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 systems 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 communications 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) .
C.    Depths
                     
                                           
    
Communication cables shall be installed 
  at a minimum depth below the surface under which they are located as follows 
  except as provided in Rule 43.3–D
  :
(1) Sidewalks, Parkways and Private Property: 12 inches
 (2)    Thoroughfares: 18 inches        
                
                         
                                     
D.    EXCEPTIONS
                           
                                                           
    
 (1)    Mechanical Protection:   Lesser depth than those listed in 
 Rule 43.3–C
   may be used where suitable  mechanical protection is employed. Suitable
 mechanical protection shall consist  of the following or their equivalents:
                                                                     
        
a) Steel conduit or plastic pipe made of unplasticised polyvinyl chloride having the properties and dimensions specified in Type II, High Impact, Normal Chemical Resistance in United States Commercial Standard No. CS 207–60 with a minimum wall thickness of 0.15 inch, or
 b) 
               A layer of concrete at least  3 inches in thickness above the cable.
                                         
 (2)    Terminations,   Splices or Other Points of Access: Lesser depths 
than those listed in   Rule  43.3–C
   are permitted where cables and conductors rise for terminations  or splices
 or where access is otherwise required.
                                             
        
Note: Rules 43.3–C and D added March 9, 1988 by Resolution No. E–3076.