November 20, 2009

Thomas & Betts Corporation

8155 T&B Boulevard

Memphis, Tennessee 38125

Ladies and Gentlemen:

We have acted as counsel for Thomas & Betts Corporation, a Tennessee corporation (the “Company”), in connection with the Registration Statement on Form S-3 (File No. 333-155908) (the “Registration Statement”) filed by the Company with the Securities and Exchange Commission pursuant to the Securities Act of 1933, as amended (the “Securities Act”), for the registration of $250,000,000 aggregate principal amount of its 5.625% notes due 2021 (the “Notes”). The Notes are to be issued pursuant to the provisions of an indenture dated as of August 1, 1998, as supplemented by Supplemental Indenture No. 3 dated as of November 23, 2009 (the “Indenture”) between the Company and The Bank of New York Mellon Trust Company, N.A., as Trustee (the “Trustee”).

We, as your counsel, have examined originals or copies, certified or otherwise identified to our satisfaction, of such documents, corporate records, certificates of public officials and other instruments as we have deemed necessary or advisable for the purpose of rendering this opinion.

Based upon the foregoing, we advise you that, in our opinion, when the Notes have been duly authorized, executed, authenticated, issued and delivered in accordance with the Indenture against payment therefor, the Notes will constitute valid and binding obligations of the Company, enforceable in accordance with their terms, subject to applicable bankruptcy, insolvency and similar laws affecting creditors’ rights generally, concepts of reasonableness and equitable principles of general applicability, and will be entitled to the benefits of the Indenture pursuant to which such Notes are to be issued, provided that we express no opinion as to the enforceability of any waiver of rights under any usury or stay law.

In connection with the opinion expressed above, we have assumed that, each party to the Indenture and the Notes (collectively, the “Documents”) has been duly incorporated and is validly existing and in good standing under the laws of its jurisdiction of organization. In addition, we have assumed that the execution, delivery and performance by each party thereto of each Document to which it is a party (a) are within its corporate powers, (b) do not contravene, or constitute a default under, the certificate of incorporation or bylaws or other constitutive

Thomas & Betts Corporation

November 20, 2009

documents of such party, (c) require no action by or in respect of, or filing with, any governmental body, agency or official and (d) do not contravene, or constitute a default under, any provision of applicable law or regulation or any judgment, injunction, order or decree or any agreement or other instrument binding upon such party, provided that we make no such assumption to the extent that we have specifically opined as to such matters with respect to the Company, and (ii) each Document is a valid, binding and enforceable agreement of each party thereto (other than as expressly covered above in respect of the Company).

We are members of the Bar of the State of New York and the foregoing opinion is limited to the laws of the State of New York.

We hereby consent to the filing of this opinion as an exhibit to the Registration Statement referred to above and further consent to the reference to our name under the caption “Legal Matters” in the prospectus, which is a part of the Registration Statement. In giving this consent, we do not admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act.

This opinion is rendered solely to you in connection with the above matter. This opinion may not be relied upon by you for any other purpose or relied upon by or furnished to any other person without our prior written consent.

Very truly yours,

/s/ Davis Polk & Wardwell LLP