The board shall employ a competent attorney to serve as its general counsel, and assistants to the general counsel as it finds necessary for the full and efficient discharge of its duties. The general counsel is the attorney for, and legal advisor of, the board and is exempt from the merit system provisions of chapter 8A, subchapter IV. Assistants to the general counsel are subject to the merit system provisions of chapter 8A, subchapter IV. The general counsel or an assistant to the general counsel shall provide the necessary legal advice to the board in all matters and represent the board in all actions instituted in a state or federal court challenging the validity of a rule or order of the board. The existence of a fact which disqualifies a person from election or from acting as a utilities board member disqualifies the person from employment as general counsel or assistant general counsel. The general counsel shall devote full time to the duties of the office. During employment the counsel shall not be a member of a political committee, contribute to a political campaign fund other than through the income tax checkoff for contributions to the presidential election campaign fund, participate in a political campaign, or be a candidate for a political office.