UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d) OF THE

SECURITIES EXCHANGE ACT OF 1934

Date of Report (date of earliest event reported): June 22, 2012

EATON CORPORATION

(Exact name of registrant as specified in its charter)

Eaton Center

Cleveland, Ohio 44114

(Address of principal executive offices)

(216) 523-5000

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

Item 7.01. Regulation FD Disclosure.

On May 21, 2012, Eaton Corporation, an Ohio corporation (“Eaton”), and Cooper Industries plc, a public limited company organized under the laws of Ireland (“Cooper”), announced (the “Announcement”), pursuant to Rule 2.5 of the Irish Takeover Panel Act, 1997, Takeover Rules, 2007 (as amended) (the “Irish Takeover Rules”), that they had entered into a definitive agreement pursuant to which Eaton will acquire Cooper (the “Acquisition”).

On June 22, 2012, Eaton Corporation Limited (“New Eaton”) filed with the SEC a registration statement on Form S-4 in connection with the Acquisition which included a joint proxy statement of Eaton and Cooper (the “Form S-4”). The Form S-4 has not yet been declared effective by the SEC.

The Announcement and the Form S-4 each contain certain statements regarding the synergies that may result from the Acquisition; in section 7 of the Announcement (“Synergies”) and in the “Recommendation of the Eaton Board of Directors and Eaton’s Reasons for the Transaction” and the “Recommendation of the Cooper Board of Directors and Cooper’s Reasons for the Transaction” sections of the Form S-4 (the “Synergy Statements”).

Solely for the purposes of complying with Rule 19.3(b)(ii) of the Irish Takeover Rules, New Eaton’s reporting accountant, Ernst & Young LLP, and financial advisors, Citigroup Global Markets Inc. and Morgan Stanley & Co. LLC, have delivered reports confirming that the Synergy Statements have been made with due care and consideration (the “Reports”).

On June 22, 2012, Eaton issued an announcement containing a link to the full text of the Reports (the “June 22 Announcement”). The full text of the June 22 Announcement is furnished as Exhibit 99.1 to this report. The full text of the report of Ernst & Young LLP is furnished as Exhibit 99.2 to this report. The full text of the report of Citigroup Global Markets Inc. and Morgan Stanley & Co. LLC is furnished as Exhibit 99.3 to this report.

As provided in General Instruction B.2 of Form 8-K, the information in this Item 7.01 and Exhibits 99.1, 99.2 and 99.3 incorporated herein shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, nor shall they be deemed to be incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, except as shall be expressly set forth by specific reference in such a filing.

Item 9.01 Financial Statements and Exhibits.

NO OFFER OR SOLICITATION

This communication is not intended to and does not constitute an offer to sell or the solicitation of an offer to subscribe for or buy or an invitation to purchase or subscribe for any securities or the solicitation of any vote or approval in any jurisdiction pursuant to the Acquisition or otherwise, nor shall there be any sale, issuance or transfer of securities in any jurisdiction in contravention of applicable law. No offer of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended.

IMPORTANT ADDITIONAL INFORMATION HAS BEEN AND WILL BE FILED WITH THE SEC

New Eaton has filed with the SEC a registration statement on Form S-4 that includes the preliminary Joint Proxy Statement of Eaton and Cooper that also constitutes a Prospectus of New Eaton. Eaton and Cooper plan to mail to their respective shareholders (and to Cooper Equity Award Holders for information only) the definitive Joint Proxy Statement/Prospectus (including the Scheme) in connection with the transactions. INVESTORS AND SHAREHOLDERS ARE URGED TO READ THE JOINT PROXY STATEMENT/PROSPECTUS (INCLUDING THE SCHEME) AND OTHER RELEVANT DOCUMENTS FILED OR TO BE FILED WITH THE SEC CAREFULLY WHEN THEY BECOME AVAILABLE BECAUSE THEY CONTAIN OR WILL CONTAIN IMPORTANT INFORMATION ABOUT EATON, COOPER, NEW EATON, THE TRANSACTIONS AND RELATED MATTERS. Investors and security holders may obtain free copies of the preliminary Joint Proxy Statement/Prospectus (including the Scheme) and other documents filed with the SEC by New Eaton, Eaton and Cooper through the website maintained by the SEC at www.sec.gov. In addition, investors and shareholders may obtain free copies of the Joint Proxy Statement/Prospectus (including the Scheme) and other documents filed by Eaton and New Eaton with the SEC by contacting Eaton Investor Relations at Eaton Corporation, 1111 Superior Avenue, Cleveland, OH 44114 or by calling (888) 328-6647, and may obtain free copies of the Joint Proxy Statement/Prospectus (including the Scheme) and other documents filed by Cooper by contacting Cooper Investor Relations at c/o Cooper US, Inc., P.O. Box 4466, Houston, Texas 77210 or by calling (713) 209-8400.

PARTICIPANTS IN THE SOLICITATION

Cooper, Eaton and New Eaton and their respective directors and executive officers may be deemed to be participants in the solicitation of proxies from the respective shareholders of Cooper and Eaton in respect of the transactions contemplated by the Joint Proxy

Statement/Prospectus. Information regarding the persons who may, under the rules of the SEC, be deemed participants in the solicitation of the respective shareholders of Cooper and Eaton in connection with the proposed transactions, including a description of their direct or indirect interests, by security holdings or otherwise, is set forth in the Joint Proxy Statement/Prospectus. Information regarding Cooper’s directors and executive officers is contained in Cooper’s Annual Report on Form 10-K for the year ended December 31, 2011 and its Proxy Statement on Schedule 14A, dated March 13, 2012, which are filed with the SEC. Information regarding Eaton’s directors and executive officers is contained in Eaton’s Annual Report on Form 10-K for the year ended December 31, 2011 and its Proxy Statement on Schedule 14A, dated March 16, 2012, which are filed with the SEC.

EATON SAFE HARBOR STATEMENT

This communication may contain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 concerning Eaton, New Eaton, the Acquisition and other transactions contemplated by the Transaction Agreement, our acquisition financing, our long-term credit rating and our revenues and operating earnings. These statements or disclosures may discuss goals, intentions and expectations as to future trends, plans, events, results of operations or financial condition, or state other information relating to Eaton or New Eaton, based on current beliefs of management as well as assumptions made by, and information currently available to, management. Forward-looking statements generally will be accompanied by words such as “anticipate,” “believe,” “plan,” “could,” “estimate,” “expect,” “forecast,” “guidance,” “intend,” “may,” “possible,” “potential,” “predict,” “project” or other similar words, phrases or expressions. These forward-looking statements are subject to various risks and uncertainties, many of which are outside of our control. Therefore, you should not place undue reliance on such statements. Factors that could cause actual results to differ materially from those in the forward-looking statements include adverse regulatory decisions; failure to satisfy other closing conditions with respect to the Acquisition; the risks that the new businesses will not be integrated successfully or that we will not realize estimated cost savings and synergies; our ability to refinance the bridge loan on favorable terms and maintain our current long-term credit rating; unanticipated changes in the markets for our business segments; unanticipated downturns in business relationships with customers or their purchases from Eaton; competitive pressures on our sales and pricing; increases in the cost of material, energy and other production costs, or unexpected costs that cannot be recouped in product pricing; the introduction of competing technologies; unexpected technical or marketing difficulties; unexpected claims, charges, litigation or dispute resolutions; new laws and governmental regulations. The foregoing list of factors is not exhaustive. You should carefully consider the foregoing factors and the other risks and uncertainties that affect our business described in our Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and other documents filed from time to time with the SEC. We do not assume any obligation to update these forward-looking statements.

No statement in this communication is intended to constitute a profit forecast for any period, nor should any statements be interpreted to mean that earnings or earnings per share will necessarily be greater or lesser than those for the relevant preceding financial periods for Eaton.

STATEMENT REQUIRED BY THE TAKEOVER RULES

The directors of Eaton accept responsibility for the information contained in this communication. To the best of the knowledge and belief of the directors of Eaton (who have taken all reasonable care to ensure such is the case), the information contained in this communication is in accordance with the facts and does not omit anything likely to affect the import of such information.

Persons interested in 1% or more of any relevant securities in Eaton or Cooper may from the date of this announcement have disclosure obligations under Rule 8.3 of the Irish Takeover Panel Act, 1997, Takeover Rules 2007 (as amended).

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Date: June 22, 2012

Index of Exhibits