Except for attorneys, the board of public utilities shall make all appointments and hire all officers, agents, servants and employees in the waterworks and electric-light plant and fix their compensation and determine their qualification, and shall have regard alone to relative capacity of applicants, their moral, physical and health qualifications, and when appropriate, their qualifications for manual labor. All appointments shall be made on the basis of their merit alone, and no appointment shall ever be made on account of political services or affiliations. Such officers, agents, servants and employees shall serve at the pleasure of the board. The board shall have no power to retain or pay attorneys or obtain legal services except as herein provided. All legal services needed by the board shall be provided by the city attorney’s office. The cost of such services shall be paid by the city treasurer acting in the capacity of ex officio treasurer of the board from funds of the board upon presentation of vouchers or warrants authorized by the city commission.