were acquired), are in
compliance with SEC regulations and requirements regarding the
preparation and presentation of historical financial information and
pro forma financial information."

"FAS 142" means SFAS No. 142 "Goodwill and other Intangible
Assets" promulgated by the Financial Accounting Standards Board in July
2001.

"FUNDED DEBT" means, as of any date of determination, the sum,
without duplication, of the following for the Company and its
Subsidiaries: (i) Debt for borrowed money, all obligations evidenced by
bonds, debentures, notes or similar instruments, and purchase money
obligations which in accordance with GAAP would be shown on the
consolidated balance sheet of the Company as a liability, (ii) all LC
Obligations (as such term is defined in the Bank Credit Agreement), and
all reimbursement obligations relative to the face amount of all other
letters of credit issued for the account of the Company or any of its
Subsidiaries, and (iii) all Capital Lease Obligations.

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

"INTEREST RATE PROTECTION AGREEMENT" means any hedge, swap,
exchange, forward, future collar or cap arrangements, fixed price
agreements or other agreements or arrangements designed to protect
against fluctuations in interest rates.

"MINIMUM ASSET COVERAGE RATIO" means, when determined, the
ratio of (a) Consolidated Net Assets, to (b) Senior Debt."

"MINIMUM INTEREST COVERAGE RATIO" means, for any period, on a
trailing four fiscal quarter basis, the ratio of (a) EBIT, to (b) the
sum of Consolidated Interest Expense (excluding any Make-Whole Amount
or Modified Make-Whole Amount, as applicable, paid in connection with
asset sales which result in a mandatory prepayment on the Senior
Notes), plus the amount of any dividend or distribution recognized in
respect of the Preferred Stock during such period."

"MODIFIED MAKE-WHOLE AMOUNT" means, at any time, the
Make-Whole Amount computed as if interest on each Note will accrue, at
all times, at the Base Rate applicable to such Note, regardless of
whether such Base Rate is the rate of interest currently in effect for
such Note."

"NON-CASH CHARGES" means, for any period, the amount of
non-cash charges during such period properly taken in accordance with
GAAP; provided that, if any cash outlay is made during such period in
respect of such non-cash charge, only the amount of such non-cash
charge which exceeds the amount of the cash outlay may be added back to
Consolidated Net Income for purposes of calculating EBITDA."

"PERMITTED CHARGES" means, for any period, on a trailing four
fiscal quarter basis, expenses, write-offs or losses, which in each
case have been (a) paid, incurred or realized on or before June 30,
2003, (b) disclosed to the Required Holders in such detail as the
Required Holders deem acceptable, and (c) determined in accordance with
GAAP, and which relate to:

(a) employee terminations, equipment sales, operating
lease termination expenses, and real estate lease terminations
(including related clean-up and moving charges) which, in the
aggregate do not exceed $29,000,000, provided that, cash
payments in connection with the items under this clause (a),
may not, in the aggregate, exceed $20,000,000,

(b) accounts receivable, notes receivable, retainage,
costs and earnings in excess of billing, and other amounts
which (i) are either (A) set out in the consolidated balance
sheet of the Company and its Subsidiaries for the fiscal
quarter ended June 30, 2002 as net of allowances or (B)
disclosed in writing to the Required Holders on August 12,
2002 or (ii) relate to the contractual obligations of Company
or its Subsidiaries existing on June 30, 2002 as disclosed in
writing to the Required Holders on August 12, 2002, and which
have been charged off as doubtful for collection, provided
that, such amounts may not, in the aggregate, exceed
$62,000,000,

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

(d) advisory, legal, and bank fees and expenses in
connection with the negotiation, execution and delivery of the
Eighth Amendment to the Bank Credit Agreement and Amendment
No. 1, and related third party due diligence conducted in
connection therewith, and which do not, in the aggregate,
exceed $3,500,000, and (ii) non-cash expenses related to prior
financing transaction costs and expenses which have been
capitalized and are required to be expensed in accordance with
GAAP."

"RESTRICTED PAYMENT" means, in respect of any corporation,
association or other business entity:

(a) dividends or other distributions or payments on
capital stock or other equity interest of such corporation,
association or other business entity (except distributions in
such stock or other equity interest); and

(b) the redemption or acquisition of such stock or
other equity interests or of warrants, rights or other options
to purchase such stock or other equity interests (except when
solely in exchange for such stock or other equity interests)
unless made, contemporaneously, from the net proceeds of a
sale of such stock or other equity interests.

"SERIES A-1 BASE RATE" means 8.46%.

"SERIES A-1 INTEREST RATE" means, with respect to any fiscal
quarter of the Company, the Series A-1 Base Rate, plus the Applicable
Margin with respect to the immediately preceding fiscal quarter.

"SERIES A-2 BASE RATE" means 8.55%.

"SERIES A-2 INTEREST RATE" means, with respect to any fiscal
quarter of the Company, the Series A-2 Base Rate, plus the Applicable
Margin with respect to the immediately preceding fiscal quarter.

"SERIES A-3 BASE RATE" means 8.61%.

"SERIES A-3 INTEREST RATE" means, with respect to any fiscal
quarter of the Company, the Series A-3 Base Rate, plus the Applicable
Margin with respect to the immediately preceding fiscal quarter.

"SERIES B-1 BASE RATE" means 8.01%.

"SERIES B-1 INTEREST RATE" means, with respect to any fiscal
quarter of the Company, the Series B-1 Base Rate, plus the Applicable
Margin with respect to the immediately preceding fiscal quarter.

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

"SERIES B-2 BASE RATE" means 8.06%.

"SERIES B-2 INTEREST RATE" means, with respect to any fiscal
quarter of the Company, the Series B-2 Base Rate, plus the Applicable
Margin with respect to the immediately preceding fiscal quarter.

"SERIES B-3 BASE RATE" means 8.29%.

"SERIES B-3 INTEREST RATE" means, with respect to any fiscal
quarter of the Company, the Series B-3 Base Rate, plus the Applicable
Margin with respect to the immediately preceding fiscal quarter.

"UTILICORP" means Aquila, Inc., a Delaware corporation (f/k/a
UtiliCorp United Inc.)."

5.15 The Series A-1 Notes outstanding on the Effective Date of this
Amendment, without any further action required on the part of any other Person,
are deemed to be automatically amended to conform to, and to have the terms
provided in, Exhibit A-1 attached hereto. Existing Series A-1 Notes may, but
need not, be surrendered for replacement Notes in accordance with Section 13.2
of the Existing Note Purchase Agreement. Each Series A-1 Note issued on or after
the Effective Date of this Amendment shall be in the form of Exhibit A-1
attached hereto.

5.16 The Series A-2 Notes outstanding on the Effective Date of this
Amendment, without any further action required on the part of any other Person,
are deemed to be automatically amended to conform to and have the terms provided
in Exhibit A-2 attached hereto. Existing Series A-2 Notes may, but need not, be
surrendered for replacement Notes in accordance with Section 13.2 of the
Existing Note Purchase Agreement. Each Series A-2 Note issued on or after the
Effective Date of this Amendment shall be in the form of Exhibit A-2 attached
hereto.

5.17 The Series A-3 Notes outstanding on the Effective Date of this
Amendment, without any further action required on the part of any other Person,
are deemed to be automatically amended to conform to and have the terms provided
in Exhibit A-3 attached hereto. Existing Series A-3 Notes may, but need not, be
surrendered for replacement Notes in accordance with Section 13.2 of the
Existing Note Purchase Agreement. Each Series A-3 Note issued on or after the
Effective Date of this Amendment shall be in the form of Exhibit A-3 attached
hereto.

5.18 The Series B-1 Notes outstanding on the Effective Date of this
Amendment, without any further action required on the part of any other Person,
are deemed to be automatically amended to conform to and have the terms provided
in Exhibit B-1 attached hereto. Existing Series B-1 Notes may, but need not, be
surrendered for replacement Notes in accordance with Section 13.2 of the
Existing Note Purchase Agreement. Each Series B-1 Note issued on or after the
Effective Date of this Amendment shall be in the form of Exhibit B-1 attached
hereto.

5.19 The Series B-2 Notes outstanding on the Effective Date of this
Amendment, without any further action required on the part of any other Person,
are deemed to be automatically amended to conform to and have the terms provided
in Exhibit B-2 attached hereto. Existing Series B-2 Notes may,

but need not, be surrendered for replacement Notes in accordance with Section
13.2 of the Existing Note Purchase Agreement. Each Series B-2 Note issued on or
after the Effective Date of this Amendment shall be in the form of Exhibit B-2
attached hereto.

5.20 The Series B-3 Notes outstanding on the Effective Date of this
Amendment, without any further action required on the part of any other Person,
are deemed to be automatically amended to conform to and have the terms provided
in Exhibit B-3 attached hereto. Existing Series B-3 Notes may, but need not, be
surrendered for replacement Notes in accordance with Section 13.2 of the
Existing Note Purchase Agreement. Each Series B-3 Note issued on or after the
Effective Date of this Amendment shall be in the form of Exhibit B-3 attached
hereto.

5.21 Schedule 5.4 to the Existing Note Purchase Agreement is hereby
replaced with Schedule 5.4 hereto.

5.22 Schedule 5.15 to the Existing Note Purchase Agreement is hereby
amended to read: "Debt reflected on the balance sheet of the Company as of June
30, 2002."

5.23 For the purposes of calculating financial covenants in the
Existing Note Purchase Agreement, as amended by Amendment No. 1, for the fiscal
quarter ended June 30, 2002, the parties acknowledge and agree that the Company
may calculate such financial covenants utilizing the terms contained in
Amendment No. 1 and agree to permit retroactive application of such terms for
this limited purpose.

SECTION 6. EFFECT OF AMENDMENT.

Except as expressly provided in this Amendment, the Existing Note
Purchase Agreement and the Notes shall remain in full force and effect, without
modification or amendment. This Amendment shall be binding upon, and shall inure
to the benefit of, the successors and assigns of the parties hereto and the
holders from time to time of the Notes.

SECTION 7. SURVIVAL.

All warranties, representations, certifications and covenants made by
the Company in this Amendment or in any certificate or other instrument
delivered by the Company or on its behalf under this Amendment shall be
considered to have been relied upon by the Noteholders and shall survive the
execution of this Amendment, regardless of any investigation made by or on
behalf of any Noteholder. All statements in any such certificate or other
instrument in connection with this Amendment shall constitute warranties and
representations of the Company under this Amendment.

SECTION 8. DUPLICATE ORIGINALS; EXECUTION IN COUNTERPART.

Two or more duplicate originals of this Amendment may be signed by the
parties, each of which shall be an original but all of which together shall
constitute one and the same instrument. This Amendment may be executed in one or
more counterparts and shall be effective when at least one counterpart shall
have been executed by the Company and the Required Holders (subject to Section 3
hereof) each as a party to this Amendment, and each set of counterparts which,
collectively, show execution by each such party to this Amendment shall
constitute one duplicate original.

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

SECTION 9. GOVERNING LAW.

THIS AMENDMENT SHALL BE GOVERNED BY, AND CONSTRUED AND ENFORCED IN
ACCORDANCE WITH, NEW YORK LAW WITHOUT REGARD TO PRINCIPLES OF CONFLICTS OF LAWS.

[REMAINDER OF PAGE INTENTIONALLY BLANK. NEXT PAGE IS SIGNATURE PAGE.]

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

IN WITNESS WHEREOF, the Company and the Noteholders have executed this
Amendment as of the date first above written.

QUANTA SERVICES, INC.

By: /s/ James H. Haddox
----------------------------------
Name: James H. Haddox
Title: Chief Financial Officer

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

ACCEPTED AND AGREED TO:

MASSACHUSETTS MUTUAL LIFE INSURANCE COMPANY

By: David L. Babson and Company
Incorporated, as Investment Advisor

By: /s/ Richard C. Morrison
---------------------------------
Name: Richard C. Morrison
Title: Managing Director

C.M. LIFE INSURANCE COMPANY

By: David L. Babson and Company
Incorporated, as Investment Advisor

By: /s/ Richard C. Morrison
---------------------------------
Name: Richard C. Morrison
Title: Managing Director

UNITED OF OMAHA LIFE INSURANCE COMPANY

By: /s/ Edwin H. Garrison Jr.
---------------------------------
Name: Edwin H. Garrison Jr.
Title: First Vice President

COMPANION LIFE INSURANCE COMPANY

By: /s/ Edwin H. Garrison Jr.
---------------------------------
Name: Edwin H. Garrison Jr.
Title: Authorized Representative

NEW YORK LIFE INSURANCE AND ANNUITY CORPORATION

By: New York Life Insurance Company

By: /s/ A. Post Howland
---------------------------------
Name: A. Post Howland
Title: Vice President

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

MINNESOTA LIFE INSURANCE COMPANY

By: Advantus Capital Management, Inc.

By: /s/ Joseph Gogola
---------------------------------
Name: Joseph Gogola
Title: Vice President

AMERICAN FIDELITY ASSURANCE COMPANY

By: Advantus Capital Management, Inc.

By: /s/ James F. Geiger
---------------------------------
Name: James F. Geiger
Title: Vice President

MTL INSURANCE COMPANY

By: Advantus Capital Management, Inc.

By: /s/ David R. Hackney
---------------------------------
Name: David R. Hackney
Title: Vice President

UNITY MUTUAL LIFE INSURANCE COMPANY - ANNUITY PORTFOLIO

By: Advantus Capital Management, Inc.

By: /s/ David Land
---------------------------------
Name: David Land
Title: Vice President

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

PROTECTIVE LIFE INSURANCE COMPANY

By: /s/ Stephen M. Liberatore
-------------------------------------------
Name: Stephen M. Liberatore
Title: Vice President/Portfolio Manager

ALLSTATE LIFE INSURANCE COMPANY

By: /s/ Bill Schmidt
-------------------------------------------
Name: Bill Schmidt
Title: Authorized Signatory

By: /s/ Ronald A. Mendel
-------------------------------------------
Name: Ronald A. Mendel
Title: Authorized Signatory

AMERICAN HERITAGE LIFE INSURANCE COMPANY

By: /s/ Bill Schmidt
-------------------------------------------
Name: Bill Schmidt
Title: Authorized Signatory

By: /s/ Ronald A. Mendel
-------------------------------------------
Name: Ronald A. Mendel
Title: Authorized Signatory

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

THE TRAVELERS INSURANCE COMPANY, FOR ITSELF
AND TWO OF ITS SEPARATE ACCOUNTS

By: /s/ Robert M. Mills
---------------------------------
Name: Robert M. Mills
Title: Investment Officer

SOUTHERN FARM BUREAU LIFE INSURANCE COMPANY

By: /s/ Carol Robertson
---------------------------------
Name: Carol Robertson, CPA
Title: Portfolio Manager,
Fixed Income

COLONIAL LIFE & ACCIDENT INSURANCE COMPANY

By: Provident Investment Management, LLC, its Agent

By: /s/ David Fussell
---------------------------------
Name: David Fussell
Title: Senior Vice President

UNUM LIFE INSURANCE COMPANY OF AMERICA

By: Provident Investment Management, LLC, its Agent

By: /s/ David Fussell
---------------------------------
Name: David Fussell
Title: Senior Vice President

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

THRIVENT FINANCIAL FOR LUTHERANS (FORMERLY AID ASSOCIATION FOR LUTHERANS AND
SUCCESSOR BY MERGER TO LUTHERAN BROTHERHOOD)

By: /s/ Glen Vanic
---------------------------------
Name: Glen Vanic
Title: Portfolio Manager

PHOENIX LIFE INSURANCE COMPANY

By: /s/ John H. Beers
---------------------------------
Name: John H. Beers
Title: Vice President

GREAT-WEST LIFE & ANNUITY INSURANCE COMPANY

By: /s/ Tad Anderson
---------------------------------
Name: Tad Anderson
Title: Manager Investments

By: /s/ Mark Corbett
---------------------------------
Name: Mark Corbett
Title: Senior Vice President

MODERN WOODMEN OF AMERICA

By: /s/ Nick Coin
---------------------------------
Name: Nick Coin
Title: Treasurer & Investment
Manager

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

AMERICAN UNITED LIFE INSURANCE COMPANY

By: /s/ Christopher D. Pahlke
---------------------------------
Name: Christopher D. Pahlke
Title: Vice President

PIONEER MUTUAL LIFE INSURANCE COMPANY

By Its Agent: American United Life Insurance Company

By: /s/ Christopher D. Pahlke
---------------------------------
Name: Christopher D. Pahlke
Title: Vice President Private Placements

THE STATE LIFE INSURANCE COMPANY

By Its Agent: American United Life Insurance Company

By: /s/ Christopher D. Pahlke
---------------------------------
Name: Christopher D. Pahlke
Title: Vice President Private Placements

THE GUARDIAN LIFE INSURANCE COMPANY OF AMERICA

By: /s/ Ellen L. Whittaker
---------------------------------
Name: Ellen L. Whittaker
Title: Director

SECURITY FINANCIAL LIFE INSURANCE CO.

By: /s/ Kevin W. Hammond
---------------------------------
Name: Kevin W. Hammond
Title: Vice President Chief
Investment Officer

QUANTA SERVICES, INC. AMENDMENT NO. 1 TO NOTE PURCHASE AGREEMENT

ANNEX 1

Massachusetts Mutual Life Insurance Company
1295 State Street
Springfield, MA 01111

C.M. Life Insurance Company
1295 State Street
Springfield, MA 01111

United of Omaha Life Insurance Company
Mutual of Omaha Plaza
Omaha, NE 68175

Companion Life Insurance Company
Mutual of Omaha Plaza
Omaha, NE 68175

Minnesota Life Insurance Company
400 Robert Street North
St. Paul, MN 55101

American Fidelity Assurance Company
400 Robert Street North
St. Paul, MN 55101

MTL Insurance Company
400 Robert Street North
St. Paul, MN 55101

Unity Mutual Life Insurance Company - Annuity Portfolio
400 Robert Street North
St. Paul, MN 55101

Protective Life Insurance Company
P.O. Box 2606
Birmingham, AL 35202

Allstate Life Insurance Company
3075 Sanders Road, STE G3A
Northbrook, IL 60062-7127

American Heritage Life Insurance Company
3075 Sanders Road, STE G3A
Northbrook, IL 60062-7127

Southern Farm Bureau Life Insurance Company
1401 Livingston Lane
Jackson, MS 39213

The Travelers Insurance Company
242 Trumbull Street
P.O. Box 150449
Hartford, CT 06115-0419

The Travelers Insurance Company, for two of it's Separate Accounts
242 Trumbull Street
P.O. Box 150449
Hartford, CT 06115-0419

New York Life Insurance and Annuity Corporation
51 Madison Avenue
New York, NY 10010-1603

Thrivent Financial for Lutherans
625 Fourth Avenue South
Minneapolis, MN 55415-1624

Great-West Life & Annuity Insurance Company
8515 East Orchard Road, 3rd Floor, Tower 2
Englewood, CO 80111

Modern Woodmen of America
1701 First Avenue
Rock Island, IL 61201

The Guardian Life Insurance Company of America
700 South Street
Pittsfield, MA 01201

Colonial Life & Accident Insurance Company
One Fountain Square
Chattanooga, TN 37402

Unum Life Insurance Company of America
One Fountain Square
Chattanooga, TN 37402

Phoenix Life Insurance Company
56 Prospect Street
Hartford, CT 06115-0480

American United Life Insurance Company
One American Square
Indianapolis, IN 46206

Pioneer Mutual Life Insurance Company
One American Square
Indianapolis, IN 46206

The State Life Insurance Company
One American Square
Indianapolis, IN 46206

Security Financial Life Insurance Co.
200 Centennial Mall North
Lincoln, NE 68508

EXHIBIT A-1

[FORM OF TRANCHE 1 NOTE]

QUANTA SERVICES, INC.

SERIES 2000-A SENIOR SECURED NOTE, TRANCHE 1, DUE MARCH 1, 2005

No. [_____] [Date]
$[________] PPN [_____________]

FOR VALUE RECEIVED, the undersigned, QUANTA SERVICES, INC. (herein
called the "Company"), a corporation organized and existing under the laws of
the State of Delaware, hereby promises to pay to [_____________________] or
registered assigns, the principal sum of [__________________] DOLLARS on March
1, 2005 with interest (computed on the basis of a 360-day year of twelve 30-day
months) (a) on the unpaid balance thereof at (i) the Series A-1 Base Rate for
the period beginning on the date from which interest has most recently paid
prior to [August 12, 2002] and ending on (but not including) August 12, 2002 and
(ii) the Series A-1 Interest Rate from [August 12, 2002], in each case, payable
quarterly in arrears, on the first day of each January, April, July and October,
and at maturity, until the principal hereof shall have become due and payable,
and (b) to the extent permitted by law on any overdue payment (including any
overdue prepayment) of principal, any overdue payment of interest and any
overdue payment of any Make-Whole Amount, payable quarterly as aforesaid (or, at
the option of the registered holder hereof, on demand), at a rate per annum from
time to time equal to the greater of (i) the Series A-1 Interest Rate plus 2% or
(ii) 2% over the rate of interest publicly announced by Bank of America, N.A.
from time to time in New York, New York as its "base" or "prime" rate, but in
any event not in excess of the highest rate allowed by applicable law. If at
June 30, 2004 or any time thereafter the consolidated debt ratio measured by
Section 10.2 of the Note Purchase Agreement referred to below has been 2.5 to
1.0 or less for four consecutive fiscal quarters, interest on this Note shall
become payable semiannually on the first (1st) day of January and July of each
year.

Payments of principal of interest on and any Make-Whole Amount with
respect to this Note are to be made in lawful money of the United States of
America at the principal office of Bank of America, N.A. in New York, New York
or at such other place as the Company shall have designated by written notice to
the holder of this Note as provided in the Note Purchase Agreement referred to
below.

This Note is one of a series of Senior Secured Notes (herein called the
"Notes") issued pursuant to the Note Purchase Agreement, dated as of March 1,
2000 (as from time to time amended, supplemented or modified, the "Note Purchase
Agreement"), between the Company and the respective Purchasers named therein and
is entitled to the benefits thereof. Terms used herein and not defined shall
have the meanings ascribed to them in the Note Purchase Agreement. Each holder
of this Note will be deemed, by its acceptance hereof, (i) to have agreed to the
confidentiality provisions set forth in Section 20 of the Note Purchase
Agreement and (ii) to have made the representation set forth in Section 6.2 of
the Note Purchase Agreement.

This Note is a registered Note and, as provided in the Note Purchase
Agreement, upon surrender of this Note for registration of transfer, duly
endorsed, or accompanied by a written instrument of transfer duly executed, by
the registered holder hereof or such holder's attorney duly authorized in
writing, a new Note for a like principal amount will be issued to, and
registered in the name of, the transferee. Prior to due presentment for
registration of transfer, the Company may treat the person in whose name this
Note is registered as the owner hereof for the purpose of receiving payment and
for all other purposes, and the Company will not be affected by any notice to
the contrary.

The Company will make required prepayments of principal on the dates
and in the amounts specified in the Note Purchase Agreement. This Note is also
subject to optional and mandatory prepayment, in whole or from time to time in
part, at the times and on the terms specified in the Note Purchase Agreement,
but not otherwise.

If an Event of Default, as defined in the Note Purchase Agreement,
occurs and is continuing, the principal of this Note may be declared or
otherwise become due and payable in the manner, at the price (including any
applicable Make-Whole Amount) and with the effect provided in the Note Purchase
Agreement.

Pursuant to the Guaranty Agreement dated as of March 1, 2000, certain
subsidiaries of the Company have absolutely and unconditionally guaranteed
payment in full of the principal of, Make-Whole Amount if any, and interest on
this Note and the performance by the Company of all of its obligations contained
in the Note Purchase Agreement all as more fully set forth in said Guaranty
Agreement.

THIS NOTE SHALL BE CONSTRUED AND ENFORCED IN ACCORDANCE WITH, AND THE
RIGHTS OF THE ISSUER AND HOLDER HEREOF SHALL BE GOVERNED BY, THE LAW OF THE
STATE OF NEW YORK EXCLUDING CHOICE-OF-LAW PRINCIPLES OF THE LAW OF SUCH STATE
THAT WOULD REQUIRE THE APPLICATION OF THE LAWS OF A JURISDICTION OTHER THAN SUCH
STATE.

QUANTA SERVICES, INC.

By
----------------------------------
Name:
----------------------------
Title:
---------------------------

EXHIBIT A-2

[FORM OF TRANCHE 2 NOTE]

QUANTA SERVICES, INC.

SERIES 2000-A SENIOR SECURED NOTE, TRANCHE 2, DUE MARCH 1, 2007

No. [_____] [Date]
$[________] PPN [_____________]

FOR VALUE RECEIVED, the undersigned, QUANTA SERVICES, INC. (herein
called the "Company"), a corporation organized and existing under the laws of
the State of Delaware, hereby promises to pay to [_____________________] or
registered assigns, the principal sum of [__________________] DOLLARS on March
1, 2007 with interest (computed on the basis of a 360-day year of twelve 30-day
months) (a) on the unpaid balance thereof at (i) the Series A-2 Base Rate for
the period beginning on the date from which interest has most recently paid
prior to [August 12, 2002] and ending on (but not including) August 12, 2002 and
(ii) the Series A-2 Interest Rate from [August 12, 2002], in each case, payable
quarterly, in arrears, on the first day of each January, April, July and
October, and at maturity, until the principal hereof shall have become due and
payable, and (b) to the extent permitted by law on any overdue payment
(including any overdue prepayment) of principal, any overdue payment of interest
and any overdue payment of any Make-Whole Amount, payable quarterly as aforesaid
(or, at the option of the registered holder hereof, on demand), at a rate per
annum from time to time equal to the greater of (i) the Series A-2 Interest Rate
plus 2% or (ii) 2% over the rate of interest publicly announced by Bank of
America, N.A. from time to time in New York, New York as its "base" or "prime"
rate, but in any event not in excess of the highest allowed by applicable law.
If at June 30, 2004 or any time thereafter the consolidated debt ratio measured
by Section 10.2 of the Note Purchase Agreement referred to below has been 2.5 to
1.0 or less for four consecutive fiscal quarters, interest on this Note shall
become payable semiannually on the first (1st) day of January and July of each
year.

QUANTA SERVICES, INC.

By
----------------------------------
Name:
----------------------------
Title:
---------------------------

EXHIBIT A-3

[FORM OF TRANCHE 3 NOTE]

QUANTA SERVICES, INC.

SERIES 2000-A SENIOR SECURED NOTE, TRANCHE 3, DUE MARCH 1, 2010

No. [_____] [Date]
$[________] PPN [_____________]

FOR VALUE RECEIVED, the undersigned, QUANTA SERVICES, INC. (herein
called the "Company"), a corporation organized and existing under the laws of
the State of Delaware, hereby promises to pay to [_____________________] or
registered assigns, the principal sum of [__________________] DOLLARS on March
1, 2010 with interest (computed on the basis of a 360-day year of twelve 30-day
months) (a) on the unpaid balance thereof at (i) the Series A-3 Base Rate for
the period beginning on the date from which interest has most recently paid
prior to [August 12, 2002] and ending on (but not including) August 12, 2002 and
(ii) the Series A-3 Interest Rate from [August 12, 2002], in each case, payable
quarterly in arrears, on the first day of each January, April, July and October,
and at maturity, until the principal hereof shall have become due and payable,
and (b) to the extent permitted by law on any overdue payment (including any
overdue prepayment) of principal, any overdue payment of interest and any
overdue payment of any Make-Whole Amount, payable quarterly as aforesaid (or, at
the option of the registered holder hereof, on demand), at a rate per annum from
time to time equal to the greater of (i) the Series A-3 Interest Rate plus 2% or
(ii) 2% over the rate of interest publicly announced by Bank of America, N.A.
from time to time in New York, New York as its "base" or "prime" rate, but in
any event not in excess of the highest rate allowed by applicable law. If at
June 30, 2004 or any time thereafter the consolidated debt ratio measured by
Section 10.2 of the Note Purchase Agreement referred to below has been 2.5 to
1.0 or less for four consecutive fiscal quarters, interest on this Note shall
become payable semiannually on the first (1st) day of January and July of each
year.

QUANTA SERVICES, INC.

By
----------------------------------
Name:
----------------------------
Title:
---------------------------

EXHIBIT B-1

[FORM OF SERIES 2000-B, TRANCHE 1 NOTES]

QUANTA SERVICES, INC.

SERIES 2000-B SENIOR SECURED NOTE, TRANCHE 1, DUE SEPTEMBER 1, 2005

No. [_____] [Date]
$[________] PPN [_____________]

FOR VALUE RECEIVED, the undersigned, QUANTA SERVICES, INC. (herein
called the "Company"), a corporation organized and existing under the laws of
the State of Delaware, hereby promises to pay to [_____________________] or
registered assigns, the principal sum of [__________________] DOLLARS on
September 1, 2005 with interest (computed on the basis of a 360-day year of
twelve 30-day months) (a) on the unpaid balance thereof at (i) the Series B-1
Base Rate for the period beginning on the date from which interest has most
recently paid prior to [August 12, 2002] and ending on (but not including)
August 12, 2002 and (ii) the Series B-1 Interest Rate from [August 12, 2002], in
each case, payable quarterly in arrears, on the first day of each January,
April, July and October, and at maturity, until the principal hereof shall have
become due and payable, and (b) to the extent permitted by law on any overdue
payment (including any overdue prepayment) of principal, any overdue payment of
interest and any overdue payment of any Make-Whole Amount, payable quarterly as
aforesaid (or, at the option of the registered holder hereof, on demand), at a
rate per annum from time to time equal to the greater of (i) the Series B-1
Interest Rate plus 2% or (ii) 2% over the rate of interest publicly announced by
Bank of America, N.A. from time to time in New York, New York as its "base" or
"prime" rate, but in any event not in excess of the highest rate allowed by
applicable law. If at June 30, 2004 or any time thereafter the consolidated debt
ratio measured by Section 10.2 of the Note Purchase Agreement referred to below
has been 2.5 to 1.0 or less for four consecutive fiscal quarters, interest on
this Note shall become payable semiannually on the first (1st) day of January
and July of each year.

This Note is one of a series of Senior Secured Notes (herein called the
"Notes") issued pursuant to the Note Purchase Agreement, dated as of March 1,
2000 (as from time to time amended, supplemented or modified, the "Note Purchase
Agreement"), between the Company, the Purchasers named therein and Additional
Purchases of Notes from time to time issued pursuant to any Supplement to the
Note Purchase Agreement. This Note and the holder hereof are entitled equally
and ratably with the holders of all other Notes of all series from time to time
outstanding under the Note Purchase Agreement to all the benefits provided for
thereby or referred to therein. Terms used herein and not defined shall have the
meanings ascribed to them in the Note Purchase Agreement. Each holder of this
Note will be deemed, by its acceptance hereof, (i) to have agreed to the
confidentiality provisions set forth in Section 20 of the Note

Purchase Agreement and (ii) to have made the representation set forth in Section
6.2 of the Note Purchase Agreement, provided that such holder may (in reliance
upon information provided by the Company, which shall not be unreasonably
withheld) make a representation to the effect that the purchase by such holder
of any Note will not constitute a non-exempt prohibited transaction under
Section 406(a) of ERISA.

This Note is registered with the Company and, as provided in the Note
Purchase Agreement, upon surrender of this Note for registration of transfer,
duly endorsed, or accompanied by a written instrument of transfer duly executed,
by the registered holder hereof or such holder's attorney duly authorized in
writing, a new Note of the same series for a like principal amount will be
issued to, and registered in the name of, the transferee. Prior to due
presentment for registration of transfer, the Company may treat the person in
whose name this Note is registered as the owner hereof for the purpose of
receiving payment and for all other purposes, and the Company will not be
affected by any notice tot he contrary.

This Note is not subject to regularly scheduled prepayments of
principal. This Note is subject to optional and mandatory prepayment, in whole
or from time to time in part, at the times and on the terms specified in the
Note Purchase Agreement, but not otherwise.

QUANTA SERVICES, INC.

By
----------------------------------
Name:
----------------------------
Title:
---------------------------

EXHIBIT B-2

[FORM OF SERIES 2000-B, TRANCHE 2 NOTES]

QUANTA SERVICES, INC.

SERIES 2000-B SENIOR SECURED NOTE, TRANCHE 2, DUE SEPTEMBER 1, 2006

No. [_____] [Date]
$[________] PPN [_____________]

FOR VALUE RECEIVED, the undersigned, QUANTA SERVICES, INC. (herein
called the "Company"), a corporation organized and existing under the laws of
the State of Delaware, hereby promises to pay to [_____________________] or
registered assigns, the principal sum of [__________________] DOLLARS on
September 1, 2006 with interest (computed on the basis of a 360-day year of
twelve 30-day months) (a) on the unpaid balance thereof at (i) the Series B-2
Base Rate for the period beginning on the date from which interest has most
recently paid prior to [August 12, 2002] and ending on (but not including)
August 12, 2002 and (ii) the Series B-2 Interest Rate from [August 12, 2002], in
each case, payable quarterly in arrears, on the first day of each January,
April, July and October, and at maturity, until the principal hereof shall have
become due and payable, and (b) to the extent permitted by law on any overdue
payment (including any overdue prepayment) of principal, any overdue payment of
interest and any overdue payment of any Make-Whole Amount, payable quarterly as
aforesaid (or, at the option of the registered holder hereof, on demand), at a
rate per annum from time to time equal to the greater of (i) the Series B-2
Interest Rate plus 2% or (ii) 2% over the rate of interest publicly announced by
Bank of America, N.A. from time to time in New York, New York as its "base" or
"prime" rate, but in any event not in excess of the highest rate allowed by
applicable law. If at June 30, 2004 or any time thereafter the consolidated debt
ratio measured by Section 10.2 of the Note Purchase Agreement referred to below
has been 2.5 to 1.0 or less for four consecutive fiscal quarters, interest on
this Note shall become payable semiannually on the first (1st) day of January
and July of each year.

This Note is one of a series of Senior Secured Notes (herein called the
"Notes") issued pursuant to the Note Purchase Agreement, dated as of March 1,
2000 (as from time to time amended, supplemented or modified, the "Note Purchase
Agreement"), between the Company, the Purchasers named therein and Additional
Purchases of Notes from time to time issued pursuant to any Supplement to the
Note Purchase Agreement. This Note and the holder hereof are entitled equally
and ratably with the holders of all other Notes of all series from time to time
outstanding under the Note Purchase Agreement to all the benefits provided for
thereby or referred to therein. Terms used herein and not defined shall have the
meanings ascribed to them in the Note Purchase Agreement. Each holder of this
Note will be deemed, by its acceptance

hereof, (i) to have agreed to the confidentiality provisions set forth in
Section 20 of the Note Purchase Agreement and (ii) to have made the
representation set forth in Section 6.2 of the Note Purchase Agreement, provided
that such holder may (in reliance upon information provided by the Company,
which shall not be unreasonably withheld) make a representation to the effect
that the purchase by such holder of any Note will not constitute a non-exempt
prohibited transaction under Section 406(a) of ERISA.

QUANTA SERVICES, INC.

By
----------------------------------
Name:
----------------------------
Title:
---------------------------

EXHIBIT B-3

[FORM OF SERIES 2000-B, TRANCHE 3 NOTES]

QUANTA SERVICES, INC.

SERIES 2000-B SENIOR SECURED NOTE, TRANCHE 3, DUE SEPTEMBER 1, 2010

No. [_____] [Date]
$[________] PPN [_____________]

FOR VALUE RECEIVED, the undersigned, QUANTA SERVICES, INC. (herein
called the "Company"), a corporation organized and existing under the laws of
the State of Delaware, hereby promises to pay to [_____________________] or
registered assigns, the principal sum of [__________________] DOLLARS on
September 1, 2010 with interest (computed on the basis of a 360-day year of
twelve 30-day months) (a) on the unpaid balance thereof at (i) the Series B-3
Base Rate for the period beginning on the date from which interest has most
recently paid prior to [August 12, 2002] and ending on (but not including)
August 12, 2002 and (ii) the Series B-3 Interest Rate from [August 12, 2002], in
each case, payable quarterly in arrears, on the first day of each January,
April, July and October, and at maturity, until the principal hereof shall have
become due and payable, and (b) to the extent permitted by law on any overdue
payment (including any overdue prepayment) of principal, any overdue payment of
interest and any overdue payment of any Make-Whole Amount, payable quarterly as
aforesaid (or, at the option of the registered holder hereof, on demand), at a
rate per annum from time to time equal to the greater of (i) the Series B-3
Interest Rate plus 2% or (ii) 2% over the rate of interest publicly announced by
Bank of America, N.A. from time to time in New York, New York as its "base" or
"prime" rate, but in any event not in excess of the highest rate allowed by
applicable law. If at June 30, 2004 or any time thereafter the consolidated debt
ratio measured by Section 10.2 of the Note Purchase Agreement referred to below
has been 2.5 to 1.0 or less for four consecutive fiscal quarters, interest on
this Note shall become payable semiannually on the first (1st) day of January
and July of each year.

This Note is one of a series of Senior Secured Notes (herein called the
"Notes") issued pursuant to the Note Purchase Agreement, dated as of March 1,
2000 (as from time to time amended, supplemented or modified, the "Note Purchase
Agreement"), between the Company, the Purchasers named therein and Additional
Purchases of Notes from time to time issued pursuant to any Supplement to the
Note Purchase Agreement. This Note and the holder hereof are entitled equally
and ratably with the holders of all other Notes of all series from time to time
outstanding under the Note Purchase Agreement to all the benefits provided for
thereby or referred to therein. Terms used herein and not defined shall have the
meanings ascribed to them in the Note Purchase Agreement. Each holder of this
Note will be deemed, by its acceptance hereof, (i) to have agreed to the
confidentiality provisions set forth in Section 20 of the Note Purchase
Agreement

and (ii) to have made the representation set forth in Section 6.2 of the Note
Purchase Agreement, provided that such holder may (in reliance upon information
provided by the Company, which shall not be unreasonably withheld) make a
representation to the effect that the purchase by such holder of any Note will
not constitute a non-exempt prohibited transaction under Section 406(a) of
ERISA.

QUANTA SERVICES, INC.

By
----------------------------------
Name:
----------------------------
Title:
---------------------------

SCHEDULE 5.4

<Table>
<Caption>
SUBSIDIARY STATE OF INCORPORATION STOCKHOLDER
- ---------- ---------------------- -----------

Advanced Technologies and Installation Corporation Washington Quanta Services, Inc.
Airlan Telecom Services, L.P. Texas
Allteck Line Contractors (USA), Inc. Washington Quanta Services, Inc.
Allteck Line Contractors, Inc. British Columbia
Arby Construction, Inc. Delaware Quanta Services, Inc.
Austin Trencher, Inc. Delaware Quanta Services, Inc.
Bradford Brothers, Inc. North Carolina Quanta Services, Inc.
Brown Engineering, LLC Delaware Spalj Construction Company
CCLC, Inc. Delaware Conti Communications, Inc.
Coast to Coast, LLC California Environmental Professional
Associates, Limited
Communication Manpower, Inc. Florida Trawick Construction Company, Inc.
Computapole, Inc. Delaware Quanta Services, Inc.
Conti Communications, Inc. Delaware Quanta Services, Inc.
Croce Electric Company, Inc. Delaware Quanta Services, Inc.
Crown Fiber Communications, Inc. Virginia Quanta Services, Inc.
Digco Utility Construction, L.P. Delaware Mejia Personnel Services, Inc.
QDE LLC
Dillard Smith Construction Company Delaware Quanta Services, Inc.
Dot 05, LLC Delaware Spalj Construction Company
Driftwood Electrical Contractors, Inc. Delaware Quanta Services, Inc.
Environmental Professional Associates, Limited California Quanta Services, Inc.
Five Points Construction Co. Texas Underground Construction Co., Inc.
GEM Engineering Co., Inc. Delaware Quanta Services, Inc.
Golden State Utility Co. Delaware Quanta Services, Inc.
H.L. Chapman Pipeline Construction, Inc. Delaware Quanta Services, Inc.
Haines Construction Company Delaware Quanta Services, Inc.
Intermountain Electric, Inc. Colorado Quanta Services, Inc.
Irby Construction Company Mississippi Quanta Services, Inc.
Lake Norman Pipeline, LLC North Carolina Bradford Brother, Incorporated
Lindsey Electric, L.P. Delaware Mejia Personnel Services, Inc.
North Houston Pole Line, L.P.
Lineco Leasing, LLC Washington Mustang Line Contractors, Inc.
Line Equipment Sales Co., Inc. South Carolina Sumter Utilities, Inc.
Logical Link, Inc. Delaware Quanta Services, Inc.
Manuel Bros., Inc. Delaware Quanta Services, Inc.
Mears Engineering, LLC Michigan Mears Group, Inc.
Mears Group, Inc. Delaware Quanta Services, Inc.
Mears Services, LLC Michigan Mears Group, Inc.
Mears/CPG, LLC Michigan Mears Group, Inc.
Mears/HDD, LLC Michigan Mears Group, Inc.
Mearsmex S. de R.L. de C.V. Mexico Mears Group, Inc.
Mears/HDD, LLC
Mejia Personnel Services, Inc. Texas Quanta Services, Inc.
Metro Underground Services, Inc. Illinois Quanta Services, Inc.
Mustang Line Contractors, Inc. Washington Quanta Services, Inc.
Network Communication Services, Inc. Delaware Quanta Services, Inc.
</Table>

<Table>
<Caption>
SUBSIDIARY STATE OF INCORPORATION STOCKHOLDER
- ---------- ---------------------- -----------

Network Electric Company Delaware Quanta Services, Inc.
North Houston Pole Line, L.P. Texas Mejia Personnel Services, Inc.
QDE LLC
North Pacific Construction Co., Inc. Delaware Quanta Services, Inc.
North Sky Communications, Inc. Delaware Quanta Services, Inc.
Northern Line Layers, Inc. Delaware Quanta Services, Inc.
Okay Construction Company, LLC Delaware Spalj Construction Company
P.D.G. Electric Company Florida Quanta Services, Inc.
Pac West Construction, Inc. Delaware Quanta Services, Inc.
PAR Electrical Contractors, Inc. Missouri Quanta Services, Inc.
Parkside Site & Utility Company Corporation Delaware Quanta Services, Inc.
Parkside Utility Construction Corp. Delaware Quanta Services, Inc.
Potelco, Inc. Washington Quanta Services, Inc.
Professional Teleconcepts, Inc. Illinois Quanta Services, Inc.
Professional Teleconcepts, Inc. New York Quanta Services, Inc.
PWR Financial Company Delaware Quanta Services, Inc.
PWR Network, LLC Delaware PWR Financial Company
Q Resources, LLC Delaware Quanta Holdings, Inc.
QDE LLC Delaware PWR Financial Company
QPC, Inc. Delaware Quanta Services, Inc.
QSI, Inc. Delaware Quanta Holdings, Inc.
Quanta Asset Management LLC Delaware QSI, Inc.
Quanta Associates, L.P. Delaware Quanta Asset Management LLC
QSI, Inc.
Quanta Delaware, Inc. Delaware Quanta Holdings, Inc.
Quanta Holdings, Inc. Delaware Quanta Services, Inc.
Quanta LI Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta LIV Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta LIX Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta LVII Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta LVIII Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta LX Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta LXI Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta LXII Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta LXIII Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta LXIV Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta LXIX Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta LXV Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta LXVI Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta LXVII Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta LXVIII Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta LXX Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta LXXI Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta LXXII Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta LXXIII Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta XXXI Acquisition, Inc. Delaware Quanta Services, Inc.
Quanta Receivables, L.P. Delaware QDE LLC
PWR Network, LLC
Quanta Services of Canada Ltd. British Columbia Quanta Services, Inc.
Quanta Services Management Partnership, L.P. Texas Quanta Delaware, Inc.
QSI, Inc.
Quanta Utility Installation Company, Inc. Delaware Quanta Services, Inc.
</Table>

<Table>
<Caption>
SUBSIDIARY STATE OF INCORPORATION STOCKHOLDER
- ---------- ---------------------- -----------

R.A. Waffensmith & Co., Inc. Delaware Quanta Services, Inc.
Ranger Field Services, Inc. Delaware Quanta Services, Inc.
S.K.S. Pipeliners, LLC Delaware Arby Construction, Inc.
Southeast Pipeline Construction, Inc. Delaware Quanta Services, Inc.
Southwestern Communications, Inc. Delaware Quanta Services, Inc.
Southwest Trenching Company, Inc. Texas Quanta Services, Inc.
Spalj Construction Company Delaware Quanta Services, Inc.
Specialty Drilling Technology, Inc. Delaware Quanta Services, Inc.
Sumter Utilities, Inc. Delaware Quanta Services, Inc.
The Ryan Company, Inc. Massachusetts Quanta Services, Inc.
Tjader, L.L.C. Delaware Spalj Construction Company
TNS-VA, LLC Delaware Professional Teleconcepts, Inc.
Tom Allen Construction Company Delaware Quanta Services, Inc.
Trans Tech Acquisition, Inc. Texas Quanta Services, Inc.
Trans Tech Electric, L.P. Texas TTLP, Inc.
TTGP, Inc.
Trawick Construction Company, Inc. Florida Quanta Services, Inc.
TTGP, Inc. Delaware Quanta Services, Inc.
TTLP, Inc. Delaware Quanta Services, Inc.
TTM, Inc. North Carolina Quanta Services, Inc.
TXLP, Inc. Delaware Quanta Services, Inc.
Underground Construction Co., Inc. Delaware Quanta Services, Inc.
Utilco, Inc. Georgia Quanta Services, Inc.
VCI Telcom, Inc. Delaware Quanta Services, Inc.
W. C. Communications, Inc. Delaware Quanta Services, Inc.
W.H.O.M. Corporation California Quanta Services, Inc.
</Table>

The Company's directors are James R. Ball, John R. Colson, Terrence P.
Dunn, Vincent D. Foster, Louis C. Golm, Robert K. Green, Keith G. Stamm, Gary A.
Tucci, and John R. Wilson.

The Company's executive officers are John R. Colson, Peter Dameris,
Dana A. Gordon, Nick Grindstaff, Frederick M. Haag, James H. Haddox, Derrick A.
Jensen, James F. O'Neil, III, Elliott C. Robbins, Gary W. Smith, Luke T. Spalj
and John R. Wilson.

ATTACHMENT A

QUANTA SERVICES, INC.

OFFICERS' CERTIFICATE

We, [__________] and [_________], hereby certify that we are the duly
elected, qualified and acting [President/Vice President] and
[Secretary/Assistant Secretary] of QUANTA SERVICES, INC., a Delaware corporation
(the "COMPANY"), and that, as such, we have access to its records and are
familiar with the matters herein certified, and we are authorized to execute and
deliver this certificate in the name and on behalf of the Company, and further
certify as follows.

1. This certificate is being delivered pursuant to Section 3(g) of
Amendment No. 1 to Note Purchase Agreement (the "AMENDMENT"), dated as of August
12, 2002, entered into by the Company and each of the purchasers listed on the
signature pages thereto (together with any affiliates thereof, the
"NOTEHOLDERS"). The terms used in this certificate and not defined herein have
the respective meanings specified in the Amendment.

2. Attached hereto as Attachment A is a true and correct copy of
resolutions adopted by the Board of Directors of the Company, and such
resolutions set forth in Attachment A hereto were duly adopted by said Board of
Directors and are in full force and effect on and as of the date hereof, not
having been amended, altered or repealed, and such resolutions are filed with
the records of the Board of Directors.

3. The documents listed below were executed and delivered by the
Company pursuant to and in accordance with the resolutions set forth in
Attachment A hereto:

(i) Amendment No. 1 to Note Purchase Agreement.

4. Attached hereto as Attachment B is a true, correct and complete copy
of the Articles of Incorporation and By-laws of the Company as in full force and
effect on and as of the date hereof without modification or amendment in any
respect.

5. Each of the officers of the Company listed on Attachment C has been
a duly elected, qualified and acting officer of the Company holding the office
or offices set forth below opposite his or her name and the signature appearing
opposite the name of each such person on Attachment C is his or her genuine
signature.

6. Attached hereto as Attachment D is a good standing certificate in
respect of the Company from the State of Delaware.

IN WITNESS THEREOF, We have hereunto set our hands on August 12 2002.

QUANTA SERVICES, INC.

By:
------------------------------
Name:
Title:

ATTACHMENT A

BOARD OF DIRECTORS
QUANTA SERVICES, INC.
RESOLUTIONS ADOPTED

ATTACHMENT B

ARTICLES OF INCORPORATION AND BYLAWS OF THE COMPANY

ATTACHMENT C

SPECIMEN SIGNATURES OF OFFICERS EXECUTING DOCUMENTS

<Table>
<Caption>
NAME TITLE(s) SIGNATURE
- ---- -------- ---------

- ---------- ---------- ------------------------

- ---------- ----------
------------------------

- ---------- ----------
------------------------
</Table>

ATTACHMENT D

GOOD STANDING CERTIFICATE OF THE COMPANY

ATTACHMENT B

CONSENT OF GUARANTORS

The undersigned Guarantors, as party to the Guaranty Agreement dated as
of March 1, 2000, hereby consent to the foregoing Amendment dated as of even
date herewith, to which this consent is attached, and confirm that the Guaranty
Agreement remains in full force and effect after giving effect thereto and
represent and warrant that there is no defense, counterclaim or offset of any
type or nature under the Guaranty Agreement.

Dated as of August 12, 2002

GUARANTORS:

ADVANCED TECHNOLOGIES AND INSTALLATION
CORPORATION
ALLTECK LINE CONTRACTORS (USA), INC.
ARBY CONSTRUCTION, INC.
AUSTIN TRENCHER, INC.
BRADFORD BROTHERS, INC.
CCLC, INC.
COMMUNICATION MANPOWER, INC.
COMPUTAPOLE, INC.
CONTI COMMUNICATIONS, INC.
CROCE ELECTRIC COMPANY, INC.
CROWN FIBER COMMUNICATIONS, INC.
DILLARD SMITH CONSTRUCTION COMPANY
DRIFTWOOD ELECTRICAL CONTRACTORS, INC.
ENVIRONMENTAL PROFESSIONAL ASSOCIATES, LIMITED
FIVE POINTS CONSTRUCTION CO.
GEM ENGINEERING CO., INC.
GOLDEN STATE UTILITY CO.
H.L. CHAPMAN PIPELINE CONSTRUCTION, INC.
HAINES CONSTRUCTION COMPANY
INTERMOUNTAIN ELECTRIC, INC.
IRBY CONSTRUCTION COMPANY
LINE EQUIPMENT SALES CO., INC.
LOGICAL LINK, INC.
MANUEL BROS., INC.
MEARS GROUP, INC.
MEJIA PERSONNEL SERVICES, INC.
METRO UNDERGROUND SERVICES, INC.
MUSTANG LINE CONTRACTORS, INC.
NETWORK COMMUNICATION SERVICES, INC.
NETWORK ELECTRIC COMPANY
NORTH PACIFIC CONSTRUCTION CO., INC.
NORTH SKY COMMUNICATIONS, INC.
NORTHERN LINE LAYERS, INC.

PAC WEST CONSTRUCTION, INC.
PAR ELECTRICAL CONTRACTORS, INC.
PARKSIDE SITE & UTILITY COMPANY CORPORATION
PARKSIDE UTILITY CONSTRUCTION CORP.
P.D.G. ELECTRIC COMPANY
POTELCO, INC.
PROFESSIONAL TELECONCEPTS, INC. (IL)
PROFESSIONAL TELECONCEPTS, INC. (NY)
PWR FINANCIAL COMPANY
QPC, INC.
QSI, INC.
QUANTA HOLDINGS, INC.
QUANTA XXXI ACQUISITION, INC.
QUANTA LI ACQUISITION, INC.
QUANTA LIV ACQUISITION, INC.
QUANTA LVII ACQUISITION, INC.
QUANTA LVIII ACQUISITION, INC.
QUANTA LIX ACQUISITION, INC.
QUANTA LX ACQUISITION, INC.
QUANTA LXI ACQUISITION, INC.
QUANTA LXII ACQUISITION, INC.
QUANTA LXIII ACQUISITION, INC.
QUANTA LXIV ACQUISITION, INC.
QUANTA LXV ACQUISITION, INC.
QUANTA LXVI ACQUISITION, INC.
QUANTA LXVII ACQUISITION, INC.
QUANTA LXVIII ACQUISITION, INC.
QUANTA LXIX ACQUISITION, INC.
QUANTA LXX ACQUISITION, INC.
QUANTA LXXI ACQUISITION, INC.
QUANTA LXXII ACQUISITION, INC.
QUANTA LXXIII ACQUISITION, INC.
QUANTA UTILITY INSTALLATION CO., INC.
R.A. WAFFENSMITH & CO., INC.
RANGER FIELD SERVICES, INC.
SOUTHEAST PIPELINE CONSTRUCTION, INC.
SOUTHWEST TRENCHING COMPANY, INC.
SOUTHWESTERN COMMUNICATIONS, INC.
SPALJ CONSTRUCTION COMPANY
SPECIALTY DRILLING TECHNOLOGY, INC.
SUMTER UTILITIES, INC.
THE RYAN COMPANY, INC.
TOM ALLEN CONSTRUCTION COMPANY
TRANS TECH ACQUISITION, INC.
TRAWICK CONSTRUCTION COMPANY, INC.
TTGP, INC.
TTLP. INC.
TTM, INC.
TXLP, INC.
UNDERGROUND CONSTRUCTION CO., INC.

UTILCO, INC.
VCI TELECOM, INC.
W.C. COMMUNICATIONS, INC.
W.H.O.M. CORPORATION

By:
-----------------------------------------
Name: Dana Gordon
Title: President or Vice-President of
each Guarantor

QDE LLC
QUANTA DELAWARE, INC.
QUANTA ASSET MANAGEMENT LLC

By:
------------------------------------
Name: Linda Bubacz
Title: President

BROWN ENGINEERING, LLC

By: Ranger Field Services, Inc., Its
Member

By:
------------------------------------
Name: Dana Gordon
Title: Vice President

COAST TO COAST, LLC

By: Environmental Professional
Associates, Limited, Its Member

By:
------------------------------------
Name: Dana Gordon
Title: Vice President

DOT 05, LLC
TJADER, L.L.C.
OKAY CONSTRUCTION COMPANY, LLC

By: Spalj Construction Company, Its
Member

By:
------------------------------------
Name: Dana Gordon
Title: Vice President

LAKE NORMAN PIPELINE, LLC

By: Bradford Brothers, Inc., Its Member

By:
------------------------------------
Name: Dana Gordon
Title: Vice President

MEARS/CPG, LLC
MEARS ENGINEERING, LLC
MEARS/HDD, LLC
MEARS SERVICES, LLC

By: Mears Group, Inc., The Sole Member
of each of the foregoing limited
liability companies

By:
------------------------------------
Name: Dana Gordon
Title: Vice President

S.K.S. PIPELINERS, LLC

By: Arby Construction, Inc., Its Member

By:
------------------------------------
Name: Dana Gordon
Title: Vice President

TNS-VA, LLC

By: Professional Teleconcepts, Inc.
(NY), Its Member

By:
------------------------------------
Name: Dana Gordon
Title: Vice President

LINECO LEASING, LLC

By: Mustang Line Contractors, Inc., Its
Sole Member

By:
------------------------------------
Name: Dana Gordon
Title: Vice President

AIRLAN TELECOM SERVICES, L.P.
NORTH HOUSTON POLE LINE, L.P.
LINDSEY ELECTRIC, L.P.
DIGCO UTILITY CONSTRUCTION, L.P.

By: Mejia Personnel Services, Inc., Its
General Partner

By:
------------------------------------
Name: Dana Gordon
Title: Vice President

QUANTA SERVICES MANAGEMENT PARTNERSHIP,
L.P. QUANTA ASSOCIATES, L.P.

By: QSI, Inc., Its General Partner

By:
------------------------------------
Name: Dana Gordon
Title: Vice President

TRANS TECH ELECTRIC, L.P.

By: TTGP, Inc., Its General Partner

By:
------------------------------------
Name: Dana Gordon
Title: Vice President

PWR NETWORK, LLC

By: PWR Financial Company, Its Sole
Member

By:
------------------------------------
Name: Dana Gordon
Title: Vice President

Q RESOURCES, LLC

By: Quanta Holdings, Inc., Its Member

By:
------------------------------------
Name: Dana Gordon
Title: Vice President

QUANTA RECEIVABLES, L.P.

By: PWR Network, LLC, Its General
Partner

By: PWR Financial Company, Its Sole
Member

By:
------------------------------------
Name: Dana Gordon
Title: Vice President