Standard handbook for electrical engineers

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1918 Excerpt: ... The use of poles over 40 ft. long is to be avoided wherever possible, on account of the cost, the increased danger in storms and the difficulty of handling transformers and service connections. 169. Poles should be spaced in approximately equal span lengths of about 100 ft. to 125 ft., to keep the sag within safe limits ana to provide a sufficient number of points at which service drops may be taken off. The spans near self-supporting corner poles should be about 75 ft. long in order to relieve the strain on the corner pole. The poles should be placed opposite lot-lines to avoid interference with the rights of abutting-property owners. 170. Shaving and painting. It is considered good policy to carefully shave all poles, trim the knots, and give them two coats of paint. t A dark green color is very commonly used because of its harmony with foliage in residence districts. Fowle, F. F. "A Study of Sleet Loads and Wind Velocities;" Electrical World, Vol. LVT, 1910, p. 995. t Buck, H. W. "The Use of Aluminum as an Electrical Conductor;" Trans. International Electrical Congress, St. Louis, 1904. 171. Stepping. Transformer poles and others which are climbed at frequent intervals should be provided with pole steps. It is the practice in many of the large city systems to provide steps on all poles. 178. Gaining. The gains should be cut for the cross-arms before the poles are erected. The distance between cross-arm centres must be sufficient to give clearance for service drops and allow a safe working space for linemen. The space usually allowed is about 24 in. 173. Pole setting. Experience has proven that the following practice is conservative, as regards the depth of setting. Corner poles should be set about 6 in. deeper than the above. In rock...