Wis. Stat. § 111.54: Conciliation.

If in any case of a labor dispute between a public utility employer and its employees, the collective bargaining process reaches an impasse and stalemate, with the result that the employer and the employees are unable to effect a settlement thereof, then either party to the dispute may petition the commission to appoint a conciliator from the panel, provided for by s. 111.53. Upon the filing of such petition, the commission shall consider the same, and if in its opinion, the collective bargaining process, notwithstanding good faith efforts on the part of both sides to such dispute, has reached an impasse and stalemate and such dispute, if not settled, will cause or is likely to cause the interruption of an essential service, the commission shall appoint a conciliator from the panel to attempt to effect the settlement of such dispute. The conciliator so named shall expeditiously meet with the disputing parties and shall exert every reasonable effort to effect a prompt settlement of the dispute.