Overhead transmission lines and distributing circuits; their design and construction

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. 1915 Excerpt: ...forward and both are carried once more round the insulator and line wire, crossing the starting point and finishing off with six or eight twists round the line wire on both sides of the insulator (Fig. 130). Another method of tying a line into the top groove is shown in Fig. 140. This is the method used on the 60,000-volt line of the Ontario Power Company. The long twisted portions are here intended to add to the section of the conductor (aluminium) so as to delay its melting through in case an arc should occur. Still another arrangement is shown in Fig. 141, where the binding wire is replaced by terminal clamps and the line is protected by a metal sheath slipped over it. Figs. 142 and 143 show a terminal clamp arrangement suitable for cases in which the line wire slants relatively to the insulator owing to considerable differences in level between the supporting points. The odd bits of wire cut off during binding operations must be carefully collected as they form a serious danger to cattle by becoming mixed with their fodder or by running into their feet. The longer pieces of wire also are favourite missiles for boys to sling over the line and are then liable to cause short circuits. In the case of suspension insulators the line wire is carried in a clamp cemented into the first member of the insulator chain as shown in Fig. 132. 13. JOINTS AND BRANCH CONNECTIONS ON THE LINE. In all cases in which the presence of a joint weakens the wire mechanically the branch wire must be relieved of all tension. The joint should, whenever possible, have the same strength as the wire, but, in any case, it should have a factor of safety of 2 considering the actual stress existing on the wire. The making of the joint must not weaken the main conductor, must not produce sh...