go 95 appendix c-a

General Order 95

Appendix C

Conductor Sags

(a) Basis of Sag Curves for Supply Conductors

Data are presented in Appendix C in the form of curves in Charts numbers 1 to 9 inclusive, showing conductor sags which produce tensions that do not exceed either 35% of ultimate strength of the conductor at 60° F. and no wind, or 50% of ultimate strength (safety factor of 2) of the conductor under the maximum loading conditions specified for Light or Heavy Loadings in Rule 43 . These sags are considered particularly applicable to the stringing of new wire (i.e., they should be considered initial sags for conductors which have not been prestressed) and are not recommended in the case of used or so–called prestressed wire.

The curves of the sag charts were drawn from computations made under the following conditions:

1.	Sag curves in the Light Loading charts are based on 35% of conductor ultimate tensions at 60° F. and no wind.
2.	Sag curves in the Heavy Loading charts show sags which will obtain at 60° F. and no wind, in conductors which are so strung that under heavy loading conditions the conductor tension will be one–half of the ultimate tension.
3.	The sag curves for weatherproof wire are for conductors having a triple–braid–weatherproof covering.
4.	Conductor dimensions, weights and loadings were taken from the tables in Appendix B.
5.	Modulus of Elasticity–lbs. per square inch
	Copper---------------------------------------------------------------------------------------------------------------------	17,000,000
	Steel and iron, solid------------------------------------------------------------------------------------------------------	29.000,000
	Steel, stranded------------------------------------------------------------------------------------------------------------	21,000,000
	Copper–covered steel, solid----------------------------------------------------------------------------------------------	24,000,000
	Copper–covered steel, stranded----------------------------------------------------------------------------------------	23,000,000
6.	Coefficient of Linear Thermal Expansion – per degree F.
	Copper-------------------------------------------------------------------------------------------------------------------	0.0000094
	Steel and iron-----------------------------------------------------------------------------------------------------------	0.0000065
	Copper–covered steel-------------------------------------------------------------------------------------------------	0.0000072