Utilities. The developer shall install its distribution supply lines, services and street lighting supply facilities underground in accordance with the serving utilities' specifications and with the provisions of the applicable standard terms and conditions incorporated as a part of its tariff as the same are then on file with the State of New Jersey Board of Public Utility Commissioners, provided however, that for good cause shown the Planning Board may waive this requirement and provided further that lots which, in such subdivisions or site plans, abut existing streets where overhead electric or telephone distribution supply lines have heretofore been installed on any portion of the street involved, may be supplied with electric and telephone service from those overhead lines or extensions thereof, but the service connections from the utilities' overhead lines may be installed underground.