Cyclopedia of applied electricity : a general reference work on direct-current generators and motors, storage batteries, electrochemistry, welding, electric wiring, meters, electric lighting, electric railways, power stations, switchboards, power transmission, alternating-current machinery, telegraphy, etc. . Fig. 47. Single- and Multiple-Duct Tile Conduits Manholes. For all drawing-in systems, it is necessary to pro-vide some means of making connections between the several lengthsof cable after they are drawn in, as well as for attaching the cables cannot be handled in lengths g
Cyclopedia of applied electricity : a general reference work on direct-current generators and motors, storage batteries, electrochemistry, welding, electric wiring, meters, electric lighting, electric railways, power stations, switchboards, power transmission, alternating-current machinery, telegraphy, etc. . Fig. 47. Single- and Multiple-Duct Tile Conduits Manholes. For all drawing-in systems, it is necessary to pro-vide some means of making connections between the several lengthsof cable after they are drawn in, as well as for attaching the cables cannot be handled in lengths greater than about500 feet, and less than this in many cases, vaults or junction boxesmust be placed at frequent intervals. Such vaults are known assplicing vaults or manholes. The size of the manhole depends uponthe number of ducts in the system, as well as on the depth of theconduit. If the ducts be laid but a short distance from the surfaceof the street and traffic is light, the cables may readily be spliced with 88 POWER TRANSMISSION 79 a manhole but 4 feet square and 4 feet deep. The smaller vaultsare often called handholes. Deeper vaults are from 5 to 6 feet square,and the jBoor should be at least 18 inches below the lowest ductson account of convenience to the workmen and to serve as collect-ing
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Keywords: ., bookauthoramericantechnicalsoci, bookcentury1900, bookdecade1910
