General Order 64-A
Strength Requirements For All Classes Of Lines
47.5 End Supports in Grades “A” or “B”
In Grades “A” or “B” construction the longitudinal stress on the end supports of crossings, conflicts or joint use, where located in lines of the same grade of construction, shall be taken as the unbalanced tension equal to the stress of one-third of the total number of conductors (not including overhead ground wires), such one-third of the conductors being so selected as to produce the maximum stress in the supports. If the application of the above results in fractional part of a conductor, the nearest whole number shall be used. The construction of the supports (including poles, structures, towers, crossarms, pins, insulators and conductor fastenings) shall be such as to withstand at all times the stress specified with a safety factor at least equal to unity. Excluded from this rule are crossings, conflicts, or joint use construction involving Class L circuits, street railways and conductor fastenings of Class C circuits, where Grade “B” construction is involved.