FIFTY-SECOND SUPPLEMENTAL
                                    INDENTURE

                                       TO

                        INDENTURE DATED SEPTEMBER 1, 1939

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


                                PSI ENERGY, INC.
          (FORMERLY NAMED "PUBLIC SERVICE COMPANY OF INDIANA, INC." AND
        SUCCESSOR BY CONSOLIDATION TO PUBLIC SERVICE COMPANY OF INDIANA)

                                       TO

                              LASALLE NATIONAL BANK
                                   AS TRUSTEE
                (SUCCESSOR TO THE FIRST NATIONAL BANK OF CHICAGO)

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


                           DATED AS OF APRIL 30, 1999

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



        CREATING FIRST MORTGAGE BONDS, SERIES BBB, 8%, DUE JULY 15, 2009,
       FIRST MORTGAGE BONDS, SERIES CCC, 8.85%, DUE JANUARY 15, 2022, AND
         FIRST MORTGAGE BONDS, SERIES DDD, 8.31%, DUE SEPTEMBER 1, 2032

                                       AND

               OTHERWISE SUPPLEMENTING AND AMENDING THE INDENTURE















                                TABLE OF CONTENTS

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


                                                                            Page

PARTIES:
     Company (PSI Energy, Inc. formerly named Public Service Company
         of Indiana, Inc., successor by consolidation to Initial Mortgagor
         (Public Service Company of Indiana)), and Trustee                    1


RECITALS:
     Indenture of the Initial  Mortgagor,  dated  September  1, 1939,  and First
         Supplemental Indenture thereto of the Initial Mortgagor, dated
         as of March 1, 1941                                                  1
     Consolidation of Initial Mortgagor (and four other companies) into the
         Company                                                              1
     Execution by Company of Second Supplemental Indenture to the original
         Indenture                                                            1
     Company substituted for Initial Mortgagor under Indenture                1
     Execution by Company of Third through the Fifty-First Supplemental
         Indentures to the original Indenture                                 2
     LaSalle National Bank, successor to original Trustee                     2
     Change of name of Company from Public Service Company of Indiana,
         Inc. to PSI Energy, Inc.                                             3
     Amount of bonds presently outstanding under the Indenture                3
     Fifty-Second Supplemental Indenture and Bonds of Series BBB, CCC,
              and DDD authorized                                              3
     Conditions precedent performed                                           3

EXECUTING CLAUSE                                                              4




                                      - i -







                                                                           Page
                                   ARTICLE I.

            FIRST MORTGAGE BONDS, SERIES BBB, 8%, DUE JULY 15, 2009,
       FIRST MORTGAGE BONDS, SERIES CCC, 8.85%, DUE JANUARY 15, 2022, AND
         FIRST MORTGAGE BONDS, SERIES DDD, 8.31%, DUE SEPTEMBER 1, 2032.

Section 1..Creation and designation of Bonds of Series BBB, CCC and DDD      4
Section 2..Bonds of Series BBB, CCC, and DDD to be in registered form only   4
              Form of face of Bonds of Series BBB                            9
              Form of reverse of Bonds of Series BBB and Trustee's 
                certificate                                                 11
              Form of face of Bonds of Series CCC                           15
              Form of reverse of Bonds of Series CCC and Trustee's 
                certificate                                                 17
              Form of face of Bonds of Series DDD                           21
              Form of reverse of Bonds of Series DDD and Trustee's 
                certificate                                                 23
Section 3..Date of Bonds of Series BBB, CCC, and DDD                        27
Section 4..Maturity dates and interest rates of Bonds of Series BBB, CCC,
                  and DDD                                                   27
Section 5..Place and manner of payment of Bonds of Series BBB, CCC,
                  and DDD                                                   27
Section 6..Denominations and numbering of definitive Bonds of Series BBB,
                  CCC and DDD                                               27
           Temporary Bonds of Series BBB, CCC, and DDD and exchange
                  thereof for definitive bonds                              27


                                   ARTICLE II.

                 ISSUANCE OF BONDS OF SERIES BBB, CCC, AND DDD.

Section 1..Aggregate principal amount of Bonds of Series BBB, Bonds
                  of Series CCC, and Bonds of Series DDD issuable at once   28
Section 2..Issuance of additional Bonds of Series BBB, CCC, and DDD         28


                                  ARTICLE III.

                              INDENTURE AMENDMENTS.

Section 1..Amendments to Article I of the original Indenture                28
Section 2..Amendments to Article VII of the original Indenture              29
Section 3..Amendments to Article IX of the original Indenture               31
Section 4..Amendments to Section 22 of Article V of the original Indenture  31
Section 5..Company's right to further amend the original Indenture          31



                                     - ii -






                                                                           Page

                                   ARTICLE IV.

                             CONCERNING THE TRUSTEE.

Acceptance of trust by Trustee                                              32
Trustee not responsible for validity or sufficiency of Fifty-Second
     Supplemental Indenture, etc.                                           32
Terms and conditions of Article XVII of the original Indenture to be applied
     to the Fifty-Second Supplemental Indenture                             32


                                   ARTICLE V.

                            MISCELLANEOUS PROVISIONS.

Section 1..References in any article or section of the original Indenture refer
                  to such article or section as amended by all Fifty-Two
                  Supplemental Indentures thereto                           33
Section 2..Operation and construction of amendments to the original 
             Indenture                                                      33
Section 3..All covenants, etc., for sole benefit of parties to the Fifty-Second
                  Supplemental Indenture and holders of bonds               33
Section 4..Table of contents and headings of articles not part of Fifty-Second
                  Supplemental Indenture                                    33
Section 5..Execution of Fifty-Second Supplemental Indenture in 
             counterparts                                                   33
Section 6..Payments Due on Legal Holidays                                   33


ATTESTATION CLAUSE                                                          34
SIGNATURES                                                                  34
ACKNOWLEDGMENT BY COMPANY                                                   35
ACKNOWLEDGMENT BY TRUSTEE                                                   36







                                     - iii -






         FIFTY-SECOND  SUPPLEMENTAL  INDENTURE  dated as of the thirtieth day of
April, 1999, made and entered into by and between PSI ENERGY, INC.  (hereinafter
commonly  referred to as the  "Company"),  a corporation  organized and existing
under the laws of the State of Indiana, formerly named Public Service Company of
Indiana,  Inc., and the successor by  consolidation to Public Service Company of
Indiana, an Indiana  corporation,  party of the first part, and LASALLE NATIONAL
BANK, a national  banking  association  organized and existing under the laws of
the United  States and  having  its office or place of  business  in the City of
Chicago,  State of Illinois and the successor trustee to The First National Bank
of Chicago  (hereinafter  commonly  referred to as the "Trustee"),  party of the
second part,

         WITNESSETH:

         WHEREAS,  Public  Service  Company  of  Indiana  (hereinafter  commonly
referred to as the "Initial Mortgagor"), prior to its consolidation with certain
other corporations to form the Company,  executed and delivered to the Trustee a
certain indenture of mortgage or deed of trust (hereinafter called the "original
Indenture" when referred to as existing prior to any amendment thereto,  and the
"Indenture"  when referred to as heretofore,  now or hereafter  amended),  dated
September 1, 1939, and a First Supplemental Indenture thereto, dated as of March
1, 1941,  to secure  the bonds of the  Initial  Mortgagor,  its  successors  and
assigns, issued from time to time under the Indenture in series for the purposes
of and subject to the limitations specified in the Indenture; and

         WHEREAS,   the  Company  on  September  6,  1941,  became,   through  a
consolidation, the successor of the Initial Mortgagor (and four other companies)
and succeeded to all the rights and became liable for all the obligations of the
Initial Mortgagor (and such other companies); and

         WHEREAS, after said consolidation, the Company executed and delivered a
Second  Supplemental  Indenture,  dated as of November 1, 1941,  to the original
Indenture for the purposes, among others, of (i) the making by the Company of an
agreement of assumption and adoption by it of the Indenture, (ii) the assumption
by the Company of the bonds (and interest and premium,  if any,  thereon) issued
or to be issued under the Indenture,  and of all terms, covenants and conditions
binding  upon it under the  Indenture,  and the  agreeing by the Company to pay,
perform and fulfill the same,  and (iii) the  conveying  to the Trustee upon the
trusts  declared  in the  Indenture,  but subject to any  outstanding  liens and
encumbrances,  all the  property  which the Company then owned or which it might
thereafter  acquire,  except property of a character  similar to the property of
the Initial Mortgagor which is excluded from the lien of the Indenture; and

         WHEREAS, all conditions have been met and all acts and things necessary
have been  done and  performed  to make the  Indenture  the  valid  and  binding
agreement of the Company and to substitute the Company for the Initial Mortgagor
under the Indenture, and to vest the Company with each and every right and power
of the  Initial  Mortgagor,  including  the  right  and  power  to  issue  bonds
thereunder; and

         WHEREAS,  the Company has  subsequently  executed  and  delivered,  for
purposes authorized under the Indenture, a Third Supplemental Indenture dated as
of March 1, 1942,  a Fourth  Supplemental  Indenture  dated as of May 1, 1943, a
Fifth  Supplemental  Indenture dated as of August 1, 1944, a Sixth  Supplemental
Indenture dated as of September 1, 1945, a Seventh Supplemental  Indenture dated
as of November 1, 1947, an Eighth Supplemental  Indenture dated as of January 1,
1949,  a  Ninth  Supplemental  Indenture  dated  as of  May  1,  1950,  a  Tenth
Supplemental  Indenture  dated  as of July 1,  1952,  an  Eleventh  Supplemental
Indenture dated as of January 1, 1954, a Twelfth Supplemental Indenture dated as
of October 1, 1957, a Thirteenth  Supplemental Indenture dated as of February 1,
1959, a Fourteenth Supplemental Indenture dated as of July 15, 1960, a Fifteenth
Supplemental  Indenture  dated as of June 15,  1964,  a  Sixteenth  Supplemental
Indenture  dated as of January 1, 1969,  a  Seventeenth  Supplemental  Indenture
dated as of March 1, 1970,  an  Eighteenth  Supplemental  Indenture  dated as of
January 1, 1971,  a  Nineteenth  Supplemental  Indenture  dated as of January 1,
1972,  a  Twentieth  Supplemental  Indenture  dated as of  February  1, 1974,  a
Twenty-First  Supplemental Indenture dated as of August 1, 1974, a Twenty-Second
Supplemental  Indenture dated as of August 1, 1975, a Twenty-Third  Supplemental
Indenture  dated as of January 1, 1977, a Twenty-Fourth  Supplemental  Indenture
dated as of October 1, 1977, a Twenty-Fifth  Supplemental  Indenture dated as of
September 1, 1978, a Twenty-Sixth  Supplemental  Indenture dated as of September
1, 1978, a  Twenty-Seventh  Supplemental  Indenture dated as of March 1, 1979, a
Twenty-Eighth  Supplemental  Indenture  dated as of May 1, 1979, a  Twenty-Ninth
Supplemental  Indenture  dated as of March 1,  1980,  a  Thirtieth  Supplemental
Indenture  dated as of August 1, 1980,  a  Thirty-First  Supplemental  Indenture
dated as of February 1, 1981, a Thirty-Second Supplemental Indenture dated as of
August 1, 1981, a Thirty-Third  Supplemental  Indenture  dated as of December 1,
1981, a  Thirty-Fourth  Supplemental  Indenture  dated as of December 1, 1982, a
Thirty-Fifth  Supplemental  Indenture dated as of March 30, 1984, a Thirty-Sixth
Supplemental   Indenture  dated  as  of  November  15,  1984,  a  Thirty-Seventh
Supplemental Indenture dated as of August 15, 1985, a Thirty-Eighth Supplemental
Indenture  dated as of October 1, 1986, a  Thirty-Ninth  Supplemental  Indenture
dated as of March 15, 1987, a Fortieth  Supplemental  Indenture dated as of June
1, 1987,  a  Forty-First  Supplemental  Indenture  dated as of June 15,  1988, a
Forty-Second  Supplemental  Indenture  dated as of August 1, 1988, a Forty-Third
Supplemental   Indenture   dated  as  of  September  15,  1989,  a  Forty-Fourth
Supplemental  Indenture  dated as of March 15, 1990, a Forty-Fifth  Supplemental
Indenture dated as of March 15, 1990, a Forty-Sixth Supplemental Indenture dated
as of June 1, 1990, a Forty-Seventh  Supplemental Indenture dated as of July 15,
1991,  a  Forty-Eighth  Supplemental  Indenture  dated  as of July 15,  1992,  a
Forty-Ninth  Supplemental  Indenture  dated as of February  15, 1993, a Fiftieth
Supplemental  Indenture  dated  as of  February  15,  1993,  and  a  Fifty-First
Supplemental  Indenture  dated as of February 1, 1994,  each  supplementing  and
amending the Indenture; and

         WHEREAS,  the  Thirty-Fifth   Supplemental   Indenture  authorized  and
appointed  LaSalle National Bank, a national banking  association duly organized
and existing  under the law of the United  States of America with its  principal
office in Chicago,  Illinois, as Successor Trustee to The First National Bank of
Chicago,  which  appointment  was  accepted,  and all  trust  powers  under  the
Indenture  were thereby  transferred  from The First National Bank of Chicago to
LaSalle National Bank; and

     WHEREAS,  the Forty-Sixth  Supplemental  Indenture amended the Indenture to
reflect a change in the name of the  Company  from  Public  Service  Company  of
Indiana, Inc. to PSI Energy, Inc. effective as of April 20, 1990; and

         WHEREAS, as of April 30, 1999, the only bonds that have been heretofore
issued under the Indenture which are now  outstanding are $10,000,000  aggregate
principal  amount of "Public  Service  Company of Indiana,  Inc.  First Mortgage
Bonds,  Series  TT, 7 3/8%,  Due  March  15,  2012"  and  $14,250,000  aggregate
principal  amount of "Public  Service  Company of Indiana,  Inc.  First Mortgage
Bonds,  Series  UU, 7 1/2%,  Due March  15,  2015"  and  $300,000,000  aggregate
principal amount of "PSI Energy,  Inc. First Mortgage Bonds, Series VV, Due July
15, 2026" and $545,000,000 aggregate principal amount of "PSI Energy, Inc. First
Mortgage  Bonds,  Series  WW, Due August  15,  2027" and  $29,945,000  aggregate
principal  amount of "PSI Energy,  Inc. First Mortgage Bonds,  Series YY, 5.60%,
Due  February  15,  2023" and  $50,000,000  aggregate  principal  amount of "PSI
Energy, Inc. First Mortgage Bonds, Series ZZ, 5 3/4%, Due February 15, 2028" and
$50,000,000  aggregate  principal  amount of "PSI Energy,  Inc.  First  Mortgage
Bonds, Series AAA, 7 1/8%, Due February 1, 2024"; and

         WHEREAS,  in  accordance  with the  provisions  of Section 1 of Article
XVIII of the Indenture,  the Board of Directors has authorized the execution and
delivery by the Company of a Fifty-Second Supplemental Indenture,  substantially
in the form of this  Fifty-Second  Supplemental  Indenture,  for the  purpose of
creating a forty-seventh, a forty-eighth and a forty-ninth series of bonds to be
issued under the  Indenture,  to be known as,  respectively,  "PSI Energy,  Inc.
First  Mortgage  Bonds,  Series  BBB,  8%, Due July 15,  2009" (such bonds being
hereinafter  referred to as "Bonds of Series  BBB"),  "PSI  Energy,  Inc.  First
Mortgage  Bonds,  Series CCC,  8.85%,  Due  January 15,  2022" (such bonds being
hereinafter  referred to as "Bonds of Series CCC") and "PSI Energy,  Inc.  First
Mortgage  Bonds,  Series DDD,  8.31%,  Due  September 1, 2032" (such bonds being
hereinafter  referred to as "Bonds of Series DDD") (the Bonds of Series BBB, the
Bonds of Series CCC, and the Bonds of Series DDD, when referred to  collectively
in this Fift Second Supplemental Indenture,  shall be hereinafter referred to as
"Bonds of Series BBB, CCC, and DDD"),  and prescribing the form and substance of
the  Bonds  of  Series  BBB,  CCC,  and  DDD  and  the  terms,   provisions  and
characteristics  thereof,  and for the  purpose of adding to the  covenants  and
agreements of the Company for the protection of the bondholders and of the trust
estate and of making such changes in the  Indenture  as are deemed  necessary or
desirable and as are permitted by the Indenture; and

         WHEREAS,  all  conditions  and  requirements  necessary  to  make  this
Fifty-Second  Supplemental  Indenture a valid, binding and legal instrument have
been done,  performed and  fulfilled and the execution and delivery  hereof have
been in all respects duly authorized:

         NOW, THEREFORE, in consideration of the premises, and of the acceptance
and  purchase  of the Bonds of  Series  BBB,  CCC,  and DDD by the  holders  and
registered owners thereof, and of the sum of One Dollar ($1.00) duly paid by the
Trustee to the  Company,  the  receipt  whereof is hereby  acknowledged,  and in
accordance  with and subject to the terms and provisions of the  Indenture,  the
Company and the Trustee, respectively, have entered into, executed and delivered
this Fifty-Second  Supplemental  Indenture for the uses and purposes hereinafter
expressed, that is to say:
                                                       
                                   ARTICLE I.
                                                   
            FIRST MORTGAGE BONDS, SERIES BBB, 8%, DUE JULY 15, 2009,
        FIRST MORTGAGE BONDS, SERIES CCC, 8.85%, DUE JANUARY 1, 2022, AND
         FIRST MORTGAGE BONDS, SERIES DDD, 8.31%, DUE SEPTEMBER 1, 2032

         Section 1. There are hereby created a forty-seventh, a forty-eighth and
a forty-ninth  series of bonds to be issued under and secured by the  Indenture,
to be designated as "PSI Energy,  Inc. First Mortgage Bonds, Series BBB, 8%, Due
July 15, 2009", "PSI Energy,  Inc. First Mortgage Bonds,  Series CCC, 8.85%, Due
January 15, 2022" and "PSI Energy, Inc. First Mortgage Bonds, Series DDD, 8.31%,
Due September 1, 2032",  respectively,  being the Bonds of Series BBB, the Bonds
of Series CCC, and the Bonds of Series DDD, or collectively, the Bonds of Series
BBB, CCC, and DDD, hereinbefore referred to.

         Section 2. The following  provisions shall apply to the Bonds of Series
BBB, CCC, and DDD.

                  (a) The Bonds of Series BBB,  CCC,  and DDD shall be issued in
         fully registered form only.  However,  except as provided  elsewhere in
         this Section,  the registered  owner of all of the Bonds of Series BBB,
         CCC, and DDD initially shall be The Depository Trust Company ("DTC") or
         its nominee, and such Bonds of Series BBB, CCC, and DDD initially shall
         be  registered  in the  name  of DTC or  its  nominee.  Payment  of the
         principal  of or  interest  on  Bonds  of  Series  BBB,  CCC,  and  DDD
         registered  in the  name  of DTC or its  nominee  shall  be made in the
         manner   and  at  the   address(es)   specified   in  the   Letter   of
         Representations, dated April 30, 1999, from the Company and the Trustee
         to DTC.  DTC  (and any  successor  securities  depository)  and its (or
         their) participating institutions  (collectively  "Participants") shall
         maintain a book-entry  registration and transfer system with respect to
         ownership of beneficial  interests in the Bonds of Series BBB, CCC, and
         DDD (the "Book-Entry System").

              (b) The Bonds of Series  BBB,  CCC,  and DDD,  initially  shall be
         issued  in  the  form  of  a  separate,  single,  authenticated,  fully
         registered  bond for each such series (each a "Global  Debt  Security")
         which  (i)  need  not be in the  form  of a  lithographed  or  engraved
         certificate,  but may be  typewritten  or printed on ordinary  paper or
         such paper as the Trustee may reasonably request,  (ii) shall represent
         and be  denominated  in an  amount  equal  to  100%  of  the  aggregate
         principal  amount  of  the  Bonds  of  Series  BBB,  CCC,  or  DDD  (as
         applicable)  issued under this Supplemental  Indenture,  (iii) shall be
         executed by the Company and  authenticated by the Trustee in accordance
         with the provisions of the  Indenture,  (iv) shall be registered in the
         name of DTC or its  nominee,  and  delivered to DTC or its nominee or a
         custodian  therefor,  and (v) shall contain the following legend on the
         face thereof:

                       Unless this  certificate  is presented  by an  authorized
                       representative  of The Depository  Trust  Company,  a New
                       York  corporation  ("DTC"),  to  issuer  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  holder
                       hereof, Cede & Co., has an interest herein.

         Unless  and  until it is  exchanged  in  whole or in part for  Bonds of
Series BBB,  CCC, or DDD (as  applicable)  in  definitive  certificated  form, a
Global Debt Security  representing  the Bonds of a particular  Series may not be
transferred  except as a whole by DTC to a nominee of DTC or by a nominee of DTC
to DTC or another  nominee of DTC or by DTC or any such  nominee to a  successor
securities depository or a nominee of any such successor securities depository.

                  (c) The  Trustee  and the  Company may treat Cede & Co. or its
         nominee,  or any successor  securities  depository  or nominee  thereof
         (collectively, the "Depository") as the sole and exclusive owner of the
         Bonds of  Series  BBB,  CCC,  and DDD,  registered  in its name for the
         purposes of payment of the principal or redemption price of or interest
         on the Bonds of Series  BBB,  CCC, or DDD (as  applicable),  giving any
         notice  permitted  or  required  to be given to holders of the Bonds of
         Series BBB,  CCC, or DDD (as  applicable),  under the Indenture or this
         Supplemental Indenture, registering the transfer of the Bonds of Series
         BBB, CCC, and DDD, obtaining any consent or other action to be taken by
         holders of the Bonds of Series BBB,  CCC, or DDD (as  applicable),  and
         for all other  purposes  whatsoever  and  neither  the  Trustee nor the
         Company  shall be affected by any notice to the  contrary.  Neither the
         Company nor the Trustee nor any  registrar  nor any paying  agent shall
         have any  responsibility  or obligation to any Participant,  any person
         claiming a  beneficial  ownership  interest in the Bonds of Series BBB,
         CCC,  or DDD (as  applicable)  under or through the  Depository  or any
         Participant, or any other person which is not shown on the registration
         books as being a holder  of the Bonds of Series  BBB,  CCC,  or DDD (as
         applicable) with respect to (i) the accuracy of any records  maintained
         by  the  Depository  or  any  Participant;  (ii)  the  payment  by  the
         Depository to any Participant of any amount in respect of the principal
         or redemption  price of or interest on the Bonds of Series BBB, CCC, or
         DDD (as applicable);  (iii) the payment by any Participant to any owner
         of a beneficial  ownership interest in the Bonds of Series BBB, CCC, or
         DDD (as applicable),  in respect of the principal of or interest on the
         Bonds of Series BBB, CCC, or DDD (as applicable) or (iv) any consent or
         other  action taken by the  Depository  as owner of the Bonds of Series
         BBB, CCC, or DDD (as  applicable).  The Trustee shall pay all principal
         of  and  interest  on  the  Bonds  of  Series  BBB,  CCC,  or  DDD  (as
         applicable),  only to or upon the  order of the  registered  holder  or
         holders of the Bonds of Series  BBB,  CCC, or DDD (as  applicable),  as
         shown on the  registration  books, and all such payments shall be valid
         and effective to fully satisfy and discharge the Company's  obligations
         with respect to the  principal or  redemption  price of and interest on
         the Bonds of Series BBB, CCC, or DDD (as applicable),  to the extent of
         the sum or sums so paid.  No person other than a holder of the Bonds of
         Series BBB, CCC, or DDD (as  applicable),  as shown on the registration
         books of DTC,  shall  receive  an  authenticated  Bond  evidencing  the
         obligation  of the  Company  to make  payment of the  principal  of and
         interest  on the Bonds of Series  BBB,  CCC,  and DDD,  pursuant to the
         Indenture and this Supplemental Indenture.  Upon delivery by DTC to the
         Trustee of  written  notice to the effect  that DTC has  determined  to
         substitute  a new nominee for Cede & Co, and subject to the  provisions
         of the  Indenture  and this  Supplemental  Indenture,  the word "Cede &
         Co.", as used in this Supplemental  Indenture,  shall refer to each new
         nominee of DTC.

              (d) In the event that after the  occurrence of an event of default
         that has not been cured or waived,  holders of a majority in  aggregate
         principal  amount of the  beneficial  interests  in the Bonds of Series
         BBB,  the  Bonds  of  Series  CCC,  or the  Bonds  of  Series  DDD  (as
         applicable),  as reflected in the books and records of the  Depository,
         notify the Trustee, through the Depository or any Participant, that the
         continuation  of  the  Book-Entry  System  is no  longer  in  the  best
         interests of such holders of beneficial  interests in the Bonds of such
         Series,  then the Trustee shall notify the  Depository and the Company,
         and the Depository  will notify the  Participants  of the  availability
         through the Depository of definitive certificated Bonds of such Series.
         In such event, the Company shall execute, and the Trustee, upon receipt
         of a written  order of the Company,  signed by its  President or a Vice
         President  and by its  Treasurer,  Assistant  Treasurer,  Secretary  or
         Assistant  Secretary (an "Issue  Order"),  for the  authentication  and
         delivery  of  definitive  certificated  Bonds of Series  BBB,  Bonds of
         Series CCC, and Bonds Series DDD (as applicable), will authenticate and
         deliver  Bonds of such Series in definitive  certificated  form, in any
         authorized  denominations,  all  pursuant  to  the  provisions  of  the
         Indenture, to the person or persons specified to the Trustee in writing
         by the Depository in the aggregate  principal  amount of the applicable
         Global Debt Security or Securities and in exchange for such Global Debt
         Security or Securities.

              (e) If at any time the Depository  notifies the Company that it is
         unwilling or unable to continue as  Depository  for the Bonds of Series
         BBB,  the Bonds of Series CCC, or the Bonds of Series DDD, or if at any
         time the Depository  shall no longer be registered as a clearing agency
         in good standing under the Securities Exchange Act of 1934, as amended,
         or other  applicable  statute or regulation,  the Company may appoint a
         successor  Depository  with respect to the Bonds of such  Series.  If a
         successor  Depository  for the Bonds of such Series is not appointed by
         the Company  within 90 days after the Company  receives  such notice or
         becomes  aware of such  condition,  the Company will  execute,  and the
         Trustee,  upon  receipt of an Issuer Order for the  authentication  and
         delivery  of  definitive  certificated  Bonds of Series  BBB,  Bonds of
         Series CCC, and Bonds of Series DDD (as applicable),  will authenticate
         and deliver  Bonds of such Series in definitive  certificated  form, in
         any  authorized  denominations,  all pursuant to the  provisions of the
         Indenture, to the person or persons specified to the Trustee in writing
         by the Depository in the aggregate  principal  amount of the applicable
         Global Debt Security or Securities and in exchange for such Global Debt
         Security or Securities.

              (f)  The  Company  may at any  time  and  in its  sole  discretion
         determine that the Bonds of Series BBB, the Bonds of Series CCC, or the
         Bonds of Series  DDD shall no longer be  represented  by a Global  Debt
         Security. In such event the Company will execute, and the Trustee, upon
         receipt  of an Issuer  Order for the  authentication  and  delivery  of
         definitive  certificated  Bonds of such Series,  will  authenticate and
         deliver  Bonds of Series BBB,  Bonds of Series CCC, and Bonds of Series
         DDD (as applicable) in definitive  certificated form, in any authorized
         denominations,  all pursuant to the provisions of the Indenture, to the
         person or persons specified to the Trustee in writing by the Depository
         in the  aggregate  principal  amount  of  the  applicable  Global  Debt
         Security and in exchange for such Global Debt Security or Securities.

               (g) Upon the exchange of a Global Debt  Security for the Bonds of
          Series  BBB,  the Bonds of Series  CCC,  or the Bonds of Series DDD in
          definitive  certificated  form,  in  authorized   denominations,   the
          applicable  Global Debt Security or  Securities  shall be cancelled by
          the Trustee.

              (h) Whenever the  Depository  requests the Company and the Trustee
         to do  so,  the  Trustee  and  the  Company  will  cooperate  with  the
         Depository in taking  appropriate action after reasonable notice to (i)
         make available one or more separate Global Debt  Securities  evidencing
         the Bonds of Series  BBB,  the  Bonds of  Series  CCC,  or the Bonds of
         Series DDD to any  Participant  having Bonds of such Series credited to
         its account at the Depository,  or (ii) arrange for another  Depository
         to  maintain   custody  of  the  Global  Debt  Security  or  Securities
         evidencing  the Bonds of Series  BBB,  the Bonds of Series  CCC, or the
         Bonds of Series DDD.

              (i) In  connection  with any notice or other  communication  to be
         provided  to  holders of the Bonds of Series  BBB,  the Bonds of Series
         CCC,  or the Bonds of Series DDD  pursuant  to the  Indenture  and this
         Supplemental  Indenture  by the Company or the Trustee  with respect to
         any consent or other action to be taken by holders of the Bonds of such
         Series, the Company or the Trustee, as the case may be, shall establish
         a record date for such consent or other action and give the  Depository
         notice of such record date not less than 15 calendar days in advance of
         such record date to the extent possible.  Such notice to the Depository
         shall be given only so long as a Depository  or its nominee is the sole
         holder of the  Bonds of Series  BBB,  the Bonds of Series  CCC,  or the
         Bonds of Series DDD (as applicable).


         The Bonds of Series BBB, CCC, and DDD and the Trustee's  certificate of
each such series to be endorsed  thereon shall be substantially in the following
forms, respectively:



                                      - 1 -






                        (FORM OF FACE OF SERIES BBB BOND)

No. BBB-                                                           $............

                                PSI ENERGY, INC.
                      FIRST MORTGAGE BOND, SERIES BBB, 8%,
                                DUE JULY 15, 2009

[Unless this  certificate  is presented by an authorized  representative  of The
Depository Trust Company, a New York corporation ("DTC"), to issuer 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  holder  hereof,  Cede & Co.,  has an
interest herein.]1

         PSI  Energy,  Inc.,  an  Indiana  corporation  (hereinafter  called the
"Company"),  for value received,  hereby promises to pay to  ______________,  or
registered assigns, the principal sum of  _____________________________  Dollars
($ ) on the fifteenth day of July, 2009 and to pay interest on said sum from the
date  hereof,  until said  principal  sum is paid,  at the rate of 8% per annum,
payable  semi-annually  on the  fifteenth  day of January and July in each year.
Both the principal of and the interest on this bond shall be payable in any coin
or  currency  of the United  States of  America  which at the time of payment is
legal tender for the payment of public and private debts at the office or agency
of the Company in Plainfield, Indiana, or, at the option of the registered owner
hereof, at the office or agency of the Company in the Borough of Manhattan,  the
City of New York,  State of New York,  except that  interest on this bond may be
paid,  at the option of the Company,  by check or draft mailed to the address of
the person entitled thereto as it appears on the books of the Company maintained
for that purpose.

     REFERENCE IS MADE TO THE FURTHER  PROVISIONS  OF THIS BOND SET FORTH ON THE
REVERSE  HEREOF.  SUCH FURTHER  PROVISIONS  SHALL FOR ALL PURPOSES HAVE THE SAME
EFFECT AS THOUGH FULLY SET FORTH AT THIS PLACE.

         This  bond  shall  not be valid or become  obligatory  for any  purpose
unless  and  until it shall  have been  authenticated  by the  execution  by the
Trustee,  or its  successor  in trust under the  Indenture,  of the  certificate
endorsed hereon.

- --------
1 This  should be  included  only if the  Series  BBB Bonds are being  issued in
global form.


                                      - 2 -






         IN  WITNESS  WHEREOF,  PSI  Energy,  Inc.  has  caused  this bond to be
executed in its name by the manual or facsimile signature of its President or an
Executive Vice President or one of its Vice  Presidents,  and its corporate seal
or a  facsimile  thereof  to be hereto  affixed  and  attested  by the manual or
facsimile signature of its Secretary or one of its Assistant Secretaries.

Dated as of:

                                                     PSI ENERGY, INC.


                                 By.............................................

                                 ......................................President

ATTEST:


 .............................................

 ..............................Secretary



                                      - 3 -






                      (FORM OF REVERSE OF SERIES BBB BOND)

         This bond is one of the bonds of the  Company  issued  and to be issued
from time to time under and in  accordance  with and all secured by an indenture
of mortgage  or deed of trust,  dated  September  1, 1939,  from Public  Service
Company of Indiana  (predecessor  of the Company) to The First  National Bank of
Chicago, as Trustee, to which LaSalle National Bank is successor trustee, (which
indenture as amended by all supplemental  indentures is hereinafter  referred to
as the "Indenture").  Said Trustee or its successor in trust under the Indenture
is hereinafter  sometimes referred to as the "Trustee." Reference is hereby made
to the Indenture for a description of the property mortgaged and pledged and the
nature and extent of the security for said bonds. By the terms of the Indenture,
the bonds  secured  thereby are  issuable  in series  which may vary as to date,
amount,  date of  maturity,  rate of  interest  and in other  respects as in the
Indenture provided.

         This bond is one of a series  designated  as "PSI  Energy,  Inc.  First
Mortgage Bonds,  Series BBB, 8%, Due July 15, 2009" (hereinafter  referred to as
"Bonds of Series BBB") of the Company  issued under and secured by the Indenture
and  created by a  Fifty-Second  Supplemental  Indenture,  dated as of April 30,
1999, which also amends the Indenture.

         The  rights and  obligations  of the  Company  and of the  bearers  and
registered  owners of bonds may be modified  or amended  with the consent of the
Company by an affirmative  vote of the bearers or registered  owners entitled to
vote of at least  seventy-five per centum (75%) in principal amount of the bonds
then  outstanding at a meeting of bondholders  called for the purpose (and by an
affirmative  vote of the  bearers or  registered  owners  entitled to vote of at
least  seventy-five  per centum (75%) in principal amount of bonds of any series
affected by such  modification  or amendment in case one or more,  but less than
all,  series of bonds are so  affected),  all in the manner  and  subject to the
limitations set forth in the Indenture,  any consent by the bearer or registered
owner of any bond being  conclusive  and binding upon such bearer or  registered
owner  and  upon  all  future  bearers  or  registered   owners  of  such  bond,
irrespective  of whether  or not any  notation  of such  consent is made on such
bond; provided that no such modification or amendment shall, among other things,
extend the  maturity or reduce the amount of, or reduce the rate of interest on,
or otherwise modify the terms of the payment of the principal of, or interest or
premium (if any) on this bond, which obligations are absolute and unconditional,
or permit the  creation of any lien  ranking  prior to or equal with the lien of
the Indenture on any of the mortgaged property.

         The Bonds of Series BBB will be subject to redemption (the  "Make-Whole
Redemption")  at the option of the Company at any time in whole, or from time to
time in part,  until  maturity,  upon not  less  than 30 nor more  than 60 days'
notice,  at a redemption  price equal to the sum of (i) the principal  amount of
the Bonds of Series BBB being redeemed plus accrued and unpaid interest  thereon
to the redemption  date, and (ii) the Make-Whole  Amount (as defined below),  if
any, with respect to such Bonds of Series BBB.

         "Make-Whole Amount" means, in connection with any Make-Whole Redemption
of any Bonds of Series BBB, the excess, if any, of (i) the sum, as determined by
a Quotation  Agent (as defined  herein),  of the present values of the principal
amount of such Bonds of Series BBB, together with scheduled payments of interest
from the redemption  date to the stated  maturity of the Bonds of Series BBB, in
each case discounted to the redemption  date on a semi-annual  basis (assuming a
360-day year  consisting of twelve 30-day months) at the Adjusted  Treasury Rate
(as  defined  herein)  over  (ii) 100% of the  principal  amount of the Bonds of
Series BBB to be redeemed.

         "Adjusted Treasury Rate" means, with respect to any redemption date for
a Make-Whole Redemption,  the rate per annum equal to the semi-annual equivalent
yield  to  maturity  of the  Comparable  Treasury  Issue  (as  defined  herein),
calculated  using a price for the  Comparable  Treasury  Issue  (expressed  as a
percentage of its principal  amount) equal to the Comparable  Treasury Price (as
defined herein) for such redemption  date,  calculated on the third business day
preceding the redemption date, plus 0.15% (15 basis points).

         "Comparable  Treasury Issue" means the United States Treasury  security
selected by the Quotation Agent as having a maturity comparable to the remaining
term from the redemption  date to the stated maturity of the Bonds of Series BBB
that  would  be  utilized,  at the  time of  selection  and in  accordance  with
customary financial practice, in pricing new issues of corporate debt securities
of comparable maturity to the remaining term of the Bonds of Series BBB.

     "Quotation  Agent"  means the  Reference  Treasury  Dealer  selected by the
Trustee after consultation with the Company. "Reference Treasury Dealer" means a
primary U.S. Government securities dealer.

         "Comparable  Treasury Price" means, with respect to any redemption date
for a Make-Whole Redemption, (i) the average of the bid and asked prices for the
Comparable  Treasury  Issue  (expressed  in  each  case as a  percentage  of its
principal  amount) on the third business day preceding such redemption  date, as
set forth in the daily statistical  release  designated "H.15" (or any successor
release)  published by the Board of Governors of the Federal  Reserve  System or
(ii) if such  release (or any  successor  release) is not  published or does not
contain  such prices on such  business  day,  (A) the  average of the  Reference
Treasury Dealer Quotations for such redemption date, after excluding the highest
and lowest such  Reference  Treasury  Dealer  Quotations,  or (B) if the Trustee
obtains fewer than three such Reference Treasury Dealer Quotations,  the average
of such Quotations.

         "Reference  Treasury  Dealer  Quotations"  means,  with respect to each
Reference  Treasury Dealer and any redemption date for a Make-Whole  Redemption,
the average, as determined by the Trustee (after consultation with the Company),
of the bid and asked prices for the Comparable Treasury Issue (expressed in each
case as a percentage of its principal  amount)  quoted in writing to the Trustee
by such Reference Treasury Dealer at 5:00 p.m., New York City time, on the third
business day preceding such redemption date.

         Notice of any redemption by the Company will be mailed at least 30 days
but not more than 60 days before any redemption  date to each holder of Bonds of
Series  BBB to be  redeemed.  If less than all the Bonds of Series BBB are to be
redeemed at the option of the Company,  the Trustee shall select, in such manner
as it shall deem fair and appropriate, the Bonds of Series BBB of such series to
be redeemed in whole or in part.

         Unless the Company defaults in payment of the redemption  price, on and
after any redemption date,  interest will cease to accrue on the Bonds of Series
BBB or portions thereof called for redemption.

         In the  case of any of  certain  events  of  default  specified  in the
Indenture,  the  principal  of this bond may be  declared  or may become due and
payable  prior to the stated date of maturity  hereof in the manner and with the
effect provided in the Indenture.

         No  recourse  shall  be had  for the  payment  of the  principal  of or
interest on this bond,  or for any claim based  hereon,  or otherwise in respect
hereof or of the Indenture, to or against any incorporator, shareholder, officer
or director,  past,  present or future,  of the Company or of any predecessor or
successor company, either directly or through the Company or such predecessor or
successor  company,  under any constitution or statute or rule of law, or by the
enforcement  of any assessment or penalty,  or otherwise,  all such liability of
incorporators, shareholders, directors and officers being waived and released by
the  registered  owner hereof by the  acceptance of this bond and being likewise
waived and released by the terms of the Indenture.

         The Bonds of Series BBB are issuable  only in  registered  form without
coupons.  This bond is transferable by the registered owner hereof, in person or
by attorney duly  authorized,  at the  principal  office or place of business of
LaSalle  National  Bank,  the  Trustee,  or its  successor  in trust  under  the
Indenture, or, at the option of the registered owner, at the office or agency of
the  Company in the  Borough of  Manhattan,  the City of New York,  State of New
York,  upon the  surrender  and  cancellation  of this  bond,  and upon any such
transfer a new registered bond or bonds of the same series and maturity date and
for the same  aggregate  principal  amount will be issued to the  transferee  in
exchange herefor.

         The Bonds of Series BBB are issuable in the  denomination of $1,000 and
in such  multiples  thereof  as  shall  from  time to  time  be  determined  and
authorized  by the Board of Directors of the Company.  In the manner and subject
to  the  limitations  provided  in  the  Indenture,  Bonds  of  Series  BBB  are
exchangeable as between authorized denominations,  upon presentation thereof for
such  purpose  by the  registered  owner,  at the  principal  office or place of
business of LaSalle National Bank, the Trustee,  or its successor in trust under
the  Indenture,  or, at the  option of the  registered  owner,  at the office or
agency of the Company in the Borough of Manhattan,  the City of New York,  State
of New York.



                                      - 4 -






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


                         (FORM OF TRUSTEE'S CERTIFICATE)

                              TRUSTEE'S CERTIFICATE

         This  bond is one of the Bonds of the  Series  BBB  designated  therein
referred to and described in the within  mentioned  Indenture  and  Fifty-Second
Supplemental Indenture.

                                LASALLE NATIONAL BANK,
                                  AS TRUSTEE,


                                By.............................................
                                               Authorized Officer





                                      - 5 -






                        (FORM OF FACE OF SERIES CCC BOND)

No. CCC-                                                           $............

                                PSI ENERGY, INC.
                     FIRST MORTGAGE BOND, SERIES CCC, 8.85%,
                              DUE JANUARY 15, 2022

[Unless this  certificate  is presented by an authorized  representative  of The
Depository Trust Company, a New York corporation ("DTC"), to issuer 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  holder  hereof,  Cede & Co.,  has an
interest herein.]1

         PSI  Energy,  Inc.,  an  Indiana  corporation  (hereinafter  called the
"Company"),  for value received,  hereby promises to pay to  ______________,  or
registered assigns, the principal sum of  _____________________________  Dollars
($ ) on the fifteenth day of January,  2022 and to pay interest on said sum from
the date  hereof,  until said  principal  sum is paid,  at the rate of 8.85% per
annum,  payable  semi-annually  on the fifteenth day of January and July in each
year.  Both the  principal  of and the interest on this bond shall be payable in
any coin or  currency  of the  United  States  of  America  which at the time of
payment is legal  tender for the  payment  of public  and  private  debts at the
office or agency of the Company in Plainfield, Indiana, or, at the option of the
registered  owner hereof,  at the office or agency of the Company in the Borough
of Manhattan,  the City of New York, State of New York,  except that interest on
this bond may be paid, at the option of the Company, by check or draft mailed to
the  address  of the person  entitled  thereto as it appears on the books of the
Company maintained for that purpose.

     REFERENCE IS MADE TO THE FURTHER  PROVISIONS  OF THIS BOND SET FORTH ON THE
REVERSE  HEREOF.  SUCH FURTHER  PROVISIONS  SHALL FOR ALL PURPOSES HAVE THE SAME
EFFECT AS THOUGH FULLY SET FORTH AT THIS PLACE.

         This  bond  shall  not be valid or become  obligatory  for any  purpose
unless  and  until it shall  have been  authenticated  by the  execution  by the
Trustee,  or its  successor  in trust under the  Indenture,  of the  certificate
endorsed hereon.

- --------
1 This  should be  included  only if the  Series  CCC Bonds are being  issued in
global form.


                                      - 6 -






         IN  WITNESS  WHEREOF,  PSI  Energy,  Inc.  has  caused  this bond to be
executed in its name by the manual or facsimile signature of its President or an
Executive Vice President or one of its Vice  Presidents,  and its corporate seal
or a  facsimile  thereof  to be hereto  affixed  and  attested  by the manual or
facsimile signature of its Secretary or one of its Assistant Secretaries.

Dated as of:

                                 PSI ENERGY, INC.


                                 By.............................................

                                 ......................................President

ATTEST:


 .............................................

 ..............................Secretary



                                      - 7 -






                      (FORM OF REVERSE OF SERIES CCC BOND)

         This bond is one of the bonds of the  Company  issued  and to be issued
from time to time under and in  accordance  with and all secured by an indenture
of mortgage  or deed of trust,  dated  September  1, 1939,  from Public  Service
Company of Indiana  (predecessor  of the Company) to The First  National Bank of
Chicago, as Trustee, to which LaSalle National Bank is successor trustee, (which
indenture as amended by all supplemental  indentures is hereinafter  referred to
as the "Indenture").  Said Trustee or its successor in trust under the Indenture
is hereinafter  sometimes referred to as the "Trustee." Reference is hereby made
to the Indenture for a description of the property mortgaged and pledged and the
nature and extent of the security for said bonds. By the terms of the Indenture,
the bonds  secured  thereby are  issuable  in series  which may vary as to date,
amount,  date of  maturity,  rate of  interest  and in other  respects as in the
Indenture provided.

         This bond is one of a series  designated  as "PSI  Energy,  Inc.  First
Mortgage Bonds,  Series CCC, 8.85%, Due January 15, 2022" (hereinafter  referred
to as "Bonds of Series  CCC") of the  Company  issued  under and  secured by the
Indenture  and created by a  Fifty-Second  Supplemental  Indenture,  dated as of
April 30, 1999, which also amends the Indenture.

         The  rights and  obligations  of the  Company  and of the  bearers  and
registered  owners of bonds may be modified  or amended  with the consent of the
Company by an affirmative  vote of the bearers or registered  owners entitled to
vote of at least  seventy-five per centum (75%) in principal amount of the bonds
then  outstanding at a meeting of bondholders  called for the purpose (and by an
affirmative  vote of the  bearers or  registered  owners  entitled to vote of at
least  seventy-five  per centum (75%) in principal amount of bonds of any series
affected by such  modification  or amendment in case one or more,  but less than
all,  series of bonds are so  affected),  all in the manner  and  subject to the
limitations set forth in the Indenture,  any consent by the bearer or registered
owner of any bond being  conclusive  and binding upon such bearer or  registered
owner  and  upon  all  future  bearers  or  registered   owners  of  such  bond,
irrespective  of whether  or not any  notation  of such  consent is made on such
bond; provided that no such modification or amendment shall, among other things,
extend the  maturity or reduce the amount of, or reduce the rate of interest on,
or otherwise modify the terms of the payment of the principal of, or interest or
premium (if any) on this bond, which obligations are absolute and unconditional,
or permit the  creation of any lien  ranking  prior to or equal with the lien of
the Indenture on any of the mortgaged property.

         The Bonds of Series CCC will be subject to redemption (the  "Make-Whole
Redemption")  at the option of the Company at any time in whole, or from time to
time in part,  until  maturity,  upon not  less  than 30 nor more  than 60 days'
notice,  at a redemption  price equal to the sum of (i) the principal  amount of
the Bonds of Series CCC being redeemed plus accrued and unpaid interest  thereon
to the redemption  date, and (ii) the Make-Whole  Amount (as defined below),  if
any, with respect to such Bonds of Series CCC.

         "Make-Whole Amount" means, in connection with any Make-Whole Redemption
of any Bonds of Series CCC, the excess, if any, of (i) the sum, as determined by
a Quotation  Agent (as defined  herein),  of the present values of the principal
amount of such Bonds of Series CCC, together with scheduled payments of interest
from the redemption  date to the stated  maturity of the Bonds of Series CCC, in
each case discounted to the redemption  date on a semi-annual  basis (assuming a
360-day year  consisting of twelve 30-day months) at the Adjusted  Treasury Rate
(as  defined  herein)  over  (ii) 100% of the  principal  amount of the Bonds of
Series CCC to be redeemed.

         "Adjusted Treasury Rate" means, with respect to any redemption date for
a Make-Whole Redemption,  the rate per annum equal to the semi-annual equivalent
yield  to  maturity  of the  Comparable  Treasury  Issue  (as  defined  herein),
calculated  using a price for the  Comparable  Treasury  Issue  (expressed  as a
percentage of its principal  amount) equal to the Comparable  Treasury Price (as
defined herein) for such redemption  date,  calculated on the third business day
preceding the redemption date, plus 0.25% (25 basis points).

         "Comparable  Treasury Issue" means the United States Treasury  security
selected by the Quotation Agent as having a maturity comparable to the remaining
term from the redemption  date to the stated maturity of the Bonds of Series CCC
that  would  be  utilized,  at the  time of  selection  and in  accordance  with
customary financial practice, in pricing new issues of corporate debt securities
of comparable maturity to the remaining term of the Bonds of Series CCC.

     "Quotation  Agent"  means the  Reference  Treasury  Dealer  selected by the
Trustee after consultation with the Company. "Reference Treasury Dealer" means a
primary U.S. Government securities dealer.

         "Comparable  Treasury Price" means, with respect to any redemption date
for a Make-Whole Redemption, (i) the average of the bid and asked prices for the
Comparable  Treasury  Issue  (expressed  in  each  case as a  percentage  of its
principal  amount) on the third business day preceding such redemption  date, as
set forth in the daily statistical  release  designated "H.15" (or any successor
release)  published by the Board of Governors of the Federal  Reserve  System or
(ii) if such  release (or any  successor  release) is not  published or does not
contain  such prices on such  business  day,  (A) the  average of the  Reference
Treasury Dealer Quotations for such redemption date, after excluding the highest
and lowest such  Reference  Treasury  Dealer  Quotations,  or (B) if the Trustee
obtains fewer than three such Reference Treasury Dealer Quotations,  the average
of such Quotations.

         "Reference  Treasury  Dealer  Quotations"  means,  with respect to each
Reference  Treasury Dealer and any redemption date for a Make-Whole  Redemption,
the average, as determined by the Trustee (after consultation with the Company),
of the bid and asked prices for the Comparable Treasury Issue (expressed in each
case as a percentage of its principal  amount)  quoted in writing to the Trustee
by such Reference Treasury Dealer at 5:00 p.m., New York City time, on the third
business day preceding such redemption date.

         Notice of any redemption by the Company will be mailed at least 30 days
but not more than 60 days before any redemption  date to each holder of Bonds of
Series  CCC to be  redeemed.  If less than all the Bonds of Series CCC are to be
redeemed at the option of the Company,  the Trustee shall select, in such manner
as it shall deem fair and appropriate, the Bonds of Series CCC of such series to
be redeemed in whole or in part.

         Unless the Company defaults in payment of the redemption  price, on and
after any redemption date,  interest will cease to accrue on the Bonds of Series
CCC or portions thereof called for redemption.

         In the  case of any of  certain  events  of  default  specified  in the
Indenture,  the  principal  of this bond may be  declared  or may become due and
payable  prior to the stated date of maturity  hereof in the manner and with the
effect provided in the Indenture.

         No  recourse  shall  be had  for the  payment  of the  principal  of or
interest on this bond,  or for any claim based  hereon,  or otherwise in respect
hereof or of the Indenture, to or against any incorporator, shareholder, officer
or director,  past,  present or future,  of the Company or of any predecessor or
successor company, either directly or through the Company or such predecessor or
successor  company,  under any constitution or statute or rule of law, or by the
enforcement  of any assessment or penalty,  or otherwise,  all such liability of
incorporators, shareholders, directors and officers being waived and released by
the  registered  owner hereof by the  acceptance of this bond and being likewise
waived and released by the terms of the Indenture.

         The Bonds of Series CCC are issuable  only in  registered  form without
coupons.  This bond is transferable by the registered owner hereof, in person or
by attorney duly  authorized,  at the  principal  office or place of business of
LaSalle  National  Bank,  the  Trustee,  or its  successor  in trust  under  the
Indenture, or, at the option of the registered owner, at the office or agency of
the  Company in the  Borough of  Manhattan,  the City of New York,  State of New
York,  upon the  surrender  and  cancellation  of this  bond,  and upon any such
transfer a new registered bond or bonds of the same series and maturity date and
for the same  aggregate  principal  amount will be issued to the  transferee  in
exchange herefor.

         The Bonds of Series CCC are issuable in the  denomination of $1,000 and
in such  multiples  thereof  as  shall  from  time to  time  be  determined  and
authorized  by the Board of Directors of the Company.  In the manner and subject
to  the  limitations  provided  in  the  Indenture,  Bonds  of  Series  CCC  are
exchangeable as between authorized denominations,  upon presentation thereof for
such  purpose  by the  registered  owner,  at the  principal  office or place of
business of LaSalle National Bank, the Trustee,  or its successor in trust under
the  Indenture,  or, at the  option of the  registered  owner,  at the office or
agency of the Company in the Borough of Manhattan,  the City of New York,  State
of New York.



                                      - 8 -






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


                         (FORM OF TRUSTEE'S CERTIFICATE)

                              TRUSTEE'S CERTIFICATE

         This  bond is one of the Bonds of the  Series  CCC  designated  therein
referred to and described in the within  mentioned  Indenture  and  Fifty-Second
Supplemental Indenture.

                                 LASALLE NATIONAL BANK,
                                   AS TRUSTEE,


                                 By.............................................
                                                Authorized Officer



                                      - 9 -






                        (FORM OF FACE OF SERIES DDD BOND)

No. DDD-                                                           $............

                                PSI ENERGY, INC.
                     FIRST MORTGAGE BOND, SERIES DDD, 8.31%,
                              DUE SEPTEMBER 1, 2032

[Unless this  certificate  is presented by an authorized  representative  of The
Depository Trust Company, a New York corporation ("DTC"), to issuer 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  holder  hereof,  Cede & Co.,  has an
interest herein.]1

         PSI  Energy,  Inc.,  an  Indiana  corporation  (hereinafter  called the
"Company"),  for value received,  hereby promises to pay to  ______________,  or
registered assigns, the principal sum of  _____________________________  Dollars
($ ) on the first day of  September,  2032 and to pay  interest on said sum from
the date  hereof,  until said  principal  sum is paid,  at the rate of 8.31% per
annum,  payable  semi-annually  on the first day of March and  September in each
year.  Both the  principal  of and the interest on this bond shall be payable in
any coin or  currency  of the  United  States  of  America  which at the time of
payment is legal  tender for the  payment  of public  and  private  debts at the
office or agency of the Company in Plainfield, Indiana, or, at the option of the
registered  owner hereof,  at the office or agency of the Company in the Borough
of Manhattan,  the City of New York, State of New York,  except that interest on
this bond may be paid, at the option of the Company, by check or draft mailed to
the  address  of the person  entitled  thereto as it appears on the books of the
Company maintained for that purpose.

     REFERENCE IS MADE TO THE FURTHER  PROVISIONS  OF THIS BOND SET FORTH ON THE
REVERSE  HEREOF.  SUCH FURTHER  PROVISIONS  SHALL FOR ALL PURPOSES HAVE THE SAME
EFFECT AS THOUGH FULLY SET FORTH AT THIS PLACE.

         This  bond  shall  not be valid or become  obligatory  for any  purpose
unless  and  until it shall  have been  authenticated  by the  execution  by the
Trustee,  or its  successor  in trust under the  Indenture,  of the  certificate
endorsed hereon.

- --------
1 This  should be  included  only if the  Series  DDD Bonds are being  issued in
global form.


                                     - 10 -






         IN  WITNESS  WHEREOF,  PSI  Energy,  Inc.  has  caused  this bond to be
executed in its name by the manual or facsimile signature of its President or an
Executive Vice President or one of its Vice  Presidents,  and its corporate seal
or a  facsimile  thereof  to be hereto  affixed  and  attested  by the manual or
facsimile signature of its Secretary or one of its Assistant Secretaries.

Dated as of:

                                 PSI ENERGY, INC.


                                 By.............................................

                                 ......................................President

ATTEST:


 .............................................

 ..............................Secretary





                                     - 11 -






                      (FORM OF REVERSE OF SERIES DDD BOND)

         This bond is one of the bonds of the  Company  issued  and to be issued
from time to time under and in  accordance  with and all secured by an indenture
of mortgage  or deed of trust,  dated  September  1, 1939,  from Public  Service
Company of Indiana  (predecessor  of the Company) to The First  National Bank of
Chicago, as Trustee, to which LaSalle National Bank is successor trustee, (which
indenture as amended by all supplemental  indentures is hereinafter  referred to
as the "Indenture").  Said Trustee or its successor in trust under the Indenture
is hereinafter  sometimes referred to as the "Trustee." Reference is hereby made
to the Indenture for a description of the property mortgaged and pledged and the
nature and extent of the security for said bonds. By the terms of the Indenture,
the bonds  secured  thereby are  issuable  in series  which may vary as to date,
amount,  date of  maturity,  rate of  interest  and in other  respects as in the
Indenture provided.

         This bond is one of a series  designated  as "PSI  Energy,  Inc.  First
Mortgage Bonds, Series DDD, 8.31%, Due September 1, 2032" (hereinafter  referred
to as "Bonds of Series  DDD") of the  Company  issued  under and  secured by the
Indenture  and created by a  Fifty-Second  Supplemental  Indenture,  dated as of
April 30, 1999, which also amends the Indenture.

         The  rights and  obligations  of the  Company  and of the  bearers  and
registered  owners of bonds may be modified  or amended  with the consent of the
Company by an affirmative  vote of the bearers or registered  owners entitled to
vote of at least  seventy-five per centum (75%) in principal amount of the bonds
then  outstanding at a meeting of bondholders  called for the purpose (and by an
affirmative  vote of the  bearers or  registered  owners  entitled to vote of at
least  seventy-five  per centum (75%) in principal amount of bonds of any series
affected by such  modification  or amendment in case one or more,  but less than
all,  series of bonds are so  affected),  all in the manner  and  subject to the
limitations set forth in the Indenture,  any consent by the bearer or registered
owner of any bond being  conclusive  and binding upon such bearer or  registered
owner  and  upon  all  future  bearers  or  registered   owners  of  such  bond,
irrespective  of whether  or not any  notation  of such  consent is made on such
bond; provided that no such modification or amendment shall, among other things,
extend the  maturity or reduce the amount of, or reduce the rate of interest on,
or otherwise modify the terms of the payment of the principal of, or interest or
premium (if any) on this bond, which obligations are absolute and unconditional,
or permit the  creation of any lien  ranking  prior to or equal with the lien of
the Indenture on any of the mortgaged property.

         The Bonds of Series DDD will be subject to redemption (the  "Make-Whole
Redemption")  at the option of the Company at any time in whole, or from time to
time in part,  until  maturity,  upon not  less  than 30 nor more  than 60 days'
notice,  at a redemption  price equal to the sum of (i) the principal  amount of
the Bonds of Series DDD being redeemed plus accrued and unpaid interest  thereon
to the redemption  date, and (ii) the Make-Whole  Amount (as defined below),  if
any, with respect to such Bonds of Series DDD.

         "Make-Whole Amount" means, in connection with any Make-Whole Redemption
of any Bonds of Series DDD, the excess, if any, of (i) the sum, as determined by
a Quotation  Agent (as defined  herein),  of the present values of the principal
amount of such Bonds of Series DDD, together with scheduled payments of interest
from the redemption  date to the stated  maturity of the Bonds of Series DDD, in
each case discounted to the redemption  date on a semi-annual  basis (assuming a
360-day year  consisting of twelve 30-day months) at the Adjusted  Treasury Rate
(as  defined  herein)  over  (ii) 100% of the  principal  amount of the Bonds of
Series DDD to be redeemed.

         "Adjusted Treasury Rate" means, with respect to any redemption date for
a Make-Whole Redemption,  the rate per annum equal to the semi-annual equivalent
yield  to  maturity  of the  Comparable  Treasury  Issue  (as  defined  herein),
calculated  using a price for the  Comparable  Treasury  Issue  (expressed  as a
percentage of its principal  amount) equal to the Comparable  Treasury Price (as
defined herein) for such redemption  date,  calculated on the third business day
preceding the redemption date, plus 0.25% (25 basis points).

         "Comparable  Treasury Issue" means the United States Treasury  security
selected by the Quotation Agent as having a maturity comparable to the remaining
term from the redemption  date to the stated maturity of the Bonds of Series DDD
that  would  be  utilized,  at the  time of  selection  and in  accordance  with
customary financial practice, in pricing new issues of corporate debt securities
of comparable maturity to the remaining term of the Bonds of Series DDD.

     "Quotation  Agent"  means the  Reference  Treasury  Dealer  selected by the
Trustee after consultation with the Company. "Reference Treasury Dealer" means a
primary U.S. Government securities dealer.

         "Comparable  Treasury Price" means, with respect to any redemption date
for a Make-Whole Redemption, (i) the average of the bid and asked prices for the
Comparable  Treasury  Issue  (expressed  in  each  case as a  percentage  of its
principal  amount) on the third business day preceding such redemption  date, as
set forth in the daily statistical  release  designated "H.15" (or any successor
release)  published by the Board of Governors of the Federal  Reserve  System or
(ii) if such  release (or any  successor  release) is not  published or does not
contain  such prices on such  business  day,  (A) the  average of the  Reference
Treasury Dealer Quotations for such redemption date, after excluding the highest
and lowest such  Reference  Treasury  Dealer  Quotations,  or (B) if the Trustee
obtains fewer than three such Reference Treasury Dealer Quotations,  the average
of such Quotations.

         "Reference  Treasury  Dealer  Quotations"  means,  with respect to each
Reference  Treasury Dealer and any redemption date for a Make-Whole  Redemption,
the average, as determined by the Trustee (after consultation with the Company),
of the bid and asked prices for the Comparable Treasury Issue (expressed in each
case as a percentage of its principal  amount)  quoted in writing to the Trustee
by such Reference Treasury Dealer at 5:00 p.m., New York City time, on the third
business day preceding such redemption date.

         Notice of any redemption by the Company will be mailed at least 30 days
but not more than 60 days before any redemption  date to each holder of Bonds of
Series  DDD to be  redeemed.  If less than all the Bonds of Series DDD are to be
redeemed at the option of the Company,  the Trustee shall select, in such manner
as it shall deem fair and appropriate, the Bonds of Series DDD of such series to
be redeemed in whole or in part.

         Unless the Company defaults in payment of the redemption  price, on and
after any redemption date,  interest will cease to accrue on the Bonds of Series
DDD or portions thereof called for redemption.

         In the  case of any of  certain  events  of  default  specified  in the
Indenture,  the  principal  of this bond may be  declared  or may become due and
payable  prior to the stated date of maturity  hereof in the manner and with the
effect provided in the Indenture.

         No  recourse  shall  be had  for the  payment  of the  principal  of or
interest on this bond,  or for any claim based  hereon,  or otherwise in respect
hereof or of the Indenture, to or against any incorporator, shareholder, officer
or director,  past,  present or future,  of the Company or of any predecessor or
successor company, either directly or through the Company or such predecessor or
successor  company,  under any constitution or statute or rule of law, or by the
enforcement  of any assessment or penalty,  or otherwise,  all such liability of
incorporators, shareholders, directors and officers being waived and released by
the  registered  owner hereof by the  acceptance of this bond and being likewise
waived and released by the terms of the Indenture.

         The Bonds of Series DDD are issuable  only in  registered  form without
coupons.  This bond is transferable by the registered owner hereof, in person or
by attorney duly  authorized,  at the  principal  office or place of business of
LaSalle  National  Bank,  the  Trustee,  or its  successor  in trust  under  the
Indenture, or, at the option of the registered owner, at the office or agency of
the  Company in the  Borough of  Manhattan,  the City of New York,  State of New
York,  upon the  surrender  and  cancellation  of this  bond,  and upon any such
transfer a new registered bond or bonds of the same series and maturity date and
for the same  aggregate  principal  amount will be issued to the  transferee  in
exchange herefor.

         The Bonds of Series DDD are issuable in the  denomination of $1,000 and
in such  multiples  thereof  as  shall  from  time to  time  be  determined  and
authorized  by the Board of Directors of the Company.  In the manner and subject
to  the  limitations  provided  in  the  Indenture,  Bonds  of  Series  DDD  are
exchangeable as between authorized denominations,  upon presentation thereof for
such  purpose  by the  registered  owner,  at the  principal  office or place of
business of LaSalle National Bank, the Trustee,  or its successor in trust under
the  Indenture,  or, at the  option of the  registered  owner,  at the office or
agency of the Company in the Borough of Manhattan,  the City of New York,  State
of New York.



                                     - 12 -






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


                         (FORM OF TRUSTEE'S CERTIFICATE)

                              TRUSTEE'S CERTIFICATE

         This  bond is one of the Bonds of the  Series  DDD  designated  therein
referred to and described in the within  mentioned  Indenture  and  Fifty-Second
Supplemental Indenture.

                                 LASALLE NATIONAL BANK,
                                   AS TRUSTEE,


                                 By.............................................
                                               Authorized Officer




                                                 - 13 -






     Section 3. Each Bond of Series BBB,  CCC, and DDD issued prior to the first
interest  payment date shall be dated as of April 30, 1999, and otherwise  shall
be dated as provided in Section 1 of Article II of the Indenture.

     Section  4. All Bonds of Series  BBB shall be due and  payable  on July 15,
2009, and shall bear interest from the date thereof at the rate of 8% per annum,
payable  semi-annually  on the  fifteenth  day of January and July in each year,
commencing  July 15,  1999.  All Bonds of Series CCC shall be due and payable on
January 15, 2022,  and shall bear  interest from the date thereof at the rate of
8.85% per annum, payable  semi-annually on the fifteenth day of January and July
in each year, commencing July 15, 1999. All Bonds of Series DDD shall be due and
payable on September 1, 2032,  and shall bear  interest from the date thereof at
the rate of 8.31% per annum, payable semi-annually on the first day of March and
September in each year, commencing September 1, 1999.

         Section 5. Subject to agreements with or the rules of the Depository or
any  successor  book-entry  security  system or similar  system with  respect to
Global Securities, both the principal of and the interest on the Bonds of Series
BBB,  CCC, and DDD shall be payable in any coin or currency of the United States
of  America  which at the time of payment  is legal  tender  for the  payment of
public and private debts,  at the office or agency of the Company in Plainfield,
Indiana, or, at the option of the holder thereof, at the office or agency of the
Company in the Borough of  Manhattan,  the City of New York,  State of New York,
except that  interest on the Bonds of Series BBB,  CCC, and DDD may be paid,  at
the option of the Company, by check or draft mailed to the address of the person
entitled  thereto as it appears on the books of the Company  maintained for that
purpose.

     Section 6.  Definitive  Bonds of Series BBB, CCC, and DDD shall be issuable
in any denomination  which is a multiple of $1,000 numbered  consecutively  from
"BBB-1", "CCC-1", and "DDD-1", respectively, upward.

         All Bonds of Series  BBB,  CCC,  and DDD shall be executed on behalf of
the  Company  by the  manual  or  facsimile  signature  of its  President  or an
Executive  Vice  President or one of its Vice  Presidents and shall have affixed
thereto the seal of the Company or a facsimile thereof attested by the manual or
facsimile  signature of its  Secretary or one of its Assistant  Secretaries  and
shall be  authenticated  by the  execution  by the  Trustee  of the  certificate
endorsed on said bonds.

         No service  charge will be made by the Company for the  transfer or for
the  exchange  of Bonds of  Series  BBB,  CCC,  and DDD  except,  in the case of
transfer,  a charge  sufficient  to  reimburse  the Company for any tax or other
governmental charge payable in connection therewith.

         Pursuant  to  the  provisions  of  Section  11 of  Article  II  of  the
Indenture,  Bonds of Series BBB,  CCC, and DDD may be issued in temporary  form,
and if  temporary  bonds be  issued,  the  Company  shall,  with all  reasonable
dispatch,  at its own expense and without charge to the holders of the temporary
bonds,  prepare and execute  definitive  Bonds of Series BBB,  CCC,  and DDD and
exchange the temporary  bonds for such  definitive  bonds in the manner provided
for in  said  section,  provided,  however,  no  presentation  or  surrender  of
temporary  Bonds of Series BBB, CCC, and DDD shall be necessary in order for the
holders entitled to interest thereon to receive such interest.


                                   ARTICLE II.

                 ISSUANCE OF BONDS OF SERIES BBB, CCC, AND DDD.

          Section  1. An initial  issue of Bonds of Series BBB in the  aggregate
principal  amount not  exceeding  one  hundred  twenty-four  million six hundred
sixty-five thousand dollars ($124,665,000),  an initial issue of Bonds of Series
CCC in the aggregate  principal  amount not exceeding  sixty million  fifty-five
thousand dollars  ($60,055,000),  and an initial issue of Bonds of Series DDD in
the  aggregate  principal  amount not  exceeding  thirty-eight  million  dollars
($38,000,000),  may be executed by the Company and  delivered to the Trustee for
authentication,  and shall be  authenticated  and delivered by the Trustee to or
upon the order of the Company  (which  authentication  and  delivery may be made
without  awaiting  the filing or  recording  of this  Fifty-Second  Supplemental
Indenture),  upon  receipt  by the  Trustee  of the  resolutions,  certificates,
orders,  opinions and other instruments  required by the provisions of Section 2
of Article IV of the  Indenture  to be received by the Trustee as a condition to
the authentication and delivery by the Trustee of bonds pursuant to said Section
2.

     Section 2. Subject to the  limitations  provided in Section 24 of Article V
of the Indenture,  additional Bonds of Series BBB, CCC, and DDD may be issued by
the  Company  under the  provisions  of  Sections 2, 3 or 4 of Article IV of the
Indenture.


                                  ARTICLE III.

                              INDENTURE AMENDMENTS.

     Section 1. Article I of the  Indenture,  as heretofore  amended,  is hereby
further amended (i) by adding  immediately after  subdivision  "(91)" thereof an
additional subdivision numbered "(92)" and reading as follows:

          "(92) The term  'Fifty-Second  Supplemental  Indenture' shall mean the
         Fifty-Second  Supplemental  Indenture  executed  by the Company and the
         Trustee,  dated as of April 30,  1999,  supplementing  and amending the
         Indenture,  and the terms  'Bonds of Series  BBB'  shall  mean the 'PSI
         Energy, Inc. First Mortgage Bonds, Series BBB, 8%, Due July 15, 2009,',
         'Bonds of Series CCC' shall mean the 'PSI Energy,  Inc.  First Mortgage
         Bonds,  Series CCC, 8.85%, Due January 15, 2022,', and 'Bonds of Series
         BBB' shall mean the 'PSI Energy, Inc. First Mortgage Bonds, Series DDD,
         8.31%,   Due   September  1,  2032,',   created  by  the   Fifty-Second
         Supplemental Indenture."

     and (ii) by  changing  the  numbering  of the  present  subdivision  "(92)"
thereof to "(93)".

     Section 2. Article VII of the Indenture,  as heretofore  amended, is hereby
further amended by inserting therein immediately after Section 36 thereof, a new
section designated "Section 37" and reading as follows:

                  "Section  37.  Each of the Bonds of Series  BBB,  the Bonds of
         Series CCC,  and the Bonds of Series DDD will be subject to  redemption
         (the 'Make-Whole  Redemption') at the option of the Company at any time
         in whole, or from time to time in part,  until maturity,  upon not less
         than 30 nor more than 60 days' notice to the holders of such Series, at
         a redemption  price equal to the sum of (i) the principal amount of the
         Bonds of such Series being  redeemed,  plus accrued and unpaid interest
         thereon to the  redemption  date,  and (ii) the  Make-Whole  Amount (as
         defined below), if any, with respect to such Bonds.

                  'Make-Whole  Amount' means,  in connection with any Make-Whole
         Redemption of any Bonds of Series BBB, Bonds of Series CCC, or Bonds of
         Series DDD,  the excess,  if any,  of (i) the sum, as  determined  by a
         Quotation  Agent (as  defined  herein),  of the  present  values of the
         principal amount of such Bonds being redeemed,  together with scheduled
         payments of interest from the redemption date to the stated maturity of
         such  Bonds,  in  each  case  discounted  to the  redemption  date on a
         semi-annual  basis (assuming a 360-day year consisting of twelve 30-day
         months) at the  Adjusted  Treasury  Rate (as defined  herein) over (ii)
         100% of the  principal  amount of the Bonds of Series BBB, the Bonds of
         Series CCC, or the Bonds of Series DDD (as applicable) to be redeemed.

                  'Adjusted Treasury Rate' means, with respect to any redemption
         date for a  Make-Whole  Redemption,  the rate  per  annum  equal to the
         semi-annual  equivalent  yield to maturity of the  Comparable  Treasury
         Issue (as defined herein),  calculated using a price for the Comparable
         Treasury  Issue  (expressed as a percentage  of its  principal  amount)
         equal to the  Comparable  Treasury  Price (as defined  herein) for such
         redemption  date,  calculated  on the third  business day preceding the
         redemption  date,  plus 0.15% (15 basis points) for the Bonds of Series
         BBB and plus  0.25% (25 basis  points)  for the Bonds of Series CCC and
         Bonds of Series DDD.

               'Comparable  Treasury  Issue'  means the United  States  Treasury
          security  selected  by  the  Quotation  Agent  as  having  a  maturity
          comparable  to the  remaining  term  from the  redemption  date to the
          stated maturity of the Bonds of Series BBB, CCC, and DDD that would be
          utilized,  at the time of selection and in accordance  with  customary
          financial practice, in pricing new issues of corporate debt securities
          of comparable  maturity to the  remaining  term of the Bonds of Series
          BBB, CCC, and DDD.

               'Quotation Agent' means the Reference Treasury Dealer selected by
          the Trustee after consultation with the Company.  'Reference  Treasury
          Dealer' means a primary U.S. Government securities dealer.

                  'Comparable   Treasury  Price'  means,  with  respect  to  any
         redemption date for a Make-Whole Redemption, (i) the average of the bid
         and asked prices for the Comparable  Treasury Issue  (expressed in each
         case as a percentage of its principal amount) on the third business day
         preceding such redemption  date, as set forth in the daily  statistical
         release  designated 'H.15' (or any successor  release) published by the
         Board  of  Governors  of the  Federal  Reserve  System  or (ii) if such
         release (or any successor release) is not published or does not contain
         such prices on such  business  day,  (A) the  average of the  Reference
         Treasury Dealer  Quotations for such redemption  date,  after excluding
         the highest and lowest such Reference  Treasury Dealer  Quotations,  or
         (B) if the Trustee  obtains  fewer than three such  Reference  Treasury
         Dealer Quotations, the average of such Quotations.

                  'Reference  Treasury Dealer Quotations' means, with respect to
         each Reference Treasury Dealer and any redemption date for a Make-Whole
         Redemption,   the  average,   as  determined  by  the  Trustee   (after
         consultation  with the  Company),  of the bid and asked  prices for the
         Comparable  Treasury  Issue  (expressed in each case as a percentage of
         its  principal  amount)  quoted  in  writing  to the  Trustee  by  such
         Reference  Treasury  Dealer at 5:00 p.m.,  New York City  time,  on the
         third business day preceding such redemption date.

               Notice of any  redemption  by the Company will be mailed at least
          30 days but not more than 60 days before any  redemption  date to each
          holder of Bonds of Series BBB,  CCC, and DDD to be  redeemed.  If less
          than all the Bonds of Series  BBB,  the  Bonds of Series  CCC,  or the
          Bonds of Series DDD (as  applicable)  are to be redeemed at the option
          of the Company,  the Trustee shall select,  in such manner as it shall
          deem  fair and  appropriate,  the Bonds of  Series  BBB,  the Bonds of
          Series CCC, or the Bonds of Series DDD (as  applicable) to be redeemed
          in whole or in part.

               Unless the Company  defaults in payment of the redemption  price,
          on and after any redemption date, interest will cease to accrue on the
          Bonds of Series  BBB,  CCC,  and DDD or  portions  thereof  called for
          redemption.

                  The Company shall indemnify and hold harmless the Trustee from
         any  and  all  losses,  costs,  damages,   expenses,   fees  (including
         attorneys'  fees),  court  costs,  judgments,  penalties,  obligations,
         suits,   disbursements   and  liabilities  of  any  kind  or  character
         whatsoever  which  may at any  time be  imposed  upon,  incurred  by or
         asserted  against the Trustee by reason of or arising out of or caused,
         directly or  indirectly  by any act or  omission  of the  Trustee  with
         respect to the  foregoing  Section  37,  including  without  limitation
         selection of any  Reference  Treasury  Dealer or  determination  of any
         Reference Treasury Dealer Quotations,  except for such that would arise
         out of the willful  misconduct  or gross  negligence of the Trustee and
         except for costs and  expenses  arising in the  ordinary  course of the
         Trustee's business.."

     Section 3. Article IX of the Indenture,  "Maintenance  and Renewal Fund and
Sinking Fund Provisions" as heretofore and hereby amended or supplemented  shall
not  apply to the  Bonds of  Series  BBB,  CCC,  and DDD or to any  subsequently
created  series  of bonds  from and  after  the date on which no series of bonds
created under the  Indenture  prior to the Bonds of Series BBB, CCC, and DDD are
outstanding.

     Section 4.  Section  22 of Article V of the  Indenture  as  heretofore  and
hereby amended or supplemented which, among other things, requires an inspection
of the mortgaged property every two years by an independent engineer,  shall not
apply to the Bonds of Series BBB,  CCC, and DDD or to any  subsequently  created
series  of bonds,  from and  after the date in which no series of bonds  created
under  the  Indenture  prior  to the  Bonds  of  Series  BBB,  CCC,  and DDD are
outstanding.

     Section 5. The Company reserves the right,  without consent or other action
by the holders of the Bonds of Series BBB,  CCC, and DDD or of any  subsequently
created  series of bonds,  to amend the  Indenture,  as  heretofore  and  hereby
amended or supplemented, at any time after all bonds of any series created prior
to the Bonds of Series BBB,  CCC,  and DDD are no longer  outstanding  under the
Indenture, as follows:

          (a) by  substituting  for the words "in  principal  amount not greater
     than  sixty per centum  (60%) of " in  Section 3 of Article IV thereof  the
     following:

               "in principal  amount not greater than  sixty-six and  two-thirds
          per centum (66-2/3%) of ".

          (b) by substituting for the words "shall exceed sixty per centum (60%)
     of the value of bondable  property so  acquired"  in Section 9 of Article V
     thereof the following:

               "shall exceed  sixty-six and two-thirds  per centum  (66-2/3%) of
          the value of bondable property so acquired".

          (c) by  substituting  for the words "shall be deemed to be paid within
     the  meaning of this  article;  provided,  that the date for the payment or
     redemption  of such  bonds  shall be not more than one (1) year  after such
     moneys  shall  have been so set apart or paid." in the first  paragraph  of
     Article XIV thereof the following:

               "shall be deemed to be paid within the meaning of this article.".

          (d) by  substituting  for the words "with the consent of holders of at
     least  seventy-five  per centum (75%) in aggregate  principal amount of the
     bonds at the time  outstanding;" in sub-section (a) of Section 3 of Article
     XVIII thereof the following:

               "with the consent of holders of at least sixty-six and two-thirds
          per centum (66-2/3%) in aggregate principal amount of the bonds at the
          time outstanding;".

          (e) by  substituting  for the words  "holders (or persons  entitled to
     vote the bonds) of not less than seventy-five per centum (75%) in aggregate
     principal  amount of the bonds entitled to be voted" in sub-section  (l) of
     Section 3 of Article XVIII thereof the following:

               "holders (or persons entitled to vote the bonds) of not less than
          sixty-six and two-thirds per centum  (66-2/3%) in aggregate  principal
          amount of the bonds entitled to be voted".

          (f) by  substituting  for the words  "holders (or persons  entitled to
     vote the  bonds) of at least  seventy-five  per centum  (75%) in  principal
     amount of the bonds outstanding" in sub-section (m) of Section 3 of Article
     XVIII thereof the following:

               "holders  (or  persons  entitled  to vote the  bonds) of at least
          sixty-six and two-thirds per centum  (66-2/3%) in principal  amount of
          the bonds outstanding".


                                   ARTICLE IV.

                             CONCERNING THE TRUSTEE.

     The Trustee hereby accepts the trusts hereby declared and agrees to perform
the same upon the terms and conditions in the Indenture and in this Fifty-Second
Supplemental  Indenture set forth.  The Trustee shall not be  responsible in any
manner  whatsoever  for or in respect of the  validity  or  sufficiency  of this
Fifty-Second  Supplemental  Indenture or the due execution hereof by the Company
or for or in respect of the recitals contained herein, all of which recitals are
made by the  Company  solely.  In  general,  each and every  term and  condition
contained  in Article  XVII of the  Indenture  shall apply to this  Fifty-Second
Supplemental Indenture.




                                     - 14 -






                                   ARTICLE V.

                            MISCELLANEOUS PROVISIONS.

     Section 1.  Wherever in the original  Indenture or in any of the  fifty-two
supplemental  indentures  thereto reference is made to any article or section of
the original Indenture,  such reference shall be deemed to refer to such article
or section as amended by such supplemental indentures.

         Section 2. Upon the execution and delivery hereof,  the Indenture shall
thereupon be deemed to be amended as hereinabove set forth as fully and with the
same effect as if the  amendments  made  hereby  were set forth in the  original
Indenture  and each of the  fifty-two  supplemental  indentures to the Indenture
shall  henceforth be read,  taken and construed as one and the same  instrument;
but such  amendments  shall not operate so as to render  invalid or improper any
action  heretofore  taken  under the  original  Indenture  or said  supplemental
indentures.

         Section  3. All the  covenants,  stipulations  and  agreements  in this
Fifty-Second  Supplemental Indenture contained are and shall be for the sole and
exclusive  benefit of the parties hereto,  their successors and assigns,  and of
the holders from time to time of the bonds.

     Section 4. The table of  contents  to, and the  headings  of the  different
articles  of,  this  Fifty-Second   Supplemental   Indenture  are  inserted  for
convenience  of  reference,  and  are  not to be  taken  to be any  part  of the
provisions hereof, nor to control or affect the meaning,  construction or effect
of the same.

     Section 5. This Fifty-Second  Supplemental  Indenture may be simultaneously
executed  in any  number  of  counterparts,  and  all  such  counterparts  shall
constitute but one and the same instrument.

         Section 6.  Whenever a payment of  principal  or interest in respect of
the Bonds of Series BBB,  CCC,  and DDD are due on any day other than a business
day (as  hereinafter  defined),  such  payment  shall be  payable  on the  first
business day next following such date, and, in the case of a principal  payment,
interest on such  principal  payment shall accrue to the date of such  principal
payment. For the purposes of this Section 6 the term business day shall mean any
day other than a day on which the Trustee is authorized by law to close.





                                     - 15 -






         IN WITNESS WHEREOF, said PSI Energy, Inc. has caused this instrument to
be executed in its corporate name by its President or one of its Vice Presidents
and to be attested by its Secretary or one of its Assistant Secretaries and said
LaSalle National Bank has caused this instrument to be executed in its corporate
name  by one of its  First  Vice  Presidents  and to be  attested  by one of its
Assistant Secretaries, in several counterparts, all as of the day and year first
above written.

                                             PSI ENERGY, INC.


(CORPORATE SEAL)                             By ________________________
                                                   William L. Sheafer
                                              Vice President and Treasurer
ATTEST:

- ----------------------
John E. Polley, Assistant Secretary

Signed and delivered by PSI Energy, Inc.
   in the presence of:

- ---------------------------
                           Witness

 ---------------------------
                           Witness

                                                     LASALLE NATIONAL BANK


(CORPORATE SEAL)                              By ________________________
                                                      Sarah H. Webb
                                                   First Vice President
 ATTEST:

- ----------------------
Russell C. Bergman, Assistant Secretary

Signed and delivered by LaSalle National Bank in the presence of:

- ---------------------------
                           Witness

- ---------------------------
                           Witness


                                     - 16 -







STATE OF OHIO                   )
                                ) ss:
COUNTY OF HAMILTON                                        )


         BE IT REMEMBERED,  that on this ___ day of April,  1999, before me, the
undersigned,  a notary  public in and for the County and State  aforesaid,  duly
commissioned and qualified,  personally  appeared William L. Sheafer and John E.
Polley, personally known to me to be the same persons whose names are subscribed
to the foregoing instrument, and personally known to me to be the Vice President
and Treasurer, and an Assistant Secretary, respectively, of PSI Energy, Inc., an
Indiana  corporation,  and  acknowledged  that they  signed and  delivered  said
instrument as their free and voluntary act as such Vice President and Treasurer,
and Assistant Secretary, respectively, and as the free and voluntary act of said
PSI Energy Inc.,  for the uses and purposes  therein set forth;  in pursuance of
the power and authority  granted to them by resolution of the Board of Directors
of said Company.

         IN WITNESS WHEREOF, I have hereunto set my hand and affixed my notarial
seal the day and year aforesaid.

(NOTARIAL SEAL)


                                                     -------------------------
                                                              Notary Public


My commission expires _________________.

County of residence: Hamilton




                                     - 17 -






STATE OF ILLINOIS               )
                                ) ss:
COUNTY OF COOK                  )


         BE IT REMEMBERED,  that on this ____ day of April, 1999, before me, the
undersigned,  a notary  public in and for the County and State  aforesaid,  duly
commissioned  and  qualified,  personally  appeared Sarah H. Webb and Russell C.
Bergman,  personally  known  to  me to be  the  same  persons  whose  names  are
subscribed to the foregoing instrument, and personally known to me to be a First
Vice President and an Assistant  Secretary,  respectively,  of LaSalle  National
Bank, a national  banking  association,  and  acknowledged  that they signed and
delivered  said  instrument  as their free and  voluntary act as such First Vice
President and Assistant Secretary,  respectively,  and as the free and voluntary
act of said LaSalle  National Bank, for the uses and purposes therein set forth;
in  pursuance of the power and  authority  granted to them by the bylaws of said
association.

         IN WITNESS WHEREOF, I have hereunto set my hand and affixed my notarial
seal the day and year aforesaid.

(NOTARIAL SEAL)


                                                     -------------------------
                                                              Notary Public


My commission expires _________________.

County of residence: Cook




                                     - 18 -