EXHIBIT 5.1

                              Quarles & Brady LLP
                           411 East Wisconsin Avenue
                        Milwaukee, Wisconsin 53202-4497
                           Telephone:  414-277-5000
                              Fax:  414-271-3552

                                           September 18, 2001

Wisconsin Energy Corporation
231 West Michigan Street
Milwaukee, WI  53203

Ladies and Gentlemen:

     We are providing this opinion in connection with the Registration Statement
of Wisconsin Energy Corporation (the "Company") on Form S-3 (the "Registration
Statement") to be filed with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Act"), with
respect to the proposed offering from time to time, together or separately, of
up to $500,000,000 of the Company's (i) unsecured debt securities (the "Debt
Securities"), (ii) Preferred Stock, par value $.01 per share (the "Preferred
Stock"), (iii) Preferred Securities of WEC Capital Trust II (the "WEC Trust"),
and (iv) the guarantee by the Company of any Preferred Securities issued by the
WEC Trust pursuant to a Guarantee Agreement to be executed by the Company (the
"Guarantees"). The Debt Securities, the Preferred Stock, the Preferred
Securities and the Guarantees are collectively referred to herein as the
"Offered Securities."

     We have examined (i) the Registration Statement; (ii) the Company's
Restated Articles of Incorporation and Bylaws, as amended to date; (iii) the
Indenture for Debt Securities dated as of March 15, 1999 (including, as
exhibits, forms of Registered Security and Bearer Security thereunder) between
the Company and Bank One Trust Company, National Association (successor to The
First National Bank of Chicago), as Trustee (the "Indenture"), providing for the
issuance of the Debt Securities from time to time in one or more series pursuant
to the terms of one or more Securities Resolutions (as defined in the Indenture)
creating such series; (iv) other exhibits to the Registration Statement relating
to the Offered Securities; (v) corporate proceedings of the Company relating to
the Registration Statement, the Indenture and the transactions contemplated
thereby; and (vi) such other documents, and such matters of law, as we have
deemed necessary in order to render this opinion.

     On the basis of and subject to the foregoing, we advise you that, in our
opinion:

     1.   The Company is a corporation validly existing under the laws of the
          State of Wisconsin.


Wisconsin Energy Corporation
Page 2
September 18, 2001

     2.   When (i) the Registration Statement has become effective under the
          Act, (ii) the terms of any class or series of Offered Securities have
          been authorized by appropriate action of the Company in a manner that
          would not violate any applicable law or result in a default under or
          breach of any agreement or instrument binding upon the Company and so
          as to comply with any requirement or restriction imposed by a court or
          a governmental or regulatory body having jurisdiction over the
          Company, (iii) any such class or series of Offered Securities has been
          duly issued and sold, and payment has been received for such Offered
          Securities in the manner contemplated in the Registration Statement
          and any prospectus supplement relating thereto, then (a) the Preferred
          Stock will be validly issued, fully paid and nonassessable, subject to
          the personal liability which may be imposed on shareholders by statute
          for debts owing to employees as described below, and (b) the Debt
          Securities and the Guarantees will be duly authorized and legally
          issued and will constitute valid and binding obligations of the
          Company enforceable in accordance with their respective terms subject
          to (x) bankruptcy, insolvency, reorganization, fraudulent transfer,
          moratorium and other similar laws now or hereafter in effect relating
          to or affecting creditors' rights generally, (y) general principles of
          equity (regardless of whether considered in a proceeding at law or in
          equity) and (z) the qualification that the remedy of specific
          performance and injunctive or other forms of equitable relief may be
          subject to equitable defenses and to the discretion of the court
          before which any proceeding may be brought.

     Our opinion with respect to the nonassessability of the Preferred Stock is
subject to the personal liability which  may be imposed on shareholders by
Section 180.0622(2)(b) of the Wisconsin Business Corporation Law, as judicially
interpreted, for debts owing to employees for services performed, but not
exceeding six months service in any one case.

     As to the legality of the Preferred Securities which may be issued by the
WEC Trust, we understand that, in the event of such an issuance, you will
receive an opinion of special Delaware counsel to the WEC Trust and the Company.

     We consent to the filing of this opinion as an exhibit to the Registration
Statement and to the reference to our firm under the caption "Certain Legal
Matters" in the Prospectus constituting a part thereof.  In giving our consent,
we do not admit that we are "experts" within the meaning of Section 11 of the
Act, or that we come within the category of persons whose consent is required by
Section 7 of the Act or the rules and regulations of the Commission thereunder.

                                       Very truly yours,

                                       /s/ Quarles & Brady LLP

                                       QUARLES & BRADY LLP