N.J. Stat. § 48:3-7.3: Investment of depreciation fund in certain securities; approval of board

No public utility shall, without the approval in writing of the board first had and obtained, invest any part of its depreciation fund in obligations or securities of any kind, except obligations and securities that are legal investments for savings banks under the laws of this state, and except obligations and securities of the underlying or subsidiary public utility corporations of this state, of such public utility.