N.J. Stat. § 18A:8-30
The membership of the board of any consolidated school district heretofore created, in which such membership has not been determined by apportionment, shall be selected as heretofore, but in any such district there may be adopted the apportionment provisions of this chapter at any annual school election by approval of a majority of the votes cast on such proposition.
The proposition shall be placed on the ballots to be used at such election whenever a petition requesting the submission of such proposition, signed by not less than five per cent of the registered voters of the consolidated district, shall have been filed with the secretary at least 20 days prior to the date fixed for the holding thereof.
If such proposition shall be adopted, the county superintendent or county superintendents of the county or counties, in which the district is situate, shall apportion the membership of the board of the consolidated district in accordance with this chapter, beginning with the next annual election, and as the terms of the respective members of the board in office shall expire, and thereafter the members of said board shall be elected accordingly.
N.J.S. § 18A:8-30