go 128 appendix a table 1

General Order 128

Appendix A

Summary of Dimensions, Clearances, and Depth Requirements

Table 1 Clearance and Depth Requirements for Supply and Communication Systems

Case No.	Nature of Clearance or Depth	Requirements �	Reference Rules
Clearances
1	Clearances Cables when independently installed *	3� concrete, 4� brick, or 12� earth	33.4-A(1)(a) , 33.4-A(2)(a) , 43.3-A
2	Cables when concurrently installed *	No separation required when parties mutually agree For random separation, see Rule 43.3-B(1)	33.4-A(1)(b) , 33.4-A(2)(b) , 43.3-B
3	Cables and Ducts From Foreign Structures(Except Supply or Communication Systems) when independently installed	12� when paralleling and 6� when crossing	31.4-A(1) , 33.4-A(3)(a), 41.4-A(1) , 43.3-A
4	Cables and Ducts From Foreign Substructures(Except Supply or Communication Systems) when concurrently installed	No separation required when parties mutually agreeFor random separation, see Rule 43.3-B	31.4-A(2) , 33.4-A(3)(b) , 41.4-A(2) , 43.3-B
5	Separation of Communication and Supply duct systems independently installed	3� concrete, 4� brick or 12� earth	31.4-B(1) , 41.4-B(1)
6	Separation of Communication and Supply duct systems concurrently installed	No separation required when parties mutually agree and both systems are in rigid ducts	31.4-B(2) , 41.4-B(2)
Depth
7	DepthDepth of Cables and Ducts Under Railroads	30� below street railroads,42� below other railroad	31.4-C(1) , 33.4-B , 41.4-C(1) , 43.3
8	Depths of Supply Cables and Ducts	0 - 750 Volts: 24� below Thoroughfares 18� elsewhere (Sidewalks, Parkways and Private Property) 751 - 35,000 Volts: 24� Above 35,000 Volts: 36�	31.4-C , 33.4-C , 33.4-D
9	Depths of Communication Cables and Ducts	18� below Thoroughfares, 12� elsewhere (Sidewalks, Parkways and Private Property)	41.4-C , 43.3

* For definitions of independently and concurrently installed, see Rules 20.5 and 21.8 .

� Clearances and depths shown may be reduced under certain conditions - see referenced rules. For measurement of clearance, see Rule 17.9 .