Change List for this Rule


General Order 95


Section IV


Strength Requirements for All Classes of Lines


43.1       Heavy Loading

Heavy loading shall apply in all parts of the State of California where the elevation exceeds 3000 feet above sea level (see Appendix A for map indicating the approximate location of the heavy loading district). This loading shall be taken as the resultant stress due to wind, ice and dead weight under the following conditions:


A.      Wind

A horizontal wind pressure of 6 pounds per square foot of projected area on cylindrical surfaces, and 10 pounds per square foot on flat surfaces shall be assumed. Where latticed structures are used, the actual exposed area of one lateral face shall be increased by 50% to allow for pressure on the opposite face, provided this computation does not indicate a greater pressure than would occur on a solid structure of the same outside dimensions, under which conditions the latter shall be taken.


B.      Ice

A radial thickness of one–half inches of ice, weighing 57 pounds per cubic foot, on all conductors shall be assumed in computing vertical and wind loadings.


C.      Temperature

Conductor temperature shall be assumed to be 0°F at the time of maximum loading.  A conductor temperature of at least 130°F shall also be assumed for computing sag and its effect on structural loads due to weight span.


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