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<br />. <br />! <br /> <br />r <br />I, <br /> <br />r <br />I <br />l <br /> <br />.' A.. _ <br />~<Jl./} <br /> <br />" <br />, !4& <br /> <br />TRANSMISSION LINES <br /> <br />I-beam seCtion. The cross section of copper is 510,000 circular <br />mils; the over-all diameter 1.004 inches; and the' weight 1.62 <br />pounds per linear foot. <br />The aluminum conductor is supported by stdngs of thirteen <br />lO-inch insulators having a mechanical strength of 15,000 pounds. <br />The cable is protectcd at the suspension clamps by armor rods and <br />suitable vibration dampeners are provided. For the copper con- <br />ductor in the alkali section of the line 17 units of insulators are <br />used to make up for the impaired insulation value of the discs <br />when coated with alkali dust. In this section, also, special towers <br />were used to accommodate these longer strings of insulators. <br />Vibration dampeners were not specified for the copper conduc- <br />tor but tests made on the completed line showed sufficient vibration <br />to warrant their installation. Consequently, dampeners identical <br />with those used on the aluminum except for copper contact sur- <br />faces, were installed by District crews, <br /> <br />Surveys <br />The first survey work in connection with the transmission lines <br />was accomplished in the spring of 1931, to secure sufficient data for <br />the design of the principal elements of the line and the preparation <br />of preliminary estimates. <br />In September 1933 the survey of the final line was started. In <br />the rugged Whipple Mountain area northwest from Division No.1 <br />and the Gene plant an aerial reconnaissance was made, followed by <br />sufficient aerial photography to provide complete coverage of pos- <br />sible locations. This not only proved of great value in locating the <br />patrol road' and transmission line through this difficult area but <br />also revealed a desirable relocation of Intake pumping plant which <br />resulted in considerable savings in cost. <br />By the end of May 1934, the entire 237 miles of final location had <br />been chained, profiled, and tied into U. S, Land Office corners, <br />Profiles were taken on the center line and 25 feet to right and left <br />while additional "shots" were taken at points of questionable <br />clearance, Field books were submitted to the Banning office where <br />profiles were prepared and forwarded to the Los Angeles office for <br />the spotting of towers. <br /> <br />Roads <br />Since roads were lacking over a large part of the line, a District <br />road crew was organized as soon as possible after the final location <br />