Connection of the building sewer into the public sewer shall be made at the “Y” branch, if such branch is available at a suitable location. If no properly located “Y” branch is available, a saddle “Y” shall be installed at the location specified by the Superintendent and Building Inspector. At no time shall a building sewer be constructed so as to enter a manhole unless special written permission is received from the Superintendent and Building Inspector and in accordance with the Superintendent’s and Building Inspector’s direction if such connection is approved.