N.J. Stat. § 34:13B-6
Whenever at the time of the passage of this act a labor contract between a utility and its employees has existed and has expired, and where services are still being performed by the said employees under the terms of said expired contract, the said employees, through their duly elected representatives, if they desire to enter into a contract with the utility or if they desire to seek changes in the terms of wages, hours or working conditions, or if the utility shall desire in any way to effect the terms of wages, working conditions, et cetera, under which employment is now being carried on then and in that case the party desiring such changes shall within ten days after the effective date of this act inform the other party in writing of the specific changes desired to be made in said terms of employment either by contract, in writing, or otherwise, and shall promptly file a copy of such demands with the State Board of Mediation.
N.J.S. § 34:13B-6