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): March 12, 2013

CAROLINA POWER & LIGHT COMPANY

d/b/a Progress Energy Carolinas, Inc.

(Exact Name of Registrant as Specified in its Charter)

410 South Wilmington Street, Raleigh, North Carolina 27601-1748

(Address of Principal Executive Offices, including Zip Code)

(704) 382-3853

(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:

On March 12, 2013, Carolina Power & Light Company d/b/a Progress Energy Carolinas, Inc. (the “Company”) consummated the issuance and sale of the securities described below pursuant to an underwriting agreement, dated as of March 7, 2013 (the “Underwriting Agreement”), with Barclays Capital Inc., BNP Paribas Securities Corp., Credit Suisse Securities (USA) LLC and RBS Securities Inc., as representatives of the several underwriters named therein (the “Underwriters”), pursuant to which the Company agreed to issue and sell to the Underwriters $500,000,000 aggregate principal amount of the Company’s First Mortgage Bonds, 4.10% Series due 2043 (the “Mortgage Bonds”). The Mortgage Bonds were sold to the Underwriters at discounts to their principal amounts. The Mortgage Bonds were issued under the Mortgage and Deed of Trust (dated as of May 1, 1940) with The Bank of New York Mellon (formerly Irving Trust Company) (the “Corporate Trustee”) and Tina D. Gonzalez (successor to Frederick G. Herbst) (together with the Corporate Trustee, the “Trustees”), as Trustees, as supplemented from time to time, including by the Eightieth Supplemental Indenture (the “Supplemental Indenture”), dated as of March 1, 2013, between the Company and the Trustees, relating to the Mortgage Bonds (collectively, the “Mortgage”). The disclosure in this Item 8.01 is qualified in its entirety by the provisions of the Mortgage, the Supplemental Indenture, which together with the form of global note evidencing the Mortgage Bonds, is filed as Exhibit 4.1 hereto, and the Underwriting Agreement, which is filed as Exhibit 99.1 hereto. Such exhibits are incorporated herein by reference. Also, in connection with the issuance and sale of the Mortgage Bonds, the Company is filing a legal opinion regarding the validity of the Mortgage Bonds as Exhibit 5.1 to this Form 8-K for the purpose of incorporating the opinion into the Company’s Registration Statement No. 333-179835-02.

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SIGNATURE

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

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EXHIBIT INDEX

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