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                                                                   EXHIBIT 4 (b)

                                    TXU CORP.

                              OFFICER'S CERTIFICATE

          Kirk R. Oliver, the Treasurer of TXU Corp. (the "Company"), pursuant
to the authority granted in the Board Resolutions of the Company dated February
15, 2002 and May 30, 2002 and Sections 201, 301 and 1501 of the Indenture
defined herein, does hereby certify to The Bank of New York (the "Trustee"), as
Trustee under the Indenture (For Unsecured Debt Securities Series M) of the
Company dated as of June 1, 2002 (the "Indenture") that:

1.        The securities of the first series to be issued under the Indenture
          shall be designated "Series M Senior Notes due May 16, 2008" (the
          "Series M Notes"). All capitalized terms used in this certificate
          which are not defined herein shall have the meanings set forth in the
          Indenture.

2.        The Series M Notes shall mature and the principal shall be due and
          payable together with all accrued and unpaid interest thereon on May
          16, 2008.

3.        The Series M Notes shall be issued in the denominations of $50 and
          integral multiples thereof.

4.        The Series M Notes shall bear interest initially at the rate of 5.8%
          per annum payable as follows: (a) quarterly in arrears on (i) February
          16, May 16, August 16 and November 16 of each year commencing August
          16, 2002, and (ii) the Initial Reset Date (as defined below) if the
          remarketing of the Series M Notes on the third Business Day
          immediately preceding the Initial Reset Date is successful and the
          Initial Reset Date is not November 16, 2005 or February 16, 2006; and
          (b) semi-annually in arrears on each May 16 and November 16 after the
          Initial Reset Date, or May 16, 2006, if the interest rate on the
          Series M Notes is not reset on the Initial Reset Date (each, an
          "Interest Payment Date"). The "Initial Reset Date" means any Business
          Day, as selected by the Company in its sole discretion, from November
          16, 2005 to February 16, 2006.

          The amount of interest payable on the Series M Notes will be computed
          on the basis of a 360-day year of twelve 30-day months. The amount of
          interest payable for any period shorter than a full quarterly or
          semi-annual period for which interest is computed shall be computed on
          the basis of the number of days in such period using 30 day calendar
          months. Interest on the Series M Notes will accrue from the date of
          original issuance, but if interest has been paid on such Series M
          Notes, then from the most recent Interest Payment Date to which
          interest has been paid or duly provided for. In the event that any
          Interest Payment Date is not a Business Day, then payment of interest
          payable on such date will be made on the next succeeding day which is
          a Business Day (and without any interest or other payment in respect
          of such delay), except that, if such Business Day is in the next
          succeeding calendar year, then such payment shall be made on the
          immediately

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          preceding Business Day, in each case, with the same force and effect
          as if made on such Interest Payment Date.

          The interest rate on the Series M Notes that remain Outstanding on and
          after the Initial Reset Date, or if the remarketing of the Series M
          Notes on the third Business Day immediately preceding the Initial
          Reset Date results in a Failed Remarketing (as defined herein), on and
          after May 16, 2006 (either such date, the "Reset Date"), will be reset
          to the reset rate (the "Reset Rate") determined by a Reset Agent
          appointed by the Company (the "Reset Agent") on the third Business Day
          immediately preceding either the Initial Reset Date or May 16, 2006,
          as the case may be, in the manner described below. From and after the
          Reset Date, the Series M Notes will bear interest at the Reset Rate;
          provided, that if the interest rate is not reset as a result of a
          Failed Remarketing (as defined herein) three Business Days prior to
          the Initial Reset Date, the Series M Notes will continue to bear
          interest at the initial interest rate to, but excluding, May 16, 2006.

          On the seventh Business Day immediately preceding the Reset Date, the
          Reset Agent will select the Applicable Benchmark Treasury (as defined
          herein) and determine the spread (the "Reset Spread") to be added to
          the yield on the Applicable Benchmark Treasury in order to determine
          the Reset Rate.

          If the Reset Date is the Initial Reset Date, the Reset Agent will
          determine the Reset Spread, which in the opinion of the Reset Agent,
          when added to the yield on the Applicable Benchmark Treasury on the
          third Business Day immediately preceding the Initial Reset Date, will
          equal the rate the Series M Notes should bear in order for the Series
          M Notes to have an approximate market value on such date of 100.5% of
          the Remarketing Treasury Portfolio Purchase Price (as defined herein).
          If May 16, 2006 is the Reset Date, the Reset Agent will determine the
          Reset Spread which, in the opinion of the Reset Agent, when added to
          the yield on the Applicable Benchmark Treasury on the third Business
          Day immediately preceding May 16, 2006, will equal the rate the Series
          M Notes should bear in order for each Series M Note to have an
          approximate market value on May 16, 2006 of 100.5% of the principal
          amount of such Series M Note; provided, in each case, that the Company
          may limit the Reset Rate to no higher than 200 basis points (2%) over
          the Applicable Benchmark Treasury on such Business Day, such market
          value may be less than 100.5% if the Company exercises such right to
          limit the Reset Rate and the Reset Rate shall in no event exceed the
          maximum rate permitted by applicable law.

          The "Applicable Benchmark Treasury" on a particular determination date
          means direct obligations of the United States (which may be
          obligations traded on a when-issued basis only), having a maturity
          comparable to the remaining term to maturity of the Series M Notes,
          which will be two years or between two and one-quarter years and two
          and one-half years, as applicable, as agreed upon by the Company and
          the Reset Agent. The yield for the Applicable Benchmark Treasury will
          be the bid side yield displayed at 10:00 A.M., New York City time, on
          the third Business Day immediately preceding the applicable Reset Date
          in the Telerate system (or if the Telerate system is (i) no longer
          available on the third Business Day immediately preceding the
          applicable Reset Date or (ii) in the opinion of the Reset Agent (after
          consultation with the Company), no longer an appropriate system from
          which to obtain the yield, such other nationally recognized

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          quotation system as, in the opinion of the Reset Agent (after
          consultation with the Company), is appropriate). If such yield is not
          so displayed, the yield for the Applicable Benchmark Treasury shall
          be, as calculated by the Reset Agent, the yield to maturity for the
          Applicable Benchmark Treasury, expressed as a bond equivalent on the
          basis of a year of 365 or 366 days, as applicable, and applied on a
          daily basis, and computed by taking the arithmetic mean of the
          secondary market bid yields, as of 10:30 A.M., New York City time, on
          the third Business Day immediately preceding the applicable Reset
          Date, of three leading United States government securities dealers
          selected by the Reset Agent (after consultation with the Company)
          (which may include the Reset Agent or an affiliate thereof).

          The Reset Spread and the Applicable Benchmark Treasury will be
          announced by the Company on the date they are established (each, a
          "Reset Announcement Date"), and the Company will cause a notice of the
          Reset Spread and the Applicable Benchmark Treasury to be published on
          the Business Day following the Reset Announcement Date by publication
          in a daily newspaper in the English language of general circulation in
          the City of New York, which is expected to be The Wall Street Journal.

          Pursuant to one or more Remarketing Agreements ("Remarketing
          Agreements") to be entered into by the Company and one or more
          nationally recognized investment banking firms chosen by the Company,
          as the remarketing agent (the "Remarketing Agent"), unless a Tax Event
          Redemption (as defined herein) has occurred, the Series M Notes
          pledged pursuant to the Pledge Agreement (as defined herein) will be
          remarketed (the "Initial Remarketing") on the third Business Day
          immediately preceding the Initial Reset Date (the "Initial Remarketing
          Date"). In the event that the Initial Remarketing results in a Failed
          Remarketing, provided a Tax Event Redemption has not occurred, the
          Series M Notes so pledged that are components of Corporate Units (as
          defined herein), the holders of which have not given notice on or
          prior to the fifth Business Day immediately preceding May 16, 2006
          (the "Purchase Contract Settlement Date") that they intend to settle
          the Purchase Contracts related to their Corporate Units with separate
          cash prior to the Purchase Contract Settlement Date and who have not
          settled their Purchase Contracts early, will be remarketed (the
          "Secondary Remarketing," and each of the Initial Remarketing and the
          Secondary Remarketing, a "Remarketing") on the third Business Day
          immediately preceding the Purchase Contract Settlement Date (the
          "Secondary Remarketing Date," and each of the Initial Remarketing Date
          and the Secondary Remarketing Date, a "Remarketing Date").

          Holders of Series M Notes that are not components of Corporate Units
          may elect to have their Series M Notes remarketed in either
          Remarketing, as applicable, in either case by providing notice of such
          election at least five Business Days prior to the applicable
          Remarketing Date but not earlier than the Interest Payment Date
          immediately preceding such Remarketing Date, and tendering their
          Series M Notes, along with a notice of such election, to the Custodial
          Agent, under, and in accordance with, the Pledge Agreement. Holders
          electing to have their Series M Notes remarketed will also have the
          right to withdraw such election on or prior to the fifth Business Day
          immediately preceding the applicable Remarketing Date by notice to the
          Custodial Agent in accordance with the provisions of the Pledge
          Agreement.

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          The Company will request, no later than seven nor more than 15
          calendar days prior to each Reset Announcement Date that DTC (as
          defined herein) notify its participants holding beneficial interests
          in such Series M Notes of such applicable Reset Announcement Date and
          of the procedures that must be followed by the holders of such
          beneficial interests in such Series M Notes electing to have their
          Series M Notes remarketed in the applicable Remarketing.

          On the third Business Day immediately preceding each Reset Date, the
          Reset Agent shall determine the Reset Rate for the Series M Notes by
          adding the applicable Reset Spread to the yield for the Applicable
          Benchmark Treasury on such date.

          The Remarketing Agent will use its reasonable efforts to remarket, on
          the Initial Remarketing Date, the Series M Notes tendered for the
          Initial Remarketing at a price of approximately 100.5% (but not less
          than 100%) of the Remarketing Treasury Portfolio Purchase Price, plus
          accrued and unpaid interest, if any, on the Series M Notes. After
          deducting as the remarketing fee an amount not exceeding 25 basis
          points (.25%) of the Remarketing Treasury Portfolio Purchase Price
          from any amount of the proceeds of the Initial Remarketing in excess
          of the Remarketing Treasury Portfolio Purchase Price, plus accrued and
          unpaid interest, if any, on the Series M Notes, the Remarketing Agent
          will remit the remaining portion of the proceeds of the Initial
          Remarketing to the Collateral Agent (with respect to Series M Notes
          that had been components of Corporate Units) or the Custodial Agent
          (with respect to other Series M Notes) in each case under, and subject
          to, the Pledge Agreement for the benefit of the holders. If the
          Remarketing Agent cannot remarket the Series M Notes, at a price of at
          least 100% of the Remarketing Treasury Portfolio Purchase Price, or if
          a condition precedent to the Initial Remarketing shall not have been
          fulfilled, then the Initial Remarketing shall be deemed to be a Failed
          Remarketing ("Failed Remarketing"). If the Initial Remarketing results
          in a Failed Remarketing, the interest rate on the Series M Notes will
          not be reset until May16, 2006.

          If the Initial Remarketing results in a Failed Remarketing, the
          Remarketing Agent will use its reasonable efforts to remarket, on the
          Secondary Remarketing Date, the Series M Notes tendered for the
          Secondary Remarketing at a price of approximately 100.5% (but not less
          than 100%) of the aggregate principal amount of such Series M Notes,
          plus accrued and unpaid interest, if any, on the Series M Notes. After
          deducting as the remarketing fee an amount not exceeding 25 basis
          points (.25%) of the aggregate principal amount of the Series M Notes
          so remarketed from any amount of the proceeds of the Secondary
          Remarketing in excess of the aggregate principal amount of such Series
          M Notes, plus such accrued and unpaid interest, if any, on the Series
          M Notes the Remarketing Agent will remit the remaining portion of the
          proceeds of the Secondary Remarketing to the Collateral Agent (with
          respect to Series M Notes that had been components of Corporate Units)
          or the Custodial Agent (with respect to other Series M Notes) in each
          case under, and subject to, the Pledge Agreement for the benefit of
          the holders, as provided in the Pledge Agreement. If the Remarketing
          Agent cannot remarket the Series M Notes tendered for a Remarketing at
          a price not less than 100% of the aggregate principal amount of such
          tendered Series M Notes, plus accrued and unpaid interest, if any, or
          if a condition precedent to the Secondary Remarketing shall not have

                                        4

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          been fulfilled, then such Secondary Remarketing shall be deemed to be
          a Failed Remarketing.

          "Applicable Principal Amount" means (i) on any date prior to the Reset
          Date, if any, the aggregate principal amount of Series M Notes that
          are components of Corporate Units on such date or (ii) on any date on
          or after the Reset Date, if any, the aggregate principal amount of
          Series M Notes Outstanding.

          "Remarketing Treasury Portfolio" means (a) interest or principal
          strips of U.S. Treasury Securities that mature on or prior to May 15,
          2006 in an aggregate amount equal to the principal amount of the
          Series M Notes included in Corporate Units; (b) with respect to the
          originally scheduled quarterly Interest Payment Date on the Series M
          Notes that would have occurred on May 16, 2006, interest or principal
          strips of U.S. Treasury Securities that mature on or prior to May 16,
          2006 in an aggregate amount equal to the aggregate interest payment
          that would be due on May 16, 2006 on the principal amount of the
          Series M Notes that would have been included in Corporate Units
          assuming no remarketing and assuming that the interest rate on the
          Series M Notes was not reset; and (c) if the Initial Reset Date occurs
          prior to February 16, 2006, with respect to the originally scheduled
          quarterly Interest Payment Date on the Series M Notes that would have
          occurred on February 16, 2006, interest or principal strips of U.S.
          Treasury Securities that mature on or prior to February 16, 2006 in an
          aggregate amount equal to the aggregate interest payment that would be
          due on February 16, 2006 on the principal amount of the Series M Notes
          that would have been included in the Corporate Units assuming no
          remarketing and assuming no reset of the interest rate on the Series M
          Notes and assuming that interest on the Series M Notes accrued from
          the Initial Reset Date to, but excluding, February 16, 2006.

          "Remarketing Treasury Portfolio Purchase Price" means the lowest
          aggregate price quoted by a Primary Treasury Dealer to the Quotation
          Agent on the third Business Day immediately preceding the Initial
          Reset Date for the purchase of the Remarketing Treasury Portfolio
          settlement on the Initial Reset Date.

          "Treasury Portfolio" means, as applicable, a Remarketing Treasury
          Portfolio or a Tax Event Treasury Portfolio.

          "Treasury Portfolio Purchase Price" means, as applicable, the
          Remarketing Treasury Portfolio Purchase Price or the Tax Event
          Treasury Portfolio Purchase Price.

5.        Each installment of interest on a Series M Note shall be payable to
          the Person in whose name such Series M Note is registered at the close
          of business on the Regular Record Date for such interest installment,
          which (a) as long as the Series M Notes remain in certificated form
          and are held by the Purchase Contract Agent or are held in book-entry
          form, will be one Business Day prior to the corresponding Interest
          Payment Date, or (b) if the Series M Notes are in certificated form,
          but are not held by the Purchase Contract Agent, or are not held in
          book-entry form, will be at least one Business Day but not more than
          60 Business Days prior to such corresponding Interest Payment Dates,
          as selected by the Company; provided that, unless the Purchase
          Contracts described in the Purchase

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          Contract Agreement (as defined herein) have been terminated, such
          Regular Record Date must be the same as the record date for the
          Corporate Units described in such Purchase Contract Agreement. The
          Security Registrar may, but shall not be required to, register the
          transfer of Series M Notes during the 10 days immediately preceding an
          Interest Payment Date. Any installment of interest on the Series M
          Notes not punctually paid or duly provided for shall forthwith cease
          to be payable to the Holders of such Series M Notes on such Regular
          Record Date, and may be paid to the Persons in whose name such Series
          M Notes are registered at the close of business on a Special Record
          Date to be fixed by the Trustee for the payment of such Defaulted
          Interest. Notice of such Defaulted Interest and Special Record Date
          shall be given to the Holders of such Series M Notes not less than 10
          days prior to such Special Record Date, or may be paid at any time in
          any other lawful manner not inconsistent with the requirements of any
          securities exchange on which such Series M Notes may be listed, and
          upon such notice as may be required by such exchange, all as more
          fully provided in the Indenture.

6.        The principal and each installment of interest on the Series M Notes
          shall be payable at, and registration of transfers and exchanges in
          respect of the Series M Notes may be effected at, the office or agency
          of the Company in The City of New York; provided that payment of
          interest may be made at the option of the Company by check mailed to
          the address of the Persons entitled thereto or by wire transfer to an
          account designated by the Person entitled thereto. Notices and demands
          to or upon the Company in respect of the Series M Notes may be served
          at the office or agency of the Company in The City of New York. The
          Corporate Trust Office of the Trustee will initially be the agency of
          the Company for such payment, registration and registration of
          transfers and exchanges and service of notices and demands and the
          Company hereby appoints the Trustee as its agent for all such
          purposes; provided, however, that the Company reserves the right to
          change, by one or more Officer's Certificates, any such office or
          agency and such agent. The Trustee will initially be the Security
          Registrar and the Paying Agent for the Series M Notes.

7.        If a Tax Event shall occur and be continuing, the Company may, at its
          option, redeem the Series M Notes in whole (but not in part) at any
          time ("Tax Event Redemption") at a Redemption Price equal to, for each
          Series M Note, the Redemption Amount (as herein defined) plus accrued
          and unpaid interest thereon, if any, to the date of redemption (the
          "Tax Event Redemption Date"). If such Tax Event Redemption occurs
          prior to the Initial Reset Date, or, if the Initial Remarketing
          results in a Failed Remarketing, prior to the Purchase Contract
          Settlement Date, the Redemption Price payable with respect to the
          Series M Notes pledged to the Collateral Agent under the Pledge
          Agreement dated as of June 1, 2002 by and among the Company, JPMorgan
          Chase Bank, as Collateral Agent, Custodial Agent and Securities
          Intermediary, and The Bank of New York, as Purchase Contract Agent
          (the "Pledge Agreement"), will be paid to the Collateral Agent on the
          Tax Event Redemption Date on or prior to 12:30 p.m., New York City
          time, by check or wire transfer in immediately available funds at such
          place and at such account as may be designated by the Collateral Agent
          in exchange for the Series M Notes pledged to the Collateral Agent.

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          "Tax Event" means the receipt by the Company of an opinion of
          nationally recognized independent tax counsel experienced in such
          matters (which may be Thelen Reid & Priest LLP) to the effect that
          there is more than an insubstantial risk that interest payable by the
          Company on the Series M Notes would not be deductible, in whole or in
          part, by the Company for United States federal income tax purposes as
          a result of any amendment to, change in, or announced proposed change
          in, the laws, or any regulations thereunder, of the United States or
          any political subdivision or taxing authority thereof or therein
          affecting taxation, any amendment to or change in an interpretation or
          application of any such laws or regulations by any legislative body,
          court, governmental agency or regulatory authority or any
          interpretation or pronouncement that provides for a position with
          respect to any such laws or regulations that differs from the
          generally accepted position on May 31, 2002, which amendment, change
          or proposed change is effective or which interpretation or
          pronouncement is announced on or after May 31, 2002.

          Notice of any redemption will be mailed at least 30 days but not more
          than 60 days before the Tax Event Redemption Date to each registered
          Holder of Series M Notes to be redeemed at its registered address as
          more fully provided in the Indenture. Unless the Company defaults in
          payment of the Redemption Price, on and after the Tax Event Redemption
          Date interest shall cease to accrue on such Series M Notes.

          "Primary Treasury Dealer" means a primary U.S. government securities
          dealer in New York City.

          "Quotation Agent" means (i) Merrill Lynch Government Securities, Inc.
          or its successor, provided, however, that, if the foregoing shall
          cease to be a Primary Treasury Dealer, the Company shall substitute
          therefor another Primary Treasury Dealer, and (ii) any other Primary
          Treasury Dealer selected by the Company.

          "Redemption Amount" means (a) in the case of a Tax Event Redemption
          occurring prior to the Initial Reset Date, or prior to May 16, 2006 if
          the remarketing of the Series M Notes on the third Business Day
          immediately preceding the Initial Reset Date resulted in a Failed
          Remarketing, for each Series M Note, the product of the principal
          amount of that Series M Note and a fraction whose numerator is the
          applicable Tax Event Treasury Portfolio Purchase Price and whose
          denominator is the aggregate principal amount of Series M Notes
          included in Corporate Units, and (b) in the case of a Tax Event
          Redemption occurring on or after the Initial Reset Date, or May 16,
          2006 if the remarketing of the Series M Notes on the third Business
          Day immediately preceding the Initial Reset Date resulted in a Failed
          Remarketing, for each Series M Note, the product of the principal
          amount of that Series M Note and a fraction whose numerator is the
          applicable Tax Event Treasury Portfolio Purchase Price and whose
          denominator is the sum of the aggregate principal amount of the Series
          M Notes Outstanding on the Tax Event Redemption Date.

          "Tax Event Treasury Portfolio" means (a) if the Tax Event Redemption
          occurs prior to the Initial Reset Date, or if the Series M Notes are
          not successfully remarketed on the third Business Day immediately
          preceding the Initial Reset Date, prior to May 16, 2006 (i) interest
          or principal strips of U.S. Treasury Securities that mature on or
          prior to

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          May 15, 2006 in an aggregate amount equal to the principal amount of
          Series M Notes included in the Corporate Units, and (ii) with respect
          to each Interest Payment Date that occurs after the Tax Event
          Redemption and on or before May 16, 2006, interest or principal strips
          of U.S. Treasury Securities which mature on or prior to that Interest
          Payment Date in an aggregate amount equal to the aggregate interest
          payment that would be due on the aggregate principal amount of the
          Series M Notes on that date if the interest rate of the Series M Notes
          was not reset on any applicable Reset Date; or (b) if the Tax Event
          Redemption occurs on or after the Initial Reset Date, or if the Series
          M Notes are not successfully remarketed on the third Business Day
          immediately preceding the Initial Reset Date, on or after May 16, 2006
          (i) interest or principal strips of U.S. Treasury Securities that
          mature on or prior to May 15, 2008 in an aggregate amount equal to the
          principal amount of Series M Notes Outstanding, and (ii) with respect
          to each Interest Payment Date that occurs after the Tax Event
          Redemption and on or before May 16, 2008, interest or principal strips
          of U.S. Treasury Securities which mature on or prior to such Interest
          Payment Date in an aggregate amount equal to the aggregate interest
          payment that would be due on the aggregate principal amount of the
          Series M Notes Outstanding on that date.

          "Tax Event Treasury Portfolio Purchase Price" means the lowest
          aggregate price quoted by the Primary Treasury Dealer to the Quotation
          Agent on the third Business Day immediately preceding the Tax Event
          Redemption Date for the purchase of applicable Tax Event Treasury
          Portfolio for settlement on the Tax Event Redemption Date.

8.        If the Secondary Remarketing results in a Failed Remarketing, Holders
          of Series M Notes will have the right to put their Series M Notes to
          the Company on June 30, 2006 for repayment as provided in the form of
          Series M Notes.

9.        Initially the Series M Notes will be issued in certificated form
          registered in the name of The Bank of New York, as Agent, under the
          Purchase Contract Agreement dated as of June 1, 2002 between the
          Company and The Bank of New York, as Agent (the "Purchase Contract
          Agreement") as components of certain securities of the Company
          referred to as Corporate Units (the "Corporate Units"), or in the name
          of Cede & Co. (as nominee for The Depository Trust Company ("DTC"),
          the initial securities depository for the Series M Notes that are not
          components of Corporate Units), and may bear such legends as either
          the Agent or DTC, respectively, may reasonably request.

10.       No service charge shall be made for the registration of transfer or
          exchange of the Series M Notes; provided, however, that the Company
          may require payment of a sum sufficient to cover any tax or other
          governmental charge that may be imposed in connection with the
          exchange or transfer.

11.       If the Company shall make any deposit of money and/or Eligible
          Obligations with respect to any Series M Notes, or any portion of the
          principal amount thereof, as contemplated by Section 701 of the
          Indenture, the Company shall not deliver an Officer's Certificate
          described in clause (z) in the first paragraph of said Section 701
          unless the Company shall also deliver to the Trustee, together with
          such Officer's Certificate, either:

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<PAGE>

                    (A) an instrument wherein the Company, notwithstanding the
          satisfaction and discharge of its indebtedness in respect of the
          Series M Notes, shall assume the obligation (which shall be absolute
          and unconditional) to irrevocably deposit with the Trustee or Paying
          Agent such additional sums of money, if any, or additional Eligible
          Obligations (meeting the requirements of Section 701), if any, or any
          combination thereof, at such time or times, as shall be necessary,
          together with the money and/or Eligible Obligations theretofore so
          deposited, to pay when due the principal of and premium, if any, and
          interest due and to become due on such Series M Notes or portions
          thereof, all in accordance with and subject to the provisions of said
          Section 701; provided, however, that such instrument may state that
          the obligation of the Company to make additional deposits as aforesaid
          shall be subject to the delivery to the Company by the Trustee of a
          notice asserting the deficiency accompanied by an opinion of an
          independent public accountant of nationally recognized standing,
          selected by the Trustee, showing the calculation thereof; or

                    (B) an Opinion of Counsel to the effect that, as a result of
          a change in law occurring after the date of this certificate, the
          Holders of such Series M Notes, or portions of the principal amount
          thereof, will not recognize income, gain or loss for United States
          federal income tax purposes as a result of the satisfaction and
          discharge of the Company's indebtedness in respect thereof and will be
          subject to United States federal income tax on the same amounts, at
          the same times and in the same manner as if such satisfaction and
          discharge had not been effected.

12.       The Series M Notes shall have such other terms and provisions as are
          provided in the forms thereof set forth in Exhibit A hereto and shall
          be issued in substantially such forms.

13.       The undersigned has read all of the covenants and conditions contained
          in the Indenture relating to the issuance of the Series M Notes and
          the definitions in the Indenture relating thereto and in respect of
          which this certificate is made.

14.       The statements contained in this certificate are based upon the
          familiarity of the undersigned with the Indenture, the documents
          accompanying this certificate, and upon discussions by the undersigned
          with officers and employees of the Company familiar with the matters
          set forth herein.

15.       In the opinion of the undersigned, he has made such examination or
          investigation as is necessary to enable him to express an informed
          opinion whether or not such covenants and conditions have been
          complied with.

16.       In the opinion of the undersigned, such conditions and covenants and
          conditions precedent, if any (including any covenants compliance with
          which constitutes a condition precedent) to the authentication and
          delivery of $440,000,000 aggregate principal amount of Series M Notes,
          as requested in the accompanying Company Order 1-D-1, have been
          complied with.

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          IN WITNESS WHEREOF, I have executed this Officer's Certificate this
5th day of June, 2002.

                                By /s/ Kirk R. Oliver
                                   -----------------------
                                   Name: Kirk R. Oliver
                                   Title: Treasurer

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                                                                       EXHIBIT A

                               [depository legend]

          [Unless this Certificate is presented by an authorized representative
of The Depository Trust Company, a New York corporation ("DTC"), to the Company
or its agent for registration of transfer, exchange, or payment, and any
certificate issued is registered in the name of Cede & Co. or in such other name
as is requested by an authorized representative of DTC (and any payment is made
to Cede & Co. or to such other entity as is requested by an authorized
representative of DTC), ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner
hereof, Cede & Co., has an interest herein.]

                         [FORM OF FACE OF SERIES M NOTE]

                                    TXU CORP.

                      SERIES M SENIOR NOTE DUE MAY 16, 2008

               TXU CORP., a corporation duly organized and existing under the
laws of the State of Texas (herein referred to as the "Company", which term
includes any successor Person under the Indenture), for value received, hereby
promises to pay to

or registered assigns, the principal sum of __________ Dollars on May 16, 2008,
and to pay interest on said principal sum quarterly on (i) February 16, May 16,
August 16 and November 16 of each year commencing August 16, 2002, and (ii) the
Initial Reset Date if the remarketing of the Securities of these series on the
third Business Day immediately preceding the Initial Reset Date is successful
and the Initial Reset Date is not November 16, 2005 or February 16, 2006; and
(b) semi-annually in arrears on each May 16 and November 16 after the Initial
Reset Date, or May 16, 2006, if the interest rate on the Securities of this
series is not reset on the Initial Reset Date (each, an "Interest Payment
Date"), initially at the rate of 5.8% per annum until the Reset Date, if any,
and at the Reset Rate on and after the Reset Date, if any, until the principal
hereof is paid or made available for payment. Interest on the Securities of this
series will accrue from June 5, 2002, to the first Interest Payment Date, and
thereafter will accrue from the last Interest Payment Date to which interest has
been paid or duly provided for. In the event that any Interest Payment Date is
not a Business Day, then payment of interest payable on such date will be made
on the next succeeding day which is a Business Day (and without any interest or
other payment in respect of such delay), except that, if such Business Day is in
the next succeeding calendar year, then such payment shall be made on the
immediately preceding Business Day, in each case, with the same force and effect
as if made on the Interest Payment Date. The interest so payable, and punctually
paid or duly provided for, on any Interest Payment Date will, as provided in
such Indenture, be paid to the Person in whose name this Security (or one or
more Predecessor Securities) is registered at the close of business on the
Regular Record Date for such interest, which (a) as long as the Securities of
this series remain in certificated form and are held by the Purchase Contract
Agent or are held in book-entry form, will be one Business Day prior to the
corresponding Interest Payment Date, or (b) if the Securities of this series are
in certificated

                                       11

<PAGE>

form, but are not held by the Purchase Contract Agent, or are not held in
book-entry form, will be at least one Business Day but not more than 60 Business
Days prior to such corresponding Interest Payment Dates, as selected by the
Company for the corresponding Interest Payment Date. Any such interest not so
punctually paid or duly provided for will forthwith cease to be payable to the
Holder on such Regular Record Date and may either be paid to the Person in whose
name this Security (or one or more Predecessor Securities) is registered at the
close of business on a Special Record Date for the payment of such Defaulted
Interest to be fixed by the Trustee, notice whereof shall be given to Holders of
Securities of this series not less than 10 days prior to such Special Record
Date, or may be paid at any time in any other lawful manner not inconsistent
with the requirements of any securities exchange on which the Securities of this
series may be listed, and upon such notice as may be required by such exchange,
all as more fully provided in the Indenture referred to on the reverse hereof.

               Payment of the principal of (and premium, if any) and interest on
this Security will be made at the office or agency of the Company maintained for
that purpose in The City of New York, the State of New York in such coin or
currency of the United States of America as at the time of payment is legal
tender for payment of public and private debts; provided, however, that, at the
option of the Company, interest on this Security may be paid by check mailed to
the address of the Person entitled thereto, as such address shall appear on the
Security Register or by wire transfer to an account designated by the person
entitled thereto.

               Reference is hereby made to the further provisions of this
Security set forth on the reverse hereof, which further provisions shall for all
purposes have the same effect as if set forth at this place.

               Unless the certificate of authentication hereon has been executed
by the Trustee referred to on the reverse hereof by manual signature, this
Security shall not be entitled to any benefit under the Indenture or be valid or
obligatory for any purpose.

                                       12

<PAGE>

               IN WITNESS WHEREOF, the Company has caused this instrument to be
duly executed.

                                     TXU CORP.

                                     By:
                                         ---------------------------------------

                          CERTIFICATE OF AUTHENTICATION

Dated:

               This is one of the Securities of the series designated therein
referred to in the within-mentioned Indenture.

                                     THE BANK OF NEW YORK, as Trustee

                                     By:
                                         ---------------------------------------
                                                 Authorized Signatory

                                       13

<PAGE>

                       [FORM OF REVERSE OF SERIES M NOTE]

               This Security is one of a duly authorized issue of securities of
the Company (herein called the "Securities"), issued and to be issued in one or
more series under an Indenture (For Unsecured Debt Securities Series M), dated
as of June 1, 2002 (herein, together with any amendments thereto, called the
"Indenture", which term shall have the meaning assigned to it in such
instrument), between the Company and The Bank of New York, as Trustee (herein
called the "Trustee," which term includes any successor trustee under the
Indenture), and reference is hereby made to the Indenture, including the Board
Resolutions and Officer's Certificate filed with the Trustee on June 1, 2002
creating the series designated on the face hereof (herein called, the "Officer's
Certificate"), for a statement of the respective rights, limitations of rights,
duties and immunities thereunder of the Company, the Trustee and the Holders of
the Securities and of the terms upon which the Securities are, and are to be,
authenticated and delivered.

               If a Tax Event shall occur and be continuing, the Company may, at
its option, redeem the Securities of this series in whole (but not in part) at
any time at a Redemption Price equal to the Redemption Amount plus accrued and
unpaid interest thereon to the Tax Event Redemption Date.

               The Holder of this Security may, on or prior to the fifth
Business Day immediately preceding the Initial Reset Date or May 16, 2006 tender
this Security to JPMorgan Chase Bank, as Custodial Agent, for remarketing in
accordance with the Pledge Agreement dated as of June 1, 2002 among the Company,
The Bank of New York and JPMorgan Chase Bank, as Collateral Agent, Custodial
Agent and Securities Intermediary.

               If the Secondary Remarketing has resulted in a Failed
Remarketing, each Holder of Securities of this series who holds such Securities
on the day immediately following the Purchase Contract Settlement Date shall
have the right to put such Holder's Securities of this series to the Company on
June 30, 2006 (the "Put Option Exercise Date"), upon at least three Business
Days' prior notice, at a price equal to the principal amount of such Securities,
plus accrued and unpaid interest, if any thereon (the "Repayment Price").

               In order for the Securities to be so repurchased, the Company
must receive, on or prior to 5:00 p.m. New York City Time on the third Business
Day immediately preceding the Put Option Exercise Date, at the then principal
executive offices of the Company, the Securities of this series to be
repurchased with the form entitled "Option to Elect Repayment" on the reverse of
or otherwise accompanying such Securities duly completed. Any such notice
received by the Company shall be irrevocable. All questions as to the validity,
eligibility (including time of receipt) and acceptance of the Securities of this
series for repayment shall be determined by the Company, whose determination
shall be final and binding. The payment of the Repayment Price in respect of
such Securities of this series shall be made, either through the Trustee or the
Company acting as Paying Agent, no later than 12:00 noon, New York City time, on
the Put Option Exercise Date.

               The Indenture contains provisions for defeasance at any time of
the entire indebtedness of this Security upon compliance with certain conditions
set forth in the Indenture.

                                       14

<PAGE>

               If an Event of Default with respect to Securities of this series
shall occur and be continuing, the principal of the Securities of this series
may be declared due and payable in the manner and with the effect provided in
the Indenture.

               The Indenture permits, with certain exceptions as therein
provided, the amendment thereof and the modification of the rights and
obligations of the Company and the rights of the Holders of the Securities of
each series to be affected under the Indenture at any time by the Company and
the Trustee with the consent of the Holders of a majority in principal amount of
the Securities at the time Outstanding of all series to be affected. The
Indenture contains provisions permitting the Holders of a majority in aggregate
principal amount of the Securities of all series then Outstanding to waive
compliance by the Company with certain provisions of the Indenture. The
Indenture also contains provisions permitting the Holders of specified
percentages in principal amount of the Securities of each series at the time
Outstanding, on behalf of the Holders of all Securities of such series, to waive
compliance by the Company with certain provisions of the Indenture and certain
past defaults under the Indenture and their consequences. Any such consent or
waiver by the Holder of this Security shall be conclusive and binding upon such
Holder and upon all future Holders of this Security and of any Security issued
upon the registration of transfer hereof or in exchange herefor or in lieu
hereof, whether or not notation of such consent or waiver is made upon this
Security.

               As provided in and subject to the provisions of the Indenture,
the Holder of this Security shall not have the right to institute any proceeding
with respect to the Indenture or for the appointment of a receiver or trustee or
for any other remedy thereunder, unless such Holder shall have previously given
the Trustee written notice of a continuing Event of Default with respect to the
Securities of this series, the Holders of a majority in aggregate principal
amount of the Securities of all series at the time Outstanding in respect of
which an Event of Default shall have occurred and be continuing shall have made
written request to the Trustee to institute proceedings in respect of such Event
of Default as Trustee and offered the Trustee reasonable indemnity, and the
Trustee shall not have received from the Holders of a majority in aggregate
principal amount of Securities of all series at the time Outstanding in respect
of which an Event of Default shall have occurred and be continuing a direction
inconsistent with such request, and shall have failed to institute any such
proceeding, for 60 days after receipt of such notice, request and offer of
indemnity. The foregoing shall not apply to any suit instituted by the Holder of
this Security for the enforcement of any payment of principal hereof or any
premium or interest hereon on or after the respective due dates expressed
herein.

               No reference herein to the Indenture and no provision of this
Security or of the Indenture shall alter or impair the obligation of the
Company, which is absolute and unconditional, to pay the principal of and any
premium and interest on this Security at the times, place and rate, and in the
coin or currency, herein prescribed.

               The Securities of this series are issuable only in registered
form without coupons in denominations of $50. As provided in the Indenture and
subject to certain limitations therein set forth, Securities of this series are
exchangeable for a like aggregate principal amount of Securities of this series
and of like tenor and of authorized denominations, as requested by the Holder
surrendering the same.

                                       15

<PAGE>

               No service charge shall be made for any such registration of
transfer or exchange, but the Company may require payment of a sum sufficient to
cover any tax or other governmental charge payable in connection therewith.

               The Company, the Trustee and any agent of the Company or the
Trustee may treat the Person in whose name this Security is registered as the
absolute owner hereof for all purposes, whether or not this Security be overdue,
and neither the Company, the Trustee nor any such agent shall be affected by
notice to the contrary.

               All terms used in this Security which are defined in the
Indenture and the Officer's Certificate shall have the meanings assigned to them
in the Indenture and in the Officer's Certificate.

                                       16

<PAGE>

                            OPTION TO ELECT REPAYMENT

               The undersigned hereby irrevocably requests and instructs the
Company to repay $______ principal amount of the within Security, pursuant to
its terms, on the "Put Option Exercise Date," together with any interest thereon
accrued but unpaid to the date of repayment, to the undersigned at:

________________________________________________________________________________
           (Please print or type name and address of the undersigned)

and to issue to the undersigned, pursuant to the terms of the Security, a new
Security or Securities representing the remaining aggregate principal amount of
this Security.

               For this Option to Elect Repayment to be effective, this Security
with the Option to Elect Repayment duly completed must be received by the
Company at its principal executive office, Attn: Secretary, no later than 5:00
p.m. on the third Business Day prior to June 30, 2006.

Dated:

                                      Signature:
                                                -------------------------------

                            Signature Guarantee:
                                                -------------------------------

Note: The signature to this Option to Elect Repayment must correspond with the
name as written upon the face of the within Security without alternation or
enlargement or any change whatsoever.

                               SIGNATURE GUARANTEE

          Signatures must be guaranteed by an "eligible guarantor institution"
meeting the requirements of the Registrar, which requirements include membership
or participation in the Security Transfer Agent Medallion Program ("STAMP") or
such other "signature guarantee program" as may be determined by the Registrar
in addition to, or in substitution for, STAMP, all in accordance with the
Securities Exchange Act of 1934, as amended.

                                       17

<PAGE>

                                   ASSIGNMENT

FOR VALUE RECEIVED, the undersigned assigns and transfers this Series M Senior
Note due May 16, 2008 to:

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________
        (Insert assignee's social security or tax identification number)

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________
                    (Insert address and zip code of assignee)

and irrevocably appoints

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

agent to transfer this Security on the Security Register. The agent may
substitute another to act for him or her.

Date:___________________

                                      Signature:
                                                --------------------------------

                            Signature Guarantee:
                                                --------------------------------

     (Sign exactly as your name appears on the other side of this Security)

                               SIGNATURE GUARANTEE

          Signatures must be guaranteed by an "eligible guarantor institution"
meeting the requirements of the Registrar, which requirements include membership
or participation in the Security Transfer Agent Medallion Program ("STAMP") or
such other "signature guarantee program" as may be determined by the Registrar
in addition to, or in substitution for, STAMP, all in accordance with the
Securities Exchange Act of 1934, as amended.

                                       18