Original General Order 128
            Section
            IV
        
Requirements For Communication Systems
43.3 Clearances and Depths
Buried communication cables and conductors for public use shall be subject to the same clearance and depth requirements as specified for duct systems in Rules 41.4-A, 41.4-C and 41.4-D. In addition, separations from supply system ducts and buried cables or conductors shall be as follows:
            
            A.    Independently
            Installed
             
            
             Buried communication
            cables and conductors, when independently installed, shall be
            separated where practicable from supply system ducts and
            buried cables or conductors by not less than 3 inches of
            concrete, 4 inches of brick masonry, or 12 inches of
            earth.
             
        
            
            B.    Concurrently
            Installed
            
            
            
            Buried communication cables and
            conductors, when concurrently installed, and with mutual
            agreement of the parties involved, may have separations from
            supply system ducts and buried cables or conductors less than
            those specified in Rule 43.3-A as
            follows:
             
        
(1) Random Separation from Buried Supply Cables and Conductors of Not Over 300 Volts to Ground: No physical separation of supply and communication systems is required when the supply circuit includes an effectively grounded neutral conductor and the maximum voltage to ground of the circuit does not exceed 300 volts provided that all grounded conductors, sheaths, or shields of each system appearing at connecting or terminating points are bonded and such bonds of the two systems are interconnected wherever practicable. (See Appendix B, Fig. 5)