(a) The board of public utilities shall consist of six members, three of which shall be nominated and elected by the city at large and three of which shall be elected by the qualified electors of the city within each of the districts established pursuant to subsection (b). Members of the board shall be elected on a nonpartisan basis. Members elected to the board of public utilities after the effective date of this act shall hold their offices for terms of four years, and until their successors are elected and qualified. Each of the members elected from districts shall be qualified voters of the districts from which elected. Elections of members of the board shall be held at the general election in odd-numbered years.

(b) The board shall elect from its own number a president and vice-president and shall appoint a secretary. Any vacancy occurring in the board shall be filled by a majority vote of the members remaining on the board. Where a vacancy has occurred in the membership of any board of public utilities, a member selected to fill such vacancy shall serve until the next November in odd-numbered years election, at which time a successor shall be elected to serve the remainder of the unexpired term, if any.