-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 1qfs2hf+aKQhtCPfhKj4vg==

<SEC-DOCUMENT>0001104659-03-016806.txt : 20030806
<SEC-HEADER>0001104659-03-016806.hdr.sgml : 20030806
<ACCEPTANCE-DATETIME>20030806104604
ACCESSION NUMBER:		0001104659-03-016806
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030801
FILED AS OF DATE:		20030806

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			TC PIPELINES LP
		CENTRAL INDEX KEY:			0001075607
		STANDARD INDUSTRIAL CLASSIFICATION:	NATURAL GAS TRANSMISSION [4922]
		IRS NUMBER:				522135448
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		110 TURNPIKE ROAD SUITE 203
		CITY:			WESTBOROUGH
		STATE:			MA
		ZIP:			01581
		BUSINESS PHONE:		5088717046

	MAIL ADDRESS:	
		STREET 1:		110 TURNPIKE RD
		STREET 2:		SUITE 203
		CITY:			WESTBOROUGH
		STATE:			MA
		ZIP:			01581

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			TRANSCANADA PIPELINES LTD
		CENTRAL INDEX KEY:			0000099070
		STANDARD INDUSTRIAL CLASSIFICATION:	NATURAL GAS TRANSMISSION [4922]
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-26091
		FILM NUMBER:		03825300

	BUSINESS ADDRESS:	
		STREET 1:		450 I STREET SW
		STREET 2:		P O BOX 1000 STATION M
		CITY:			CALGARY ALBERTA
		STATE:			A0
		ZIP:			T2P 5H1
		BUSINESS PHONE:		4039207669

	MAIL ADDRESS:	
		STREET 1:		450 I STREET SW
		CITY:			CALGARY ALBERTA
		STATE:			A0
		ZIP:			T2P 5H1

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			TRANSCANADA CORP
		CENTRAL INDEX KEY:			0001232384
		STANDARD INDUSTRIAL CLASSIFICATION:	NATURAL GAS TRANSMISSION [4922]
		STATE OF INCORPORATION:			A0
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-26091
		FILM NUMBER:		03825299

	BUSINESS ADDRESS:	
		STREET 1:		450 - 1ST STREET S.W.
		CITY:			CALGARY ALBERTA
		STATE:			A0
		ZIP:			T2P 5H1
		BUSINESS PHONE:		4039202000

	MAIL ADDRESS:	
		STREET 1:		450 - 1ST STREET S.W.
		CITY:			CALGARY ALBERTA
		STATE:			A0
		ZIP:			T2P 5H1
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>a4.xml
<DESCRIPTION>4
<TEXT>
<XML>
<?xml version="1.0" encoding="utf-8"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
  <periodOfReport>2003-08-01</periodOfReport>
  <notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0001075607</issuerCik>
        <issuerName>TC PIPELINES LP</issuerName>
        <issuerTradingSymbol>TCLP</issuerTradingSymbol>
  </issuer>
  <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000099070</rptOwnerCik>
            <rptOwnerName>TRANSCANADA PIPELINES LTD</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>450 I STREET SW</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CALGARY ALBERTA</rptOwnerCity>
            <rptOwnerState>A0</rptOwnerState>
            <rptOwnerZipCode>T2P 5H1</rptOwnerZipCode>
            <rptOwnerStateDescription>ALBERTA, CANADA</rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
      <isDirector>0</isDirector>
      <isOfficer>0</isOfficer>
      <isTenPercentOwner>1</isTenPercentOwner>
      <isOther>0</isOther>
    </reportingOwnerRelationship>
  </reportingOwner>
  <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001232384</rptOwnerCik>
            <rptOwnerName>TRANSCANADA CORP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>450 - 1ST STREET SW</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CALGARY</rptOwnerCity>
            <rptOwnerState>A0</rptOwnerState>
            <rptOwnerZipCode>T2P 5H1</rptOwnerZipCode>
            <rptOwnerStateDescription>ALBERTA, CANADA</rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
      <isDirector>0</isDirector>
      <isOfficer>0</isOfficer>
      <isTenPercentOwner>1</isTenPercentOwner>
      <isOther>0</isOther>
    </reportingOwnerRelationship>
  </reportingOwner>
  <nonDerivativeTable>
    <nonDerivativeTransaction>
      <securityTitle>
        <value>Common units representing limited partner interests</value>
      </securityTitle>
      <transactionDate>
        <value>2003-08-01</value>
      </transactionDate>
      <transactionCoding>
        <transactionFormType>4</transactionFormType>
        <transactionCode>C</transactionCode>
        <equitySwapInvolved>0</equitySwapInvolved>
      </transactionCoding>
      <transactionTimeliness>
        <value></value>
      </transactionTimeliness>
      <transactionAmounts>
        <transactionShares>
          <value>936435</value>
        </transactionShares>
        <transactionPricePerShare>
          <value>0</value>
          <footnoteId id="F1"/>
        </transactionPricePerShare>
        <transactionAcquiredDisposedCode>
          <value>A</value>
        </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <postTransactionAmounts>
        <sharesOwnedFollowingTransaction>
          <value>4672870</value>
        </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
        <directOrIndirectOwnership>
          <value>I</value>
        </directOrIndirectOwnership>
        <natureOfOwnership>
          <value>See Footnote</value>
          <footnoteId id="F5"/>
        </natureOfOwnership>
      </ownershipNature>
    </nonDerivativeTransaction>
  </nonDerivativeTable>
  <derivativeTable>
    <derivativeTransaction>
      <securityTitle>
        <value>Subordinated units</value>
      </securityTitle>
      <conversionOrExercisePrice>
        <value>0</value>
        <footnoteId id="F1"/>
      </conversionOrExercisePrice>
      <transactionDate>
        <value>2003-08-01</value>
      </transactionDate>
      <transactionCoding>
        <transactionFormType>4</transactionFormType>
        <transactionCode>J</transactionCode>
        <equitySwapInvolved>0</equitySwapInvolved>
      </transactionCoding>
      <transactionTimeliness>
        <value></value>
      </transactionTimeliness>
      <transactionAmounts>
        <transactionShares>
          <value>936435</value>
        </transactionShares>
        <transactionPricePerShare>
          <value>0</value>
          <footnoteId id="F2"/>
        </transactionPricePerShare>
        <transactionAcquiredDisposedCode>
          <value>A</value>
        </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <exerciseDate>
        <value>2003-08-01</value>
        <footnoteId id="F2"/>
      </exerciseDate>
      <expirationDate>
        <value>2003-08-01</value>
        <footnoteId id="F3"/>
      </expirationDate>
      <underlyingSecurity>
        <underlyingSecurityTitle>
          <value>Common units</value>
        </underlyingSecurityTitle>
        <underlyingSecurityShares>
          <value>936435</value>
        </underlyingSecurityShares>
      </underlyingSecurity>
      <postTransactionAmounts>
        <sharesOwnedFollowingTransaction>
          <value>0</value>
          <footnoteId id="F4"/>
        </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
        <directOrIndirectOwnership>
          <value>I</value>
        </directOrIndirectOwnership>
        <natureOfOwnership>
          <value>See Footnote</value>
          <footnoteId id="F5"/>
        </natureOfOwnership>
      </ownershipNature>
    </derivativeTransaction>
    <derivativeTransaction>
      <securityTitle>
        <value>Subordinated units</value>
      </securityTitle>
      <conversionOrExercisePrice>
        <value>0</value>
        <footnoteId id="F1"/>
      </conversionOrExercisePrice>
      <transactionDate>
        <value>2003-08-01</value>
      </transactionDate>
      <transactionCoding>
        <transactionFormType>4</transactionFormType>
        <transactionCode>C</transactionCode>
        <equitySwapInvolved>0</equitySwapInvolved>
      </transactionCoding>
      <transactionTimeliness>
        <value></value>
      </transactionTimeliness>
      <transactionAmounts>
        <transactionShares>
          <value>936435</value>
        </transactionShares>
        <transactionPricePerShare>
          <value>0</value>
          <footnoteId id="F2"/>
        </transactionPricePerShare>
        <transactionAcquiredDisposedCode>
          <value>D</value>
        </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <exerciseDate>
        <value>2003-08-01</value>
        <footnoteId id="F2"/>
      </exerciseDate>
      <expirationDate>
        <value>2003-08-01</value>
        <footnoteId id="F3"/>
      </expirationDate>
      <underlyingSecurity>
        <underlyingSecurityTitle>
          <value>Common units</value>
        </underlyingSecurityTitle>
        <underlyingSecurityShares>
          <value>936435</value>
        </underlyingSecurityShares>
      </underlyingSecurity>
      <postTransactionAmounts>
        <sharesOwnedFollowingTransaction>
          <value>0</value>
          <footnoteId id="F4"/>
        </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
        <directOrIndirectOwnership>
          <value>I</value>
        </directOrIndirectOwnership>
        <natureOfOwnership>
          <value>See Footnote</value>
          <footnoteId id="F5"/>
        </natureOfOwnership>
      </ownershipNature>
    </derivativeTransaction>
  </derivativeTable>
  <footnotes>
    <footnote id="F1">Subordinated units which convert to common units on a one-for-one basis.</footnote>
    <footnote id="F2">Automatic conversion of subordinated units in accordance with terms of limited partnership agreement of TC PipeLines, LP.</footnote>
    <footnote id="F3">The subordinated units do not have an expiration date.</footnote>
    <footnote id="F4">First business day after the record date for the quarter ended June 30, 2004, provided the terms of the partnership agreement are met, an additional 936,436 subordinated units will automatically convert on a one-to-one basis into common units.</footnote>
    <footnote id="F5">TC PipeLines GP, Inc. is a wholly owned subsidiary of TransCan Northern Ltd. which is a wholly owned subsidiary of TransCanada PipeLines Limited which is a subsidiary of TransCanada Corporation.  TC PipeLines GP, Inc. owns 1,872,870 common units.  TransCan Northern Ltd. owns 2,800,000 common units.  TransCanada PipeLines Limited and TransCanada Corporation are the indirect beneficial owner of 4,672,870 common units.</footnote>
  </footnotes>
  <ownerSignature>
    <signatureName>/s/ Rhondda E.S. Grant</signatureName>
    <signatureDate>2003-08-05</signatureDate>
  </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----