General Order 64
Section V
General Strength Requirements For All Classes Of Supply Lines
51
Required Grades Of Construction.
Supply
lines shall have construction designated as Grade “A,” Grade “B,” Grade “C,” as
specified below, according to the conditions involved, these representing
different strengths of construction.
(see Table 3, and Table 5 for safety factors and
conductor sizes, to be used with the different grades of construction.
(a) Supply lines over Class “S” lines at crossings, conflicts, or on common poles, shall conform to the following grades of construction: (See Definition 17(d) and Section III.)
CLASS “H” LINES.
With important Class “S” lines Grade “A”
With other Class “S” lines Grade “B”
CLASS “L” LINES.
(b) Supply lines crossing over railways operated by steam, electricity or other motive power shall conform to the following construction requirements in both urban and rural districts. (See Definition 17(t).)
Important railways Grade “A”
Unimportant railways Grade “B”
Supply lines crossing over street railways (see Definition 17(u)) which are on traveled portions of highways need not be given the grades of construction specified above for railway crossings. The grade of construction to be used fro the supply line under these conditions will be determined by the voltage class of the wires concerned, including the trolley contact wire classed as an ordinary supply line.
(c) All Class “H” supply line except as required to be Grade “A” shall conform to Grade “B” requirements.
(d) All Class “L” supply line shall conform to Grade “C” requirements when not required to be Grade “A” or Grade “B”.
(e) In cases where two or more of the conditions above listed exist, the grade of construction shall be the highest called for under any condition applying.
(f) Where a line crosses in one span over two other lines, the grade of construction shall be not less than would be required if either of the two lower lines crossed the other.
(g) Where lines of different voltage cross each other, or are in conflict, or are on the same poles or towers, the higher voltage line shall, if conditions permit, be carried at the higher level. (See Rule 41.)