Unless otherwise specified, any letter or notice from the Board directing investigation of any matter under its jurisdiction must be complied with by the utility and a report received by the Board within 15 days from the date of the letter or notice. If circumstances prevent compliance with this section, the utility must advise the Board, in writing within the above prescribed period, of its inability to comply and the reasons therefor.
N.J. Admin. Code § 14:1-10.4