EXHIBIT 10.11 

THIRD AMENDMENT TOLETTER OF CREDIT AND REIMBURSEMENT AGREEMENT 

        ThisThird Amendment to Letter of Credit and Reimbursement Agreement (this “ThirdAmendment”) is made and entered into as of the 15th day of April, 2004, by andbetween POWELL ELECTRICAL SYSTEMS, INC., a Delaware corporation(“Borrower”), successor by merger of Delta-Unibus Corp., and BANK OFAMERICA, N.A., a national banking association (“Lender”). 

WITNESSETH: 

        WHEREAS,pursuant to that certain Letter of Credit and Reimbursement Agreement (as heretoforeamended, the “Loan Agreement”) dated October 25, 2001, Lender agreed tomake certain loans to Borrower upon the terms and conditions therein contained; and 

        WHEREAS,pursuant to the terms and conditions of a First Amendment to Letter of Credit andReimbursement Agreement dated as of January 11, 2002, and a Second Amendment to Letter ofCredit and Reimbursement Agreement dated as of October 31, 2003, Borrower and Lendermodified and amended certain terms and provisions of the Loan Agreement; and 

        WHEREAS,Borrower and Lender desire to further modify and amend certain terms and provisions of theLoan Agreement. 

        NOW,THEREFORE, for good and valuable consideration, the receipt and sufficiency of which arehereby acknowledged, Borrower and Lender agree as follows: 

        1.              Amendments to Loan Agreement. Subject to and upon the full and complete          satisfaction of the terms and conditions of numerical Section 3 below, the          Loan Agreement is amended and modified as follows: 

        1.1.             All references to Delta-Unibus Corp. in the Loan Agreement, the Guaranty, and          each of the other Related Documents to which Lender is a party are deleted in          their entirety and replaced in each case with a reference to Powell Electrical          Systems, Inc. 

        2.             Reaffirmation of Representations and Warranties. To induce the Lender to          enter into this Third Amendment, Borrower hereby reaffirms, as of the date          hereof, its representations and warranties in their entirety contained in the          Loan Agreement and in all other Related Documents executed by Borrower pursuant          thereto (except to the extent such representations and warranties relate solely          to an earlier date in which case they shall have been true and accurate in all          respects as of such earlier date) and additionally represents and warrants as          follows:  

        2.1.             The execution and delivery of this Third Amendment and the performance by          Borrower of its obligations under this Third Amendment and the Loan Agreement as          amended hereby are within Borrower’s powers, have been duly authorized by          all necessary action, have received all necessary governmental and other          approvals (if any shall be required), and do not and will not contravene or          conflict with the governance documents of Borrower or any provision of law, any          presently existing requirement or restriction imposed by any judicial, arbitral,          regulatory or governmental instrumentality or constitute a default under, or          result in the creation or imposition of any lien other than a lien permitted by          the terms of the Loan Agreement upon any property or assets of Borrower or any          Guarantor under, any agreement, instrument or indenture by which Borrower or any          Guarantor is bound;   

        2.2.             This Third Amendment has been duly executed and delivered on behalf of Borrower          and this Third Amendment and the Loan Agreement, as amended hereby, are the          legal, valid and binding obligations of Borrower, enforceable in accordance with          their terms subject as to enforcement only to bankruptcy, insolvency,          reorganization, moratorium or other similar laws and equitable principles          affecting the enforcement of creditors’ rights generally; and   

        2.3.             No Default or Event of Default has occurred and is continuing after giving          effect to this Third Amendment.  

        3.             Conditions. The effectiveness of this Third Amendment is subject to the          following conditions, all in form and substance satisfactory to the Lender: 

        3.1.             The Lender shall have received and approved: