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General Order 64-A


Section IV


Strength Requirements For All Classes Of Lines


49.7    Messengers and Span Wires


A.    Material

Messengers shall be stranded and of galvanized steel, copper-covered steel or other corrosion-resisting material not subject to rapid deterioration.


B.    Strength

The minimum strength of cable and suspension messengers shall not be less than that given in the following table:


Table 8

Weight of conductor cable in pounds per foot

Messengers (ultimate tensile strength)

Messengers (safe working tension)

Less than 2.25 lbs.



2.25 lbs to 5 lbs.



Over 5 and less than 8 lbs.




This does not apply to messengers supporting short spans of cable which are not required to support workmen such as the drops from the line poles to cable terminal.


The above requirements may be deviated from in special cases for cables in excess of 8 lbs. per foot, provided, under the maximum loading conditions, the tension in the messenger shall not exceed the safe working tensions given above.


The strength of the guy strand shall be such that the safety factor required of the messenger (see Table No. 8), is not exceeded.  It is recommended that overhead guys shall be the same size as the suspension strand and that anchor guys shall be enough larger than the suspension strand to compensate for the angle between the plane of the horizontal stress of the suspension strand and the line of the guy.


C.    Supports

Messengers supporting cables shall be attached to poles or crossarms with hardware which provides safety factors at least equal to those specified in Table 4, , based on the weight of the cable plus an allowance of 200 lbs. for the man and cable chair.  If in heavy loading areas the specified ice loads exceeds in weight the 200 lbs. allowance, such ice load shall be used in making the calculations in preference to the weight of the man and cable chair.  All hardware subject to injurious corrosion shall be protected by galvanizing, painting or other suitable treatment.


D.    Replacements (see Rule 44.2)