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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 TjDzDVmL0zD+acSG0UneNj/0mTRFZS4G8di/Hc1KSZ090Gs7GJGwlTybPJeVjbPB
 39sG+g+wafXLc3IjTiiTdg==

<SEC-DOCUMENT>0000097854-11-000018.txt : 20110301
<SEC-HEADER>0000097854-11-000018.hdr.sgml : 20110301
<ACCEPTANCE-DATETIME>20110301160429
ACCESSION NUMBER:		0000097854-11-000018
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20110225
FILED AS OF DATE:		20110301
DATE AS OF CHANGE:		20110301

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			RAINES J N
		CENTRAL INDEX KEY:			0001198357

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-04682
		FILM NUMBER:		11651624

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			THOMAS & BETTS CORP
		CENTRAL INDEX KEY:			0000097854
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRIC LIGHTING & WIRING EQUIPMENT [3640]
		IRS NUMBER:				221326940
		STATE OF INCORPORATION:			TN
		FISCAL YEAR END:			1209

	BUSINESS ADDRESS:	
		STREET 1:		8155 T&B BOULEVARD
		CITY:			MEMPHIS
		STATE:			TN
		ZIP:			38125
		BUSINESS PHONE:		9012525000

	MAIL ADDRESS:	
		STREET 1:		8155 T&B BOULEVARD
		CITY:			MEMPHIS
		STATE:			TN
		ZIP:			38125
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2011-02-25</periodOfReport>

    <issuer>
        <issuerCik>0000097854</issuerCik>
        <issuerName>THOMAS &amp; BETTS CORP</issuerName>
        <issuerTradingSymbol>TNB</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001198357</rptOwnerCik>
            <rptOwnerName>RAINES J N</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>8155 T&amp;B BOULEVARD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MEMPHIS,</rptOwnerCity>
            <rptOwnerState>TN</rptOwnerState>
            <rptOwnerZipCode>38125</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP-General Counsel &amp; Secretary</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2011-02-25</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>7314</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>55.3178</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>44909</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2011-02-28</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>11000</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>55.4328</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>33909</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">This transaction was executed in multiple trades at prices ranging from $55.200 to $55.520.  The price reported reflects the weighted average sale price.  The reporting person hereby undertakes to provide upon request to the Securities and Exchange Commission full information regarding the number of shares and prices at which the transaction was effected.</footnote>
        <footnote id="F2">This transaction was executed in multiple trades at prices ranging from $55.10 to $55.60.  The price reported reflects the weighted average sale price.  The reporting person hereby undertakes to provide upon request to the Securities and Exchange Commission full information regarding the number of shares and prices at which the transaction was effected.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>W. David Smith, Jr.,  Attorney-in-Fact</signatureName>
        <signatureDate>2011-03-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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