The time within which any pleading, motion, notice, brief, or exceptions may be filed, or the time within which any act is required to be performed or may be performed, as provided by any rule or order of the Commission, shall be so computed as to exclude the first day and include the last day; provided, that when the last day of any such period falls on Saturday, Sunday, a legal holiday under the laws of this State, or a day on which the offices of the Commission for any reason are not open for business, the computation of time shall omit such day and begin on the first day thereafter which does not fall on any such day. (Not applicable in the computing of time for filing transportation tariffs and minimum rate schedules. See Rule R4-10.)

(NCUC Docket No. M-100, Sub 3, 7/30/64.)