General Order 95
Section XI
Supply Lines or Communication Lines Crossing over Railroads
113.4
Communication
For crossing spans, the size of conductors not supported on messengers
shall be not less than No. 12 BWG galvanized steel, or No. 10 AWG hard–drawn
copper or copper covered steel, except that paired wire, of which each wire
has an ultimate strength of not less than 170 pounds, may be used without
supporting messenger in spans which do not exceed 100 feet in Heavy Loading
Districts or 150 feet in Light Loading Districts.