<Page>


                                                                    Exhibit 4(b)


                  FORM OF FIXED-RATE UNSECURED DEBT SECURITIES

                                      FRONT
REGISTERED                                                           REGISTERED

No. FXR ___

CUSIP

                       BALTIMORE GAS AND ELECTRIC COMPANY

              INCORPORATED UNDER THE LAWS OF THE STATE OF MARYLAND

                            UNSECURED DEBT SECURITIES

[If this Note is registered in the name of The Depository Trust Company (the
"Depositary") (55 Water Street, New York, New York) or its nominee, this Note
may not be transferred except as a whole by the Depositary to a nominee of the
Depositary or by a nominee of the Depositary to the Depositary or another
nominee of the Depositary or by the Depositary or any such nominee to a
successor Depositary or a nominee of such successor Depositary unless and until
this Note is exchanged in whole or in part for Notes in definitive form. Unless
this certificate is presented by an authorized representative of the Depositary
to the Company or its agent for registration of transfer, exchange or payment,
and any certificate issued is registered in the name of Cede & Co. or such other
name as requested by an authorized representative of the Depositary and any
payment is made to Cede & Co., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR
VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL since the registered owner
hereof, Cede & Co. has an interest herein.]

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<Table>
<S>                          <C>
PRINCIPAL AMOUNT:            _____________________

INTEREST RATE:               ______________________

STATED MATURITY:             ______________________

ORIGINAL ISSUE DATE:         ______________________

</Table>


<Page>


ISSUE PRICE:                 ______________________

<Table>
<Caption>
             REDEEMABLE
         AT THE OPTION OF THE                     REDEMPTION PRICES
         COMPANY ON OR AFTER                   (% OF PRINCIPAL AMOUNT)
         -------------------                   -----------------------
<S>                                        <C>

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

</Table>

                  [IF FLOATING RATE, BASIS TO BE PRINTED HERE]
                  --------------------------------------------

<Table>
<Caption>
        SUBJECT TO REPURCHASE
           AT THE OPTION                             REPURCHASE PRICES
          OF THE HOLDER ON                        (% OF PRINCIPAL AMOUNT)
          ----------------                        -----------------------
<S>                                        <C>

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

</Table>

[Remarketing provisions, if any, to be included here]
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               Baltimore Gas and Electric Company, a Maryland corporation
(herein called the "Company", which term includes any successor corporation
under the Indenture, as hereinafter defined), for value received, promises to
pay to Cede & Co. or its registered assigns, the principal sum of
_________________________________________________________ DOLLARS on the Stated
Maturity shown above and to pay interest on said principal sum from the Original
Issue Date shown above if interest has not been paid on this Note or from the
most recent Interest Payment Date for which interest has been paid or duly
provided for, at the fixed rate per annum shown above, semi-annually on ___ and
___ (the "Interest Payment Date(s)") of each year until the Stated Maturity or
upon redemption or repurchase of this Note. Each payment of interest payable on
each Interest Payment Date and at Stated Maturity or, if applicable, upon
redemption or repurchase shall include interest to, but excluding the relevant
Interest Payment Date and the date of Stated Maturity or redemption,
respectively. Said interest shall be computed on the basis of a 360-day year of
twelve 30-day months. In the event this Note is issued between a Record Date
(the ___ and ___ next preceding the ___ and ___ Interest Payment Dates) and an
Interest Payment Date or on an Interest Payment Date, the first day that
interest shall be payable will be on the Interest Payment Date following the
next succeeding Record Date. In the event of a default in the payment of
interest, interest will be payable as provided in that certain Indenture dated
as of July 1, 1985, as supplemented by the Supplemental Indentures dated as of
October 1, 1987, and January 26, 1993, respectively (the "Indenture"), by and
between the Company and The Bank of New York (successor to Mercantile-Safe
Deposit and Trust Company), a corporation duly organized and existing under the
laws of the State of New York , as Trustee (herein called the "Trustee," which
term includes any successor Trustee under the Indenture).


                                       2
<Page>


               Pursuant to the provisions of the Indenture, the Company will
maintain an agency at The Bank of New York in The City of New York, New York
(the "Bank"), or at such other agencies as may from time to time be designated,
where the Notes may be presented for payment, for registration of transfer and
exchange, and where notices or demands to, or upon, the Company may be served.

               The interest so payable on any ___ or ___ will, subject to
certain exceptions provided in the Indenture, be paid to the person in whose
name this Note is registered at the close of business on the Record Date for
such Interest Payment Date, which shall be the ___ and ___ next preceding the
___ and ___ Interest Payment Dates; provided, however, that interest payable at
Stated Maturity or, if applicable, upon redemption or repurchase, shall be
payable to the person to whom principal shall be payable. Payment of the
principal of and interest on this Note will be made at the Bank in U.S. dollars;
provided, however, that payments of interest (other than any interest payable at
Stated Maturity or upon redemption or repurchase) may be made at the option of
the Company (i) by checks mailed to the addresses of the persons entitled
thereto as such addresses shall appear in the register of the Notes or (ii) by
wire transfer to persons who are holders of record at such other addresses that
have been filed with the Bank on or prior to the Record Date.

               Payment of the principal, premium, if any, and interest payable
at Stated Maturity, or, if applicable, upon redemption or repurchase, on this
Note will be made in immediately available funds at the request of the holder
provided that this Note is presented to the Bank in time for the Bank to make
such payments in such funds in accordance with its normal procedures.

               Reference is made to the further provisions of this Note set
forth on the reverse hereof, which shall have the same effect as though fully
set forth at this place.

               Unless the certificate of authentication hereon has been executed
by or on behalf of the Trustee or a duly designated authentication agent by
manual signature, this Note shall not be entitled to any benefit under said
Indenture, or be valid or obligatory for any purpose.

               IN WITNESS WHEREOF, Baltimore Gas and Electric Company has caused
this instrument to be executed in its corporate name with the manual or
facsimile signature of its President or a Vice President and a facsimile of its
corporate seal to be imprinted hereon, attested by the manual or facsimile
signature of its Secretary or an Assistant Secretary.

Dated:

BALTIMORE GAS AND ELECTRIC COMPANY

By:               ____________________
                      President

ATTEST:           ____________________       [SEAL]
                      Secretary


                                       3
<Page>


CERTIFICATE OF AUTHENTICATION
This is one of the Securities of the
series designated herein issued under
the Indenture described herein.

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

Dated: ____________

THE BANK OF NEW YORK

By:    ____________________
       Authorized Signatory


                                       4
<Page>


                  FORM OF FIXED-RATE UNSECURED DEBT SECURITIES


                                    (REVERSE)

                       BALTIMORE GAS AND ELECTRIC COMPANY

                            UNSECURED DEBT SECURITIES

               This Note is one of a duly authorized issue of debt securities
(the "Securities") of the Company, of a series designated as its unsecured debt
securities (herein called the "Notes"), issued and to be issued under the
Indenture, to which Indenture and all relevant indentures supplemental thereto
reference is hereby made for a statement of the respective rights, obligations,
duties and immunities thereunder of the Company, the Trustee, the Bank and the
Securityholders and the terms upon which the Notes are, and are to be,
authenticated and delivered. The Securities, of which the Notes constitute a
series, may be issued in one or more series, which different series may be
issued in various aggregate principal amounts, may mature at different times,
may bear interest at different rates, may be subject to different covenants and
Events of Default and may otherwise vary as in the Indenture provided. All
capitalized terms not otherwise defined herein shall have the definitions
assigned to them in the Indenture.

               [This Note may not be redeemed by the Company prior to Stated
Maturity unless otherwise set forth on the face hereof. Notwithstanding Section
4.03 of the Indenture, pursuant to Section 4.01 thereof, and if so indicated on
the face of this Note, this Note may be redeemed at the option of the Company on
any date on or after the date set forth on the face hereof in whole or in part
in increments of $1,000, at a redemption price or prices designated on the face
hereof to be redeemed together with interest thereon payable to the date fixed
for redemption. This Note may be so redeemed in whole or in part whether or not
other Notes of the same series are redeemed.]* To be modified as appropriate

               [Notice of redemption by the Company will be given by the Company
by mail to holders of the Notes to be redeemed, not less than 30 nor more than
60 days prior to the date fixed for redemption, all as provided in the
Indenture. The Bank may carry out the responsibilities to be performed by the
Trustee required by Article Four of the Indenture.] * To be modified as
appropriate

        [The Company is not required to repurchase Notes from holders prior to
Stated Maturity unless otherwise set forth on the face hereof. If so indicated
on the face hereof, this Note may be repurchased by the Company at the option of
the holder on the dates and at the prices designated thereon, in whole or in
part in increments of $1,000, together with interest payable to the repurchase
date. For book-entry notes, unless otherwise specified on the face of this Note,
holders must deliver written notice to the Bank at least 30, but no more than
60, days prior to the date of repurchase, but no later than 5:00 p.m. New York


                                       5
<Page>


City time on the last day for giving notice. The written notice must specify the
principal amount to be repurchased and must be signed by a duly authorized
officer of the Depositary participant (signature guaranteed). For definitive
notes, unless otherwise specified on the face of this Note, holders must
complete the "Option to Elect Repayment" on the reverse of this Note and then
deliver this Note to the Bank at least 30, but no more than 45, days prior to
the date of repurchase, but no later than 5:00 p.m. New York City time on the
last day for giving notice. All notices are irrevocable.]* To be modified as
appropriate

               [In the event of redemption or repurchase of this Note in part
only, a new Note or Notes of this series, having the same Stated Maturity,
optional redemption or repurchase provisions, Interest Rate and other terms and
provisions of this Note, in authorized denominations in an aggregate principal
amount equal to the unredeemed portion hereof will be issued in the name of the
holder hereof upon the surrender hereof.]* To be modified as appropriate.

[Remarketing provisions, if any, to be included here]

               [The Notes will not be subject to conversion, amortization or any
sinking fund.]* To be modified as appropriate

               As provided in the Indenture and subject to certain limitations
herein and therein set forth, the transfer of this Note may be registered on the
register of the Notes, upon surrender of this Note for registration of transfer
at the Bank, or at such other agencies as may be designated pursuant to the
Indenture, duly endorsed by, or accompanied by a written instrument of transfer
in form satisfactory to the Trustee or the Bank duly executed by, the holder
hereof or his attorney duly authorized in writing, and thereupon one or more new
Notes, of authorized denominations and for the same aggregate principal amount,
will be issued to the designated transferee or transferees.

               The Notes are issuable only as registered Notes without coupons
in denominations of $1,000 or any amount in excess thereof that is an integral
multiple of $1,000. As provided in the Indenture, and subject to certain
limitations herein and therein set forth, the Notes are exchangeable for a like
aggregate principal amount of Notes of other authorized denominations having the
same interest rate, Stated Maturity, optional redemption or repurchase
provisions, if any, and Original Issue Date, as requested by the Securityholder
surrendering the same.

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

               The Company, the Trustee, the Bank, the Security registrar and
any agent of the Company, the Trustee, the Bank, or the Security registrar may
treat the Securityholder in whose name this Note is registered as the absolute
owner hereof for the


                                       6
<Page>


purpose of receiving payment as herein provided and for all other purposes,
whether or not this Note is overdue, and neither the Company, the Trustee,
the Bank, the Security registrar nor any such agent shall be affected by
notice to the contrary.

               If an Event of Default (as defined in the Indenture) with respect
to the Notes shall occur and be continuing, the principal of all the Notes may
be declared due and payable in the manner and with the effect provided in the
Indenture.

               The Indenture permits, with certain exceptions as therein
provided, the amendment thereof and the modification of the rights and
obligations of the Company and the rights of the holders of the Securities of
any series under the Indenture at any time by the Company with the consent of
the holders of not less than 66 2/3% in aggregate principal amount of the
Securities at the time Outstanding to be affected (voting as one class). The
Indenture also permits the Company and the Trustee to enter into supplemental
indentures without the consent of the holders of Securities of any series for
certain purposes specified in the Indenture, including the making of such other
provisions in regard to matters arising under the Indenture which shall not
adversely affect the interest of the holders of such Securities. The Indenture
also contains provisions permitting the holders of specified percentages in
aggregate principal amount of the Securities of any series at the time
Outstanding, on behalf of the holders of all the Securities of such series, to
waive compliance by the Company with certain provisions of the Indenture and
certain past defaults under the Indenture and their consequences. Any such
consent or waiver by the holder of this Note shall be conclusive and binding
upon such holder and upon all future holders of this Note and of any Note issued
upon the registration of transfer hereof or in exchange herefor or in lieu
hereof whether or not notation of such consent or waiver is made upon this Note.

               The Indenture provides that no holder of any Security of any
series may enforce any remedy with respect to such series under the Indenture
except in the case of refusal or neglect of the Trustee to act after notice of a
continuing Event of Default and after written request by the holders of not less
than 25% in aggregate principal amount of the Outstanding Securities of such
series and the offer to the Trustee of reasonable indemnity; PROVIDED, HOWEVER,
that such provision shall not prevent the holder hereof from enforcing payment
of the principal of or interest on this Note.

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

               No recourse shall be had for the payment of the principal of or
the interest on this Note, or for any claim based hereon, or otherwise in
respect hereof, or based on or in respect of the Indenture or any indenture
supplemental thereto, against any incorporator, stockholder, officer or
director, as such,


                                       7
<Page>


past, present or future, of the Company or any predecessor or successor
corporation, whether by virtue of any constitution, statute or rule of law, or
by the enforcement of any assessment or penalty or otherwise, all such liability
being, by the acceptance hereof and as part of the consideration for the issue
hereof, expressly waived and released.

               This Note shall be governed by and construed in accordance with
the laws of the State of Maryland.


                                 ASSIGNMENT FORM

               To assign this Note, fill in the form below:


Assignee's Social Security or Tax I. D. Number:  ________________


FOR VALUE RECEIVED, the undersigned hereby sells, assigns and transfers unto

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

              (Print or Type Assignee's Name, Address and Zip Code)

the within Note of the Company and hereby does irrevocably constitute and
appoint

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

Attorney to transfer the said Note on the books of the Company, with full power
of substitution in the premises.



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

                              Signature of Assignor
             (Sign exactly as name appears on the face of the Note)


                             Dated: _______________


                                       8
<Page>


                      [HOLDER'S OPTION TO ELECT REPURCHASE]

                    [IN THE CASE OF CERTIFICATED NOTES ONLY]

The undersigned hereby irrevocably requests and instructs the Company to
repurchase the within or attached Note (or portion thereof specified below)
pursuant to its terms at a price equal to ____ % of the principal amount
thereof, together with accrued interest, if any, to the repurchase date, to the
undersigned, at

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
(Print or type name, address and phone number of the undersigned)

For the within or attached Note to be repurchased on the repurchase date, the
Bank must receive at least 30, but not more than 45, days prior to the date of
repurchase, but no later than 5:00 p.m. New York City time on the last day for
giving notice, (i) this Note with the "Option to Elect Repayment" form duly
completed or (ii) a telegram, telex, facsimile transmission or letter from a
member of a national securities exchange or the National Association of
Securities Dealers, Inc. or a commercial bank or a trust company in the United
States of America setting forth the name, address and telephone number of the
holder of such Note, the principal amount of such Note, the amount of the Note
to be repurchased, a statement that the option to elect repayment is being made
thereby and a guarantee that the Note to be repaid with the form entitled
"Option to Elect Repurchase" on the reverse of such Note duly completed will be
received by the Bank not later than five Business Days after the date of such
telegram, telex, facsimile transmission or letter, and such Note and form are
received by the Bank by such fifth Business Day.

If less than the entire principal amount of the within or attached Note is to be
repurchased, specify the portion to be repurchased: $ ______________ and specify
the denomination or denominations of the Note or Notes to be issued to the
holder for the portion of the Note not being repurchased (in the absence of
specific instruction, one such Note will be issued): $ _____________.

NOTICE: The signature to this Option to Elect Repayment must correspond with the
names as written upon the face of the within instrument in every particular,
without alteration or enlargement or any change whatever.



                            -------------------------
                               Signature of Holder
             (Sign exactly as name appears on the face of the Note)


                             Dated: _______________


                                       9