Section 22H. If underground construction is necessary to provide replacement facilities for any poles and overhead wires and associated overhead structures removed pursuant to any ordinance or by-law enacted pursuant to section twenty-two D the utility shall be responsible to furnish in connection with such replacement facilities only that portion of the conduits, conductors and associated equipment required to be furnished by it under its applicable rules, regulations and tariffs on file with the department (hereinafter called the ''utility's service facilities''); provided, however, that the utility shall by its tariff offer to carry its lines up to any structure which is to receive service or a distance of fifty feet from the street, whichever is the lesser; and provided, further, that if any ordinance or by-law adopted pursuant to section twenty-two D so provides, any utility in providing underground replacement facilities for any poles and overhead wires and associated overhead structures shall install customer's service facilities. Underground construction by the utility, or by or on behalf of any municipality, pursuant to any cooperation agreement entered into pursuant to section twenty-two E shall be accomplished in accordance with the rules and regulations authorized by the department, and shall be scheduled so as to be completed at or prior to removal of such poles and overhead wires and associated overhead structures as are being removed.