Exhibit 4(c) COMMITMENT AMOUNT INCREASE REQUEST November 21, 2005 Harris N.A. as Agent (the "AGENT") for the Lenders referred to below 111 West Monroe Street Chicago, Illinois 60603 Attention: Joann Holman, Director Re: Amended and Restated Credit Agreement dated as of October 14, 2005 among EMCOR Group, Inc., the Lenders party thereto and Harris N.A., as Agent (as amended, modified or supplemented from time to time, the "CREDIT AGREEMENT"). -------------------------------------- Ladies and Gentlemen: In accordance with the Credit Agreement, the Company hereby requests that the Agent consent to an increase in the aggregate Commitments (the "COMMITMENT AMOUNT INCREASE"), in accordance with Section 1.10 of the Credit Agreement, to be effected by an increase in the Commitment of The Northern Trust Company ("NORTHERN TRUST"). Capitalized terms used herein without definition shall have the same meanings herein as such terms have in the Credit Agreement. After giving effect to such Commitment Amount Increase, and upon the effectiveness of such Commitment Amount Increase, the Commitment of Northern Trust will be as set forth on Attachment I hereto. On the date hereof, the Company agrees to pay to the Agent, for the account of Northern Trust, a one-time, non-refundable upfront fee in an amount equal to $6,250. THIS AGREEMENT SHALL BE DEEMED TO BE A CONTRACTUAL OBLIGATION UNDER, AND SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF ILLINOIS. The Commitment Amount Increase shall be effective when the executed consent of the Agent is received or otherwise in accordance with Section 1.10 of the Credit Agreement, but not in any case prior to November 29, 2005. It shall be a condition to the effectiveness of the Commitment Amount Increase that (i) all fees and expenses referred to in Section 1.10 of the Credit Agreement shall have been paid and (ii) no Eurodollar Loans shall be outstanding on the date of such effectiveness. The Company hereby certifies that no Default or Event of Default has occurred and is continuing. Please indicate the Agent's consent to such Commitment Amount Increase by signing the enclosed copy of this letter in the space provided below. Very truly yours, EMCOR GROUP, INC. By: ---------------------------------- Name: ----------------------------- Title: ---------------------------- THE NORTHERN TRUST COMPANY By: ---------------------------------- Name: ----------------------------- Title: ---------------------------- The undersigned hereby consents On this 29th day of November, 2005 to the above-requested Commitment Amount Increase. HARRIS N.A., as Agent By: ----------------------------------------- Name: ------------------------------------ Title: ----------------------------------- ATTACHMENT I LENDER COMMITMENT The Northern Trust Company $15,000,000