General Order 95

Strength Requirements for All Classes of Lines

49.7     Messengers and Span Wires

A.      Material

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

B.      Strength

Messengers and span wires shall be capable of withstanding, with safety factors as specified in Rule 44 , the tension developed because of the load they support combined with the loading conditions specified in Rule 43 . An allowance of 300 lbs. of vertical load for a worker and cable chair shall be made in computing tensions in messengers and span wires which support cables except in the case of short spans which are not required to support workers or where the ice loading specified in Rule 43.1–B would exceed the allowance for the worker and cable chair.

Guys supporting messenger loads shall comply with the safety factors specified in Rule 44.

Note:      Revised February 5, 2014 by Decision No. 14-02-015. 

C.      Supports

Messengers supporting cables shall be attached to poles or crossarms with hardware that complies with the safety factors specified in Rule 44 , based on the weight of the messenger wire, cable, line-mounted equipment plus an allowance of 300 lbs. for a worker and cable chair. If in heavy loading areas the specified ice load exceeds in weight the 300 lbs. allowance, such ice load shall be used in making the calculations in preference to the weight of the worker and cable chair.

Note:      Revised February 5, 2014 by Decision No. 14-02-015. 

D.      Replacements (See Rule 44.3 )