<Page>
================================================================================
Exhibit 4.3
DUQUESNE LIGHT COMPANY
TO
JPMORGAN CHASE BANK
TRUSTEE
----------
SUPPLEMENTAL INDENTURE NO.__
Dated as of __________, 200_
Supplemental to the Indenture of Mortgage
and Deed of Trust dated as of April 1, 1992
----------
Establishing a series of Securities designated
First Mortgage Bonds, Series __
and
Amending certain provisions of said
Indenture of Mortgage and Deed of Trust
================================================================================
<Page>
SUPPLEMENTAL
INDENTURE NO. __ dated as of _____, 200_, between DUQUESNE
LIGHT COMPANY, a corporation duly organized
and existing under the laws of the
Commonwealth of Pennsylvania (hereinafter
sometimes called the "Company"), and
JPMORGAN CHASE BANK, a New York banking
corporation and successor by merger to
The Chase Manhattan Bank, successor in
trust to Mellon Bank, N.A., trustee
(hereinafter sometimes called the
"Trustee"), under the Indenture of Mortgage
and Deed of Trust, dated as of April 1,
1992 (hereinafter called the "Original
Indenture"), this Supplemental Indenture
No. __ being supplemental thereto. The
Original Indenture and any and all
indentures and instruments supplemental
thereto are hereinafter sometimes
collectively called the "Mortgage."
RECITALS OF THE COMPANY
The Original
Indenture was authorized, executed and delivered by the
Company to provide for the issuance from
time to time of its Securities (such
term and all other capitalized terms used
herein without definition having the
meanings assigned to them in the Original
Indenture), to be issued in one or
more series as contemplated therein, and to
provide security for the payment of
the principal of and premium, if any, and
interest, if any, on the Securities.
The Original
Indenture has been recorded in the Recorders' Offices of the
various counties of Pennsylvania as
follows:
In Allegheny
County in Mortgage Book Vol. 12068, page 8;
In Beaver County in
Mortgage Book Vol. 1208, page 520;
In Greene County
in Mortgage Book Vol. 100, page 174;
In Washington
County in Mortgage Book Vol. 1873, page 1;
In Westmoreland
County in Mortgage Book Vol. 2862, page 221;
and has also been recorded in the Office of
the Clerk of County Commission of
Monongahela County, West Virginia, in Deed
of Trust Book Vol. 672, page 129, the
Office of the Clerk of County Commission of
Hancock County, West Virginia, in
Deed of Trust Book Vol. 293, page 46, the
Recorder's Office of Belmont County,
Ohio, in Mortgage Book Vol. 586, page 273,
the Recorder's Office of Columbiana
County, Ohio, in Mortgage Book Vol. 318,
page 289, the Recorder's Office of
Jefferson County, Ohio, in Mortgage Book
Vol. 65, page 675, the Recorder's
Office of Lake County, Ohio, in Mortgage
Book Vol. 711, page 217, and the
Recorder's Office of Monroe County, Ohio,
in Mortgage Book Vol. 129, page 301.
The Company has
heretofore executed and delivered to the Trustee
Supplemental Indentures for the purposes
recited therein and for the purpose of
creating series of Securities as set forth
in Schedule A hereto.
The Company
desires to establish a series of Securities to be designated
"First Mortgage Bonds, Series _", such
series of Securities to be hereinafter
sometimes called "Series No. __."
By virtue of
Section 2 of Article Two of Supplemental Indenture No. 15,
dated as of November 1, 1999, the Holders
of the Securities of Series Nos. 10
through 22 are deemed to have consented to
the amendments to the Original
Indenture set forth therein, the
Outstanding Securities of such series having an
aggregate principal amount of $417,985,000;
by virtue of Article Two of
Supplemental Indenture No. 18, dated as of
April 1, 2002, the Holders of the
<Page>
Securities of Series No. 23 are deemed to
have consented to such amendments to
the Original Indenture, the Outstanding
Securities of such series having an
aggregate principal amount of $200,000,000;
by virtue of Article Two of
Supplemental Indenture No. 19, dated as of
April 15, 2002, the Holders of the
Securities of Series No. 24 are deemed to
have consented to such amendments to
the Original Indenture, the Outstanding
Securities of such series having an
aggregate principal amount of $100,000,000;
at the date of the execution and
delivery of this Supplemental Indenture No.
20, the aggregate principal amount
of Securities of all series Outstanding
under the Indenture is $757,985,000; and
the aggregate principal amount of the
Securities of Series Nos. 10 through 24 is
$717,985,000, which is more than a majority
in principal amount of all
Securities Outstanding. Accordingly, the
Company now desires to effect the
amendments to the Original Indenture set
forth in Section 2 of Article Two of
Supplemental Indenture No. 15 in accordance
with Sections 1402 and 1403 of the
Original Indenture.
The Company has
duly authorized the execution and delivery of this
Supplemental Indenture No. __ to establish
the Securities of Series No. __ and
has duly authorized the issuance of such
Securities and to make the amendments
to the Original Indenture referred to
above; and all acts necessary to make this
Supplemental Indenture No. __ a valid
agreement of the Company, and to make the
Securities of Series No. __ valid
obligations of the Company, have been
performed.
NOW, THEREFORE,
THIS SUPPLEMENTAL INDENTURE NO. __ WITNESSETH, that, in
consideration of the premises and of the
purchase of the Securities by the
Holders thereof, and in order to secure the
payment of the principal of and
premium, if any, and interest, if any, on
all Securities from time to time
Outstanding and the performance of the
covenants contained therein and in the
Mortgage and to declare the terms and
conditions on which such Securities are
secured, the Company hereby grants,
bargains, sells, releases, conveys, assigns,
transfers, mortgages, pledges, sets over
and confirms to the Trustee, and grants
to the Trustee a security interest in, the
following:
GRANTING CLAUSE FIRST
All right, title and interest of the Company in and to property
(other
than Excepted
Property), real, personal and mixed and wherever situated, in
any case used or
to be used in or in connection with the generation,
purchase,
transmission, distribution or sale by the Company of electric
energy (whether
or not such use is the sole use of such property),
including,
without limitation, (a) all lands, easements, servitudes,
licenses,
permits, rights of way and other rights and interests in or
relating to real
property or the occupancy or use of the same; (b) all
plants,
generators, turbines, engines, boilers, fuel handling and
transportation
facilities, air and water pollution control and sewage and
solid waste
disposal facilities and other machinery and facilities for the
generation of
electric energy; (c) all switchyards, lines, towers,
substations,
transformers and other machinery and facilities for the
transmission of
electric energy; (d) all lines, poles, conduits,
conductors,
meters, regulators and other machinery and facilities for the
distribution of
electric energy; (e) all buildings, offices, warehouses and
other
structures; and (f) all pipes, cables, insulators, ducts,
tools,
computers and
other data processing and/or storage equipment and other
equipment,
apparatus and
2
<Page>
facilities and
all other property, of whatever kind and nature, ancillary
to or otherwise
used or to be used in conjunction with any or all of the
foregoing or
otherwise, directly or indirectly, in furtherance of the
generation,
purchase, transmission, distribution or sale by the Company of
electric
energy;
GRANTING CLAUSE SECOND
Subject to the applicable exceptions permitted by Section 810,
Section
1303 and Section
1305 of the Original Indenture, all property (other than
Excepted
Property) of the kind and nature described in Granting Clause
First which may
be hereafter acquired by the Company, it being the
intention of the
Company that all such property acquired by the Company
after the date
of the execution and delivery of this Supplemental Indenture
No. __ shall be
as fully embraced within and subjected to the Lien hereof
as if such
property were owned by the Company as of the date of the
execution and
delivery of this Supplemental Indenture No. __;
GRANTING CLAUSE FOURTH
All other property of whatever kind and nature subjected or
intended
to be subjected
to the Lien of the Mortgage by any of the terms and
provisions
thereof;
EXCEPTED
PROPERTY
Expressly excepting and excluding, however, from the Lien and
operation of the
Mortgage all Excepted Property of the Company, whether now
owned or
hereafter acquired;
TO HAVE AND TO
HOLD all such property, real, personal and mixed, unto the
Trustee forever;
SUBJECT,
HOWEVER, to Permitted Liens and to Liens which have been
granted
by the Company to other Persons prior to
the date of the execution and delivery
of the Original Indenture and subject also,
as to any property acquired by the
Company after the date of execution and
delivery of the Original Indenture, to
vendors' Liens, purchase money mortgages
and other Liens thereon at the time of
the acquisition thereof (including, but not
limited to, the Lien of any Class
"A" Mortgage), it being understood that
with respect to any of such property
which was at the date of execution and
delivery of the Original Indenture or
thereafter became or hereafter becomes
subject to the Lien of any Class "A"
Mortgage, the Lien of the Mortgage shall at
all times be junior and subordinate
to the Lien of such Class "A" Mortgage;
IN TRUST,
NEVERTHELESS, for the equal and proportionate benefit and
security of the Holders from time to time
of all Outstanding Securities without
any priority of any such Security over any
other such Security;
PROVIDED,
HOWEVER, that if, after the right, title and interest of the
Trustee in and to the Mortgaged Property
shall have ceased, terminated and
become void in accordance with Article Nine
of the Original Indenture, the
principal of and premium, if any, and
interest, if any,
3
<Page>
on the Securities shall have been paid to
the Holders thereof, or shall have
been paid to the Company pursuant to
Section 603 of the Original Indenture, then
and in that case the Mortgage and the
estate and rights thereby granted shall
cease, terminate and be void, and the
Trustee shall cancel and discharge the
Mortgage and execute and deliver to the
Company such instruments as the Company
shall require to evidence the discharge
thereof; otherwise the Mortgage shall be
and remain in full force and effect;
and
THE PARTIES HEREBY FURTHER COVENANT AND AGREE as follows:
ARTICLE ONE
TWENTY-_____ SERIES OF SECURITIES
There is hereby
created a series of Securities designated "First Mortgage
Bonds, Series _", which series shall
constitute Series No. __. The form and
terms of the Securities of Series No. __
shall be established in or pursuant to
an Officer's Certificate. The Securities of
Series No. __ shall be initially
authenticated and delivered in the
aggregate principal amount of $_________, but
shall not be limited in aggregate principal
amount.
ARTICLE TWO
AMENDMENTS
The Original
Indenture is hereby amended as set forth in Schedule B hereto.
ARTICLE THREE
MISCELLANEOUS PROVISIONS
This
Supplemental Indenture No. __ is a supplement to the Mortgage.
As
supplemented by this Supplemental Indenture
No. __, the Mortgage is in all
respects ratified, approved and confirmed,
and the Mortgage and this
Supplemental Indenture No. __ shall
together constitute one and the same
instrument.
4
<Page>
IN WITNESS
WHEREOF, the parties hereto have caused this Supplemental
Indenture No. __ to be duly executed, and
their respective corporate seals to be
hereunto affixed and attested, all as of
the day and year first above written.
DUQUESNE LIGHT COMPANY
By:
-----------------------------------
VICE PRESIDENT AND TREASURER
Attest:
-----------------------------
SECRETARY
JPMORGAN CHASE BANK, Trustee
By:
-----------------------------------
VICE PRESIDENT
Attest:
------------------------------
AUTHORIZED OFFICER
5
<Page>
COMMONWEALTH OF PENNSYLVANIA )
)ss.:
COUNTY OF ALLEGHENY
)
On the day of
_____, 200_, before me personally came William F. Fields, to
me known, who, being by me duly sworn, did
depose and say that he is a Vice
President and the Treasurer of Duquesne
Light Company, the corporation described
in and which executed the foregoing
instrument; that he knows the seal of said
corporation; that the seal affixed to said
instrument is such corporate seal;
that it was so affixed by authority of the
Board of Directors of said
corporation, and that he signed his name
thereto by like authority.
---------------------------
Notary Public
COMMONWEALTH OF PENNSYLVANIA )
) ss.:
COUNTY OF ALLEGHENY
)
On the day of _____, 200_, before me personally came Kent M.
Christman,
to me known, who, being by me duly sworn,
did depose and say that he is a Vice
President of JPMorgan Chase Bank, the
banking corporation described in and which
executed the foregoing instrument; that he
knows the seal of said banking
corporation; that the seal affixed to said
instrument is the s
