Original General Order 95

Section IV

Strength Requirements for All Classes of Lines

49.1      Poles, Towers and Other Structures

A.       Strength

Wood poles shall be of sound timber, free from defects which would materially reduce their strength or durability and they shall have sufficient strength to withstand, with safety factors not less than those specified in Rule 44, the maximum stresses to which they are subjected under the loading conditions specified in Rule 43.  The modulus of rupture used in calculation of safety factors shall be not greater than the value given in Rule 48.1.

Steel and reinforced concrete poles, together with their foundations, shall be of such material and dimensions as to withstand, with safety factors not less than those specified in Rule 44, the maximum stresses to which they are subjected under the loading conditions specified in Rule 43.  The fiber stress values used in calculation of safety factors shall be as specified in Rule 48.2 and 48.3.

Certain poles subject to special stresses due to angles in the line, dead –ending of conductors or other attachments, which stresses must be included in computing the loading and safety factor.  Poles subject to these special stresses sometimes require the use of guy attachment shall be considered merely as a strut, the guy taking all lateral stresses.  In such cases the pole strength requirement shall apply at the point of guy attachment rather than at the ground line.

Spliced or stub reinforced poles or pole top extensions, including the attachment (joint) of the different members involved, shall meet all of the vertical, transverse and longitudinal strength requirements of these rules as if a whole pole were used.  Spliced or stub reinforced poles or pole top extensions shall not be used where Grade “A” construction is required in supports of crossings or conflicts, or where Grade “B” construction is required for Class C lines crossing the main lines of major railways.

B.       Dimensions

The minimum top circumference of wood poles shall be not less than the following:

Note       Poles having a ground line circumference of less than 12 inches are not safe to climb unless supported by guys, pike poles etc.

*        Supply Poles in Grade “B” construction in rural, light loading districts may have a top circumference less than 19 inches but not less than 16 inches.

*        Communication Poles in Grade “B” construction at crossings over major railroads may have to circumferences less than 19 inches but not less than the following, provided such poles meet the specifications of the American Standards Association, 05.21941, 05.41941 or 05.61941, and are butt treated if of western red cedar or are fulllength pressure treated if of Douglas fir or southern yellow pine:

C.       Setting of Wood Poles

The depths of pole settings are given in Table 6 are applicable to wood poles set in firm soil or in solid rock.  Where the soil is not firm deeper settings or special methods of pole setting should be resorted to.  Where unguyed poles are set subject to heavy strains, or at corners or curves, a greater depth should be used.  Guyed poles may be set not more than one foot less than the depths specified in Table 6 provided the guys do not assume any normal working load under conditions of no wind and the resulting depths of settings are not less than 3 feet.

For communication lines, sawed poles of a cross section of 36 square inches or less may not be set to a depth of 6 inches less than the specifications shown in the following Table.

D.       Gains

Gains or equivalent means shall be provided for increasing surface contact of crossarms with round wood poles.  Where gains are cut, the depth shall be not less than onehalf inch more than one inch. “Slab” gains, metal gains, pole bands, or assemblies of wood or metal supports that provide suitable surface contact and adequate strength are permitted.

E.       Replacements (see Rule 44.2)