<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2008-03-05</periodOfReport>

    <dateOfOriginalSubmission>2008-03-06</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000909109</issuerCik>
        <issuerName>PHILADELPHIA CONSOLIDATED HOLDING CORP</issuerName>
        <issuerTradingSymbol>PHLY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000937439</rptOwnerCik>
            <rptOwnerName>MAGUIRE JAMES J ET AL</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>SUITE 100</rptOwnerStreet1>
            <rptOwnerStreet2>ONE BALA PLAZA</rptOwnerStreet2>
            <rptOwnerCity>BALA CYNWYD</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>19004</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman of the BOD</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock (no par value)</value>
            </securityTitle>
            <transactionDate>
                <value>2008-03-05</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>60000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>30.81</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9715109</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock (no par value)</value>
            </securityTitle>
            <transactionDate>
                <value>2008-03-05</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>30000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>30.819</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9695109</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock (no par value)</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3006030</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">These purchases were made from the Company's Chief Financial Officer.</footnote>
        <footnote id="F2">Of these shares, 5,251,500 are owned jointly by Mr. Maguire and his wife, Frances M. Maguire.</footnote>
        <footnote id="F3">The reporting person's Form 4 filed on March 6, 2008 inadvertently showed 2,956,030 shares, rather than 3,006,030 shares  (the correct amount), as being indirectly beneficially owned by the reporting person and shows 9,745,109 shares, rather than 9,695,109 shares (the correct amount), as being directly beneficially owned by the reporting person.</footnote>
        <footnote id="F4">Of these shares:  989,836 shares are held by trusts of which Ms. Frances M. Maguire, Mr. James J. Maguire's wife, is the trustee and the children of Ms. Maguire and Mr. James J. Maguire are the beneficiaries; 603,396 shares are held in family trusts of which Mr. Maguire's wife is co-trustee; 824,798 shares are owned by the Maguire Foundation, of which Mr. Maguire is co-director with his wife, and 588,000 shares are owned of record by Mr. Maguire's wife.  Mr. Maguire disclaims beneficial ownership of these 3,006,030 shares and the filing of this report is not an admission that he is a beneficial owner of these shares for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Craig P. Keller, Attorney-In-Fact</signatureName>
        <signatureDate>2008-07-31</signatureDate>
    </ownerSignature>
</ownershipDocument>
