N.D. Cent. Code § 40-45-25
A police officer employed in the police department of a city having a population of ten thousand or more inhabitants shall not be required to remain on duty for periods of time which will aggregate in each month more than an average of eight hours per day. No single period of time or shift shall exceed twenty-four hours in length except that in case of serious emergency, the police officer may be required to remain on duty until the emergency has passed, if the officer is ordered to do so by the chief of the department or the person acting in the chief's place. The provisions of this section shall not apply to the chief or other persons in command of a police department or to police officers who are employed subject to call only.
N.D.C.C. § 40-45-25