Hawkins electrical guide. Questions, answers & illustrations; a progressive course of study for engineers, electricians, students and those desiring to acquire a working knowledge of electricity and its applications; a practical treatise (1914)
Hawkins, N. (Nehemiah), 1833- · New York, T. Audel · leaf 153
rubber, or of bitumen, and a metal sheath orcovering, usually of lead, is provided to protect the cable from UNDERGROUND WIRING 841 mechanical or chemical injuries. The non-moisture proof cablesare insulated with paper impregnated with oil, wax, or resinouscompounds. Metal Sheaths on Underground… … ?iG. 988.—Cross section of Edison main tube. A number of these tubes, which radiatefrom the center of distribution and loop the ends of the feeders together, have three con-ductors of the same size. These tubes are placed n the ground so as to bring the positiveand negative conductors on one side…
Electrical engineering
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