Mass. Gen. Laws ch. 155 § 5A
If, when the department of public utilities or the department of telecommunications and cable, as required by law, approves an issue of stock, bonds, coupon notes or other evidences of indebtedness of a company under its supervision, or passes upon the price, rates, charges or service of such company, it determines that the provision made by such company for the depreciation of its property has been inadequate, the department shall order such company to set aside out of earnings such allowances for depreciation and for such period or periods as the department may from time to time prescribe. All moneys required by such order to be so set aside shall be kept as a separate fund and shall not, without the further order of the department, be used for any other purpose than for renewals other than ordinary repairs, or for extensions, reconstruction and enlargements of and additions to plant, and the department shall prescribe in its order such requirements relative to the creation and maintenance of such fund and its devotion to such aforesaid authorized uses as it may deem advisable. All orders and decisions of the department under the provisions of this section shall be enforced as provided in section sixteen of chapter one hundred and sixty-four.
Mass. Gen. Laws ch. 155, § 5A