50 



METHODS OF COMMUNICATION FOR FOREST PROTECTION 



2 SPACING 



On straight sections poles should be set 176 ft. apart, which is equivalent to 30 

 poles per mile. For a grounded line, carried on poles, the distance apart, under 

 favourable conditions, may be 200 ft., or about 26 poles to the mile. Changes in 

 the direction of a line should be made gradually by spreading the curve over as 

 many poles as possible, raking each pole outward to offset the strain. On curves and 

 corners where the pull is from 10 to 30 ft., the pole spacing should be reduced to 

 100 ft. Where the pull js more than 30 ft., the turn will be made on two poles, 

 approximately 100 ft. apart, with equal spacings in the adjacent spans on either side. 

 At right-angled corners the length' of the section on either side next to the corner 

 pole should not exceed 100 ft. 



Where it is necessary to make a span of from 200 to 300 ft., the adjacent sections' 

 should be 100 ft. in length. Spans of from 300 to 500 ft. should have two sections 

 of 100 ft: on each end. For spans of more than 500' ft. special construction is 

 required. 



Where the line crosses solid rock, the length of spans may be increased v,p to 

 300 ft. to avoid the expense of blasting holes. When it is necessary to blast many 

 holes, special construction may be d'esirable, and the matter should be taken up with 

 the district inspector. 



Abrupt changes in the level of the wire should be avoided. Poles 1 shoald be 

 set on either side of a high or low point, using long poles, if necessary, to obtain 

 the desired clearance in the span. In crossing a ridge or ravine, for example, it is 

 better to space the poles so that one is set on each side of the ridge or ravine rather 

 than to set a pole on the crest or in the bottom. 



3 DIGGING HOLES 



On straight sections holes should be vertical, uniform in siz<e from top to bottom, 

 and at least 6 inches larger in diameter than the butt of the pole. This will permit 

 the earth to be evenly tamped around the pole for the total depth of the hole. In 

 general, the depth of holes for various sizes of poles should be that shown in the 

 following table. On curves or in soft soils, however, holes should be at least 6 inches 

 deeper than the figures given. 



TABLE B SIZE OF HOLE FOR DIFFERENT LENGTHS OF POLE 



On a hillside the depth of a hole should be measured from the lowest side of 

 the opening. Where the hillside is so soft that the pole may possibly " kick out," 

 the depth of the hole should be determined by the foreman. 



Where it is not possible to dig the required depth, the hole should be blasted. 

 If this is not feasible, the pole should be securely braced or guyed. 



4 ATTACHMENTS TO POLES 



Standard brackets with insulators and all other equipment which is to be 

 Attached to the pole should be put in place before the pole is erected. 



