Exhibit
4.(a)(3)


Form of
Supplemental Indenture

(First Mortgage Bonds)


PUBLIC SERVICE
COMPANY

OF COLORADO


TO


U.S. BANK TRUST
NATIONAL ASSOCIATION,


AS TRUSTEE


SUPPLEMENTAL
INDENTURE NO.      


Dated as of                       


Supplemental to
the Indenture

dated as of October 1, 1993


Establishing the
Securities of Series No.           

designated First Mortgage Bonds, Series No.             











SUPPLEMENTAL INDENTURE NO.     ,
dated as of                     ,
between PUBLIC SERVICE COMPANY OF COLORADO, a corporation duly organized and
existing under the laws of the State of Colorado (hereinafter sometimes called
the “Company”), and U.S. BANK TRUST NATIONAL ASSOCIATION (FORMERLY FIRST TRUST
OF NEW YORK, NATIONAL ASSOCIATION), a national banking association, as successor
trustee (hereinafter sometimes called the “Trustee”) to Morgan Guaranty Trust
Company of New York under the Indenture, dated as of October 1, 1993
(hereinafter called the “Original Indenture”), as previously supplemented and
as further supplemented by this Supplemental Indenture No.     .
The Original Indenture and any and all indentures and all other instruments
supplemental thereto are hereinafter sometimes collectively called the “Indenture”.


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 Company has heretofore executed and delivered to
the Trustee the Supplemental Indentures referred to in Schedule A hereto for
the purpose of establishing a series of bonds and appointing the successor
Trustee.


The Company desires to establish a new series of
Securities to be designated “First Mortgage Bonds, Series No.     ,”
such series of Securities to be hereinafter sometimes called “Series No.     .”


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 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.


GRANTING CLAUSES


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 Indenture 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, as of
the date of the execution and delivery of this Supplemental Indenture No.     ,
in and to 



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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 Electric Utility Business
(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 used or to
be used in or in connection with the Electric Utility Business or relating to
the occupancy or use of such real property, subject however, to the exceptions
and exclusions set forth in clause (a) of Granting Clause First of the Original
Indenture; (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
used or to be used in or in connection with the Electric Utility Business; (f)
all pipes, cables, insulators, ducts, tools, computers and other data
processing and/or storage equipment and other equipment, apparatus and facilities
used or to be used in or in connection with the Electric Utility Business; (g)
any or all of the foregoing properties in the process of construction; and (h)
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 Electric Utility Business;


GRANTING CLAUSE SECOND


Subject to the applicable exceptions permitted by
Section 810(c), 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 required to be subjected to the Lien of the Indenture by any of
the provisions thereof;



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EXCEPTED PROPERTY


Expressly excepting and excluding, however, from the
Lien and operation of the Indenture 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, its successors in trust and their assigns forever;


SUBJECT, HOWEVER, to (a) Liens existing at the date of
the execution and delivery of the Original Indenture, (b) as to property
acquired by the Company after the date of the execution and delivery of the
Original Indenture, Liens existing or placed thereon at the time of the
acquisition thereof (including, but not limited to, the Lien of any Class A
Mortgage and purchase money Liens), (c) Retained Interests and (d) any other
Permitted Liens, it being understood that, with respect to any 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 Indenture shall at all times be junior, subject 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 the right, title and interest
of the Trustee in and to the Mortgaged Property shall cease, terminate and
become void in accordance with, and subject to the conditions set forth in,
Article Nine of the Original Indenture, and if, thereafter, the principal of
and premium, if any, and interest, if any, 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 Indenture
shall terminate, and the Trustee shall execute and deliver to the Company such
instruments as the Company shall require to evidence such termination;
otherwise the Indenture, and the estate and rights thereby granted shall be and
remain in full force and effect; and


THE PARTIES HEREBY FURTHER COVENANT AND AGREE as
follows:


Article One



SECURITIES OF SERIES NO.     


There are hereby established the Securities of Series
No.     , which shall have the terms and characteristics
set forth below (the lettered subdivisions set forth below corresponding to the
lettered subdivisions of Section 301 of the Original Indenture):


(a)           the title of the Securities of Series No.     
shall be “First Mortgage Bonds, Series No.     ”;


(b)           the Securities of Series No.     
shall be initially authenticated and delivered in the aggregate principal
amount of $                      ;



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(c)           interest on the Securities of Series No.     
shall be payable to the Persons in whose names such Securities are registered
at the close of business on the Regular Record Date for such interest, except
as otherwise expressly provided in the form of such Securities attached as
Exhibit A hereto;


(d)           the principal of the Securities of Series No.     
shall be payable on                     ,
the Stated Maturity for Series No.     ;


(e)           the Securities of Series No.     
shall bear interest at a rate of           %
per annum; interest shall accrue on the Securities of Series No.     
from                       ,
or the most recent date to which interest has been paid or duly provided for;
the Interest Payment Dates for such Securities shall be                 
and               
in each year, commencing                   ,
and the Regular Record Dates with respect to the Interest Payment Dates for
such Securities shall be               
and               
in each year, respectively (whether or not a Business Day);


(f)            the Corporate Trust Office of U.S. Bank Trust National
Association in New York, New York shall be the place at which (i) the principal
of, premium, if any, and interest, if any, on the Securities of Series No.     
shall be payable, (ii) registration of transfer of such Securities may be
effected, (iii) exchanges of such Securities may be effected and (iv) notices
and demands to or upon the Company in respect of such Securities and the
Indenture may be served; and U.S. Bank Trust National Association shall be the
Security Registrar for such Securities; provided, however, that the Company
reserves the right to change, by one or more Officer’s Certificates, any such
place or the Security Registrar; and provided, further, that the Company
reserves the right to designate, by one or more Officer’s Certificates, its
principal office in Denver, Colorado as any such place or itself as the
Security Registrar;


(g)           the Securities of Series No.     
[shall not be redeemable prior to maturity] [shall be redeemable] at the option
of the Company on and after                       
in whole or part at a redemption price of             .


(h)           not applicable;


(i)            not applicable;


(j)            not applicable;


(k)           not applicable;


(l)            not applicable;


(m)          not applicable;


(n)           not applicable;


(o)           not applicable;


(p)           not applicable;



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(q)           the Securities of Series No.      are
to be initially registered in the name of Cede & Co., as nominee for The
Depository Trust Company (the “Depositary”). 
Such Securities shall not be transferable or exchangeable, nor shall any
purported transfer be registered, except as follows:


(i)            such Securities may be transferred in whole, and
appropriate registration of transfer effected, if such transfer is by such
nominee to the Depositary, or by the Depositary to another nominee thereof, or
by any nominee of the Depositary to any other nominee thereof, or by the
Depositary or any nominee thereof to any successor securities depositary or any
nominee thereof; and


(ii)           such Securities may be exchanged for definitive Securities
registered in the respective names of the beneficial holders thereof, and
thereafter shall be transferable without restriction, if:


(A)          the Depositary, or any successor securities depositary,
shall have notified the Company and the Trustee that it is unwilling or unable
to continue to act as securities depositary with respect to such Securities or
the Depositary has ceased to be a clearing agency registered under the
Securities Exchange Act of 1934, as amended, and the Trustee shall not have
been notified by the Company within ninety (90) days of the identity of a
successor securities depositary with respect to such Securities; or


(B)           the Company shall have delivered to the Trustee a Company
Order to the effect that such Securities shall be so exchangeable on and after
a date specified therein;


(r)            not applicable;


(s)           no service charge shall be made for the registration of
transfer or exchange of the Securities of Series No.     ;
provided, however, that the Company may require payment of a sum sufficient to
cover any tax or other governmental charge payable in connection with the
exchange or transfer;


(t)            not applicable;


(u)           (i)            If the
Company shall have caused the Company’s indebtedness in respect of any
Securities of Series No.      to have been satisfied and
discharged prior to the Maturity of such Securities, as provided in Section 901
of the Original Indenture, the Company shall, promptly after the date of such
satisfaction and discharge, give a notice to each Person who was a Holder of
any of such Securities on such date stating (A)(1) the aggregate principal
amount of such Securities and (2) the aggregate amount of any money (other than
amounts, if any, deposited in respect of accrued interest on such Securities)
and the aggregate principal amount of, the rate or rates of interest on, and
the aggregate fair market value of, any Eligible Obligations deposited pursuant
to Section 901 of the Original Indenture with respect to such Securities and
(B) that the Company will provide (and the Company shall promptly so provide)
to such Person, or any beneficial owner of such Securities holding through such
Person (upon written request to the Company sent to an address specified in
such notice), such other information as such Person or beneficial owner, as the
case may be, reasonably may request in order to enable it to determine the
federal income tax consequences to it resulting from the 



 6
 








satisfaction and discharge of the Company’s
indebtedness in respect of such Securities. 
Thereafter, the Company shall, within forty-five (45) days after the end
of each calendar year, give to each Person who at any time during such calendar
year was a Holder of such Securities a notice containing (X) such information
as may be necessary to enable such Person to report its income, gain or loss
for federal income tax purposes with respect to such Securities or the assets
held on deposit in respect thereof during such calendar year or the portion
thereof during which such Person was a Holder of such Securities, as the case
may be (such information to be set forth for such calendar year as a whole and
for each month during such year) and (Y) a statement to the effect that the
Company will provide (and the Company shall promptly so provide) to such
Person, or any beneficial owner of such Securities holding through such Person
(upon written request to the Company sent to an address specified in such
notice), such other information as such Person or beneficial owner, as the case
may be, reasonably may request in order to enable it to determine its income,
gain or loss for federal income tax purposes with respect to such Securities or
such assets for such year or portion thereof, as the case may be.  The obligation of the Company to provide or
cause to be provided information for purposes of income tax reporting by any
Person as described in the first two sentences of this paragraph shall be
deemed to have been satisfied to the extent that the Company has provided or
caused to be provided substantially comparable information pursuant to any
requirements of the Internal Revenue Code of 1986, as amended from time to time
(the “Code”) and United States Treasury regulations thereunder.


(ii)           Notwithstanding the provisions of subparagraph (i) above,
the Company shall not be required to give any notice specified in such
subparagraph or to otherwise furnish any of the information contemplated
therein if the Company shall have delivered to the Trustee an Opinion of
Counsel to the effect that the Holders of such Securities will not recognize
income, gain or loss for federal income tax purposes as a result of the
satisfaction and discharge of the Company’s indebtedness in respect of such
Securities and such Holders will be subject to federal income taxation on the
same amounts and in the same manner and at the same times as if such
satisfaction and discharge had not occurred.


(iii)          Anything in this clause (u) to the contrary
notwithstanding, the Company shall not be required to give any notice specified
in subparagraph (i) or to otherwise furnish the information contemplated
therein or to deliver any Opinion of Counsel contemplated by subparagraph (ii)
if the Company shall have caused Securities of Series No.     
to be deemed to have been paid for purposes of the Indenture, as provided in
Section 901 of the Original Indenture, but shall not have effected the
satisfaction and discharge of its indebtedness in respect of such Securities
pursuant to such Section.


(iv)          The Securities of Series No.      shall
be substantially in the form attached hereto as Exhibit A and shall have such
further terms as are set forth in such form.


Article Two



MISCELLANEOUS PROVISIONS


This Supplemental Indenture No.     
is a supplement to the Original Indenture. 
As previously supplemented and further supplemented by this Supplemental
Indenture No.     , the 



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Original Indenture is in all respects ratified,
approved and confirmed, and the Original Indenture, all previous supplements thereto
and this Supplemental Indenture No.      shall together
constitute one and the same instrument.


IN WITNESS WHEREOF, the parties hereto have caused
this Supplemental Indenture No.      to be duly executed as
of the day and year first above written.


	
  

  	
  PUBLIC SERVICE COMPANY OF COLORADO 

  
	
   

  	
   

  
	
   

  	
  By:

  	
   

  	
   

  
	
   

  	
   

  	
  Name:

  
	
   

  	
   

  	
  Title: Vice President and

  	
   

  	
   

  
	
   

  	
   

  
	
   

  	
   

  
	
  STATE OF 

  	
  )

  
	
   

  	
  )  ss.:

  
	
  CITY OF

  	
  )

  
						



 


On the        day of                       ,
before me personally came to me known, who, being by me duly sworn, did depose
and say that he is a Vice President and                 
of Public Service Company of Colorado, one of the corporations described in and
which executed the foregoing instrument; and that he signed his name thereto by
authority of the Board of Directors of said corporation.


	
   

  	
   

  	
   

  
	
  

  	
  Name:

  
	
   

  	
  Notary Public, State of

  
	
   

  	
   

  
	
   

  	
  Commission Expires:

  



 



 8
 








 


	
  

  	
  U.S. BANK TRUST NATIONAL
  ASSOCIATION

  
	
   

  	
   

  
	
   

  	
   

  	
  By:

  	
   

  
	
   

  	
  Name:

  
	
   

  	
  Title: Assistant
  Vice President

  
	
   

  	
   

  
	
   

  	
   

  
	
  STATE OF NEW
  YORK

  	
  )

  
	
   

  	
  )  ss.:

  
	
  CITY AND COUNTY
  OF NEW YORK

  	
  )

  
	
   

  	
   

  
					



 


On the        day of                         ,
before me personally came                           ,
to me known, who, being by me duly sworn, did depose and say that he is an
Assistant Vice President of U.S. Bank Trust National Association, the banking
association described in and which executed the foregoing instrument; and that
he signed his name thereto by authority of the Board of Directors of said
banking association.


 


	
  

  	
   

  	
   

  
	
  

  	
  Name: 

  
	
   

  	
  Notary Public, State of New York 

  
	
   

  	
   

  
	
   

  	
  Commission Expires:

  



 



 9














EXHIBIT A


FORM OF SECURITY



(See legend at the end of this Security for

restrictions on transfer)


PUBLIC SERVICE
COMPANY OF COLORADO

First Mortgage Bond, Series No.    


	
  Original Interest Accrual
  Date:

  	
   

  	
   

  	
   

  
	
  Interest Rate:

  	
   

  	
             %

  	
   

  
	
  Stated Maturity:

  	
   

  	
   

  	
   

  
	
  Interest Payment
  Dates:

  	
   

  	
   

  	
  and

  
	
  Regular Record
  Dates:

  	
   

  	
   

  	
  and

  



 


This Security is not a Discount Security 


within the meaning of the within mentioned Indenture


	
  Principal Amount 

  	
         Registered
  No.

  
	
  $

  	
  CUSIP

  



 


PUBLIC SERVICE COMPANY OF COLORADO, a corporation duly
organized and existing under the laws of the State of Colorado (herein called
the “Company,” which term includes any successor corporation under the
Indenture referred to below), for value received, hereby promises to pay to, or
registered assigns, the principal sum of                                     
Dollars on the Stated Maturity specified above, and to pay interest thereon
from the Original Interest Accrual Date specified above or from the most recent
Interest Payment Date to which interest has been paid or duly provided for,
semi-annually in arrears on the Interest Payment Dates specified above in each
year, commencing                       ,
and at Maturity, at the Interest Rate per annum specified above, until the
principal hereof is paid or duly provided for. 
The interest so payable, and paid or duly provided for, on any Interest
Payment Date shall, as provided in such Indenture, be paid to the Person in
whose name this Security (or one or more Predecessor Securities) is registered
at the close of business on the Regular Record Date specified above (whether or
not a Business Day) next preceding such Interest Payment Date.  Notwithstanding the foregoing, interest
payable at Maturity shall be paid to the Person to whom principal shall be
paid.  Except as otherwise provided in
said Indenture, any such interest not so paid or duly provided for shall
forthwith cease to be payable to the Holder on such Regular Record Date and may
either be paid to the Person in whose name this Security (or one or more
Predecessor Securities) is registered at the close of business on a Special
Record Date for the payment of such Defaulted Interest to be fixed by the
Trustee, notice of which shall be given to Holders of Securities of this series
not less than 15 days prior to such Special Record Date, or be paid in such
other manner as permitted by the Indenture.


Payment of the principal of this Security and interest
hereon at Maturity shall be made upon presentation of this Security at the
Corporate Trust Office of U.S. Bank Trust National 



 A-1
 








Association, in New York, New York or at such other
office or agency as may be designated for such purpose by the Company from time
to time.  Payment of interest on this
Security (other than interest at Maturity) shall be made by check mailed to the
address of the Person entitled thereto as such address shall appear in the
Security Register, except that if such Person shall be a securities depositary,
such payment may be made by such other means in lieu of check as shall be
agreed upon by the Company, the Trustee and such Person.  Payment of the principal of and interest on
this Security, as aforesaid, shall be made in such coin or currency of the
United States of America as at the time of payment shall be legal tender for
the payment of public and private debts.


This Security is one of a duly authorized issue of
securities of the Company (herein called the “Securities”), issued and issuable
in one or more series under and equally secured by an Indenture, dated as of
October 1, 1993 (such Indenture as originally executed and delivered and as
supplemented or amended from time to time thereafter, together with any
constituent instruments establishing the terms of particular Securities, being
herein called the “Indenture”), between the Company and U.S. Bank Trust
National Association (formerly First Trust of New York, National Association)
as successor trustee (herein called the “Trustee,” which term includes any
successor trustee under the Indenture), to which Indenture and all indentures
supplemental thereto reference is hereby made for a description of the property
mortgaged, pledged and held in trust, the nature and extent of the security and
the respective rights, limitations of rights, duties and immunities of the
Company, the Trustee and the Holders of the Securities thereunder and of the
terms and conditions upon which the Securities are, and are to be,
authenticated and delivered and secured. 
The acceptance of this Security shall be deemed to constitute the
consent and agreement by the Holder hereof to all of the terms and provisions
of the Indenture.  This Security is one
of the series designated above.


If any Interest Payment Date or the Stated Maturity
shall not be a Business Day (as hereinafter defined), payment of the amounts
due on this Security on such date may be made on the next succeeding Business
Day; and, if such payment is made or duly provided for on such Business Day, no
interest shall accrue on such amounts for the period from and after such
Interest Payment Date or Stated Maturity, as the case may be, to such Business
Day.


This Security [shall not be redeemable] [shall be
redeemable at the option of the Company on and after                       
in whole or in part, at a redemption price equal to                           ].



If an Event of Default shall occur and be continuing,
the principal of this Security 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 Trustee to enter into one or more supplemental indentures
for the purpose of adding any provisions to, or changing in any manner or
eliminating any of the provisions of, the Indenture with the consent of the
Holders of not less than a majority in aggregate principal amount of the
Securities of all series then Outstanding under the Indenture, considered as
one class; provided, however, that if there shall be Securities of more than
one series Outstanding under the Indenture and if a proposed supplemental
indenture shall directly affect the rights of the Holders of Securities of one
or more, but less than all, of such series, then the consent only of the
Holders of a majority in 



 A-2
 








aggregate principal amount of the Outstanding
Securities of all series so directly affected, considered as one class, shall
be required; and provided, further, that if the Securities of any series shall
have been issued in more than one Tranche and if the proposed supplemental indenture
shall directly affect the rights of the Holders of Securities of one or more,
but less than all, of such Tranches, then the consent only of the Holders of a
majority in aggregate principal amount of the Outstanding Securities of all
Tranches so directly affected, considered as one class, shall be required; and
provided, further, that the Indenture permits the Trustee to enter into one or
more supplemental indentures for limited purposes without the consent of any
Holders of Securities.  The Indenture also
contains provisions permitting the Holders of a majority in principal amount of
the Securities then Outstanding, on behalf of the Holders of all Securities, to
waive compliance by the Company with certain provisions of the Indenture and
certain past defaults under the Indenture and their consequences.  Any such consent or waiver by the Holder of
this Security shall be conclusive and binding upon such Holder and upon all
future Holders of this Security and of any Security issued upon the
registration of transfer hereof or in exchange therefor or in lieu hereof,
whether or not notation of such consent or waiver is made upon this Security.


As provided in the Indenture and subject to certain
limitations therein set forth, this Security or any portion of the principal
amount hereof will be deemed to have been paid for all purposes of the
Indenture and to be no longer Outstanding thereunder, and, at the election of
the Company, the Company’s entire indebtedness in respect thereof will be
satisfied and discharged, if there has been irrevocably deposited with the
Trustee or any Paying Agent (other than the Company), in trust, money in an
amount which will be sufficient and/or Eligible Obligations, the principal of
and interest on which when due, without regard to any reinvestment thereof,
will provide moneys which, together with moneys so deposited, will be
sufficient, to pay when due the principal of and interest on this Security when
due.


As provided in the Indenture and subject to certain
limitations therein set forth, the transfer of this Security is registrable in
the Security Register, upon surrender of this Security for registration of
transfer at the office of U.S. Bank Trust National Association, in New York,
New York or such other office or agency as may be designated by the Company
from time to time, duly endorsed by, or accompanied by a written instrument of
transfer in form satisfactory to the Company and the Security Registrar duly
executed by, the Holder hereof or his attorney duly authorized in writing, and
thereupon one or more new Securities of this series of authorized denominations
and of like tenor and aggregate principal amount, will be issued to the
designated transferee or transferees.


The Securities of this series are issuable only as
registered Securities, without coupons, and in denominations of $1,000 and
integral multiples thereof.  As provided
in the Indenture and subject to certain limitations therein set forth,
Securities of this series are exchangeable for a like aggregate principal amount
of Securities of the same series, of any authorized denominations, as requested
by the Holder surrendering the same, and of like tenor upon surrender of the
Security or Securities to be exchanged at the office of U.S. Bank Trust
National Association, in New York, New York or such other office or agency as
may be designated by the Company from time to time.



 A-3
 








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


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


The Indenture and the Securities shall be governed by
and construed in accordance with the laws of the State of New York.


As used herein “Business Day” means any day, other
than a Saturday or Sunday, which is not a day on which banking institutions or
trust companies in The City of New York, New York or other city in which is
located any office or agency maintained for the payment of principal or
interest on this Security, are authorized or required by law, regulation or
executive order to remain closed.  All
other terms used in this Security which are defined in the Indenture shall have
the meanings assigned to them in the Indenture.


As provided in the Indenture, no recourse shall be had
for the payment of the principal of or interest on any Securities, or any part
thereof, or for any claim based thereon or otherwise in respect thereof, or of
the indebtedness represented thereby, or upon any obligation, covenant or
agreement under the Indenture, against, and no personal liability whatsoever
shall attach to, or be incurred by, any incorporator, shareholder, officer or
director, as such, past, present or future of the Company or of any predecessor
or successor corporation (either directly or through the Company or a
predecessor or successor corporation), whether by virtue of any constitutional
provision, statute or rule of law, or by the enforcement of any assessment or
penalty or otherwise; it being expressly agreed and understood that the
Indenture and all the Securities are solely corporate obligations and that any
such personal liability is hereby expressly waived and released as a condition
of, and as part of the consideration for, the execution of the Indenture and
the issuance of the Securities.


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



 A-4














IN WITNESS WHEREOF, the Company has caused this
instrument to be duly executed and its corporate seal to be hereunto affixed
and attested.


	
  

  	
  PUBLIC SERVICE COMPANY OF COLORADO 

  
	
   

  	
   

  
	
   

  	
  By:

  	
   

  	
   

  
	
   

  	
   

  	
        [Title]

  
	
   

  	
   

  
	
   

  	
   

  
	
  Attest:

  	
   

  	
   

  	
   

  
	
   

  	
  [Title]

  	
   

  
						



 


CERTIFICATE OF
AUTHENTICATION


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


	
  Dated:

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
  U.S. BANK TRUST 

  NATIONAL ASSOCIATION, as Trustee

  	
  OR

  	
  U.S. BANK TRUST 

  NATIONAL ASSOCIATION, as Trustee

  
	
   

  	
   

  	
   

  
	
  By:

  	
   

  	
   

  	
   

  	
  By:

  	
   

  
	
   

  	
  Authorized
  Officer

  	
   

  	
   

  	
  AS AUTHENTICATION AGENT 

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By:

  	
   

  
	
   

  	
   

  	
     Authorized
  Officer

  
							



 


UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION (“DTC”),
TO THE COMPANY OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT,
AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN
SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY
PAYMENT IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN
AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF
FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE
REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.


THIS SECURITY MAY NOT BE TRANSFERRED OR EXCHANGED, NOR
MAY ANY PURPORTED TRANSFER BE REGISTERED, EXCEPT (i) THIS SECURITY MAY BE
TRANSFERRED IN WHOLE, AND APPROPRIATE REGISTRATION OF TRANSFER EFFECTED, IF
SUCH TRANSFER IS BY CEDE & CO., AS NOMINEE FOR THE DEPOSITORY TRUST COMPANY
(THE “DEPOSITARY”), TO THE DEPOSITARY, OR BY THE DEPOSITARY TO ANOTHER NOMINEE
THEREOF, OR BY ANY NOMINEE OF THE DEPOSITARY TO ANY OTHER NOMINEE THEREOF, OR
BY THE DEPOSITARY OR ANY NOMINEE THEREOF TO ANY SUCCESSOR SECURITIES DEPOSITARY
OR 











ANY NOMINEE THEREOF; AND (ii) THIS SECURITY MAY BE
EXCHANGED FOR DEFINITIVE SECURITIES REGISTERED IN THE RESPECTIVE NAMES OF THE
BENEFICIAL HOLDERS HEREOF, AND THEREAFTER SHALL BE TRANSFERABLE WITHOUT
RESTRICTIONS IF: (A) THE DEPOSITARY, OR ANY SUCCESSOR SECURITIES DEPOSITARY,
SHALL HAVE NOTIFIED THE COMPANY AND THE TRUSTEE THAT IT IS UNWILLING OR UNABLE
TO CONTINUE TO ACT AS SECURITIES DEPOSITARY WITH RESPECT TO THE SECURITIES AND
THE TRUSTEE SHALL NOT HAVE BEEN NOTIFIED BY THE COMPANY WITHIN NINETY (90) DAYS
OF THE IDENTITY OF A SUCCESSOR SECURITIES DEPOSITARY WITH RESPECT TO THE
SECURITIES; OR (B) THE COMPANY SHALL HAVE DELIVERED TO THE TRUSTEE A COMPANY
ORDER TO THE EFFECT THAT THE SECURITIES SHALL BE SO EXCHANGEABLE ON AND AFTER A
DATE SPECIFIED THEREIN.


FOR VALUE RECEIVED THE
UNDERSIGNED HEREBY SELLS, assigns and transfers unto


 


[please insert
social security or other identifying number of assignee]


 


[please print or
typewrite name and address of assignee]


 


the within Security of PUBLIC SERVICE COMPANY OF
COLORADO and does hereby irrevocably constitute and appoint                                         
Attorney, to transfer said Security on the books of the within-mentioned
Company, with full power of substitution in the premises.


	
  Dated:

  	
   

  	
   

  	
   

  



 


Notice:  The
signature to this assignment must correspond with the name as written upon the
face of the Security in every particular without alteration or enlargement or
any change whatsoever.











SCHEDULE A


SUPPLEMENTAL INDENTURES


	
  Date of

  Supplemental

  Indenture

  	
   

  	
  Series of Bonds

  	
   

  	
  Principal

  Amount Issued

  	
   

  	
  Principal

  Amount

  Outstanding

  	
   

  
	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  
	
  November 1, 1993

  	
   

  	
  Series
  No. 1

  	
   

  	
  $

  	
  134,500,000

  	
   

  	
  None

  	
   

  
	
  January 1, 1994

  	
   

  	
  Series
  No. 2 due 2001

  	
   

  	
  $

  	
  102,667,000

  	
   

  	
  None

  	
   

  
	
   

  	
   

  	
  and

  Series No. 2 due 2024

  	
   

  	
  $

  	
  110,000,000

  	
   

  	
  None

  	
   

  
	
  September 2, 1994
  (Appointment of Successor Trustee)

  	
   

  	
  None

  	
   

  	
  None

  	
   

  	
  None

  	
   

  
	
  May 1, 1996

  	
   

  	
  Series
  No. 3

  	
   

  	
  $

  	
  125,000,000

  	
   

  	
  None

  	
   

  
	
  November 1, 1996

  	
   

  	
  Series
  No. 4

  	
   

  	
  $

  	
  250,000,000

  	
   

  	
  $

  	
  100,000,000

  	
   

  
	
  February 1, 1997

  	
   

  	
  Series
  No. 5

  	
   

  	
  $

  	
  150,000,000

  	
   

  	
  None

  	
   

  
	
  April 1, 1998

  	
   

  	
  Series
  No. 6

  	
   

  	
  $

  	
  250,000,000

  	
   

  	
  None

  	
   

  
	
  August 15, 2002

  	
   

  	
  Series
  No. 7

  	
   

  	
  $

  	
  48,750,000

  	
   

  	
  $

  	
  48,750,000

  	
   

  
	
  September 1, 2002

  	
   

  	
  Series
  No. 8

  	
   

  	
  $

  	
  600,000,000

  	
   

  	
  None

  	
   

  
	
  September 15,
  2002

  	
   

  	
  Series
  No. 9

  	
   

  	
  $

  	
  530,000,000

  	
   

  	
  None

  	
   

  
	
  April 1, 2003

  	
   

  	
  Series
  No. 10

  	
   

  	
  $

  	
  600,000,000

  	
   

  	
  $

  	
  600,000,000

  	
   

  
	
  March 1, 2003

  	
   

  	
  Series
  No. 11

  	
   

  	
  $

  	
  250,000,000

  	
   

  	
  None

  	
   

  
	
  September 15, 2003

  	
   

  	
  Series
  No. 12

  	
   

  	
  $

  	
  250,000,000

  	
   

  	
  $

  	
  250,000,000

  	
   

  
	
  May 1, 2003

  	
   

  	
  Series
  No. 13

  	
   

  	
  $

  	
  350,000,000

  	
   

  	
  None

  	
   

  
	
  September 1, 2003

  	
   

  	
  Series
  No. 14

  	
   

  	
  $

  	
  300,000,000

  	
   

  	
  $

  	
  300,000,000

  	
   

  
	
  September 1,
  2003

  	
   

  	
  Series
  No. 15

  	
   

  	
  $

  	
  275,000,000

  	
   

  	
  $

  	
  275,000,000

  	
   

  
	
  August 1, 2005

  	
   

  	
  Series No. 16

  	
   

  	
  $

  	
  129,500,000

  	
   

  	
  $

  	
  129,500,000