Electric Wiring; A Primer for the Use of Wiremen & Students

Electric Wiring; A Primer for the Use of Wiremen & Students

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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. 1902 edition. Excerpt: ...to those accustomed to electric lighting work. Except in the Andrews concentric system of wiring, earth contacts are carefully avoided in electric light work, both the lead and return being equally well insulated. For an electric bell service, however, it is allowable to dispense with the return wire and use the earth itself, provided a good attachment or good earth can be made at each end of the circuit. This can usually be secured by making use of the water-pipes or gas mains, care being taken to see that a thoroughly good joint is made to the bell or switch connection, and that the earth is on the mains side of any cistern or gas meter, as the object in view is to make a connection that shall have a permanently low resistance. It is inadvisable to use two different sets of pipes for earth connection in the same circuit, as thereby permanent currents may be set up, which will cause damage at the points of connection of the wires. In cases where no system of pipes can be used, an earth plate of sheet copper or lead is buried in a hole surrounded with broken coke, tightly packed, well watered, and then covered in. The situation chosen should be one that is permanently damp if possible. Batteries. The power for working electric bells is usually supplied from a battery of primary cells, and the type of cell commonly employed for the purpose is the Leclanche cell, or some modified form of it. This cell as usually made up consists of an outer glass vessel of a square shape, containing a solution of sal ammoniac in water, an amalgamated zinc rod provided with a terminal, and a cylindrical pot made of unglazed porcelain. Inside this pot is sealed a carbon plate with one end projecting, and carrying a terminal. The space round the plate inside the pot...show more

Product details

  • Paperback | 50 pages
  • 189 x 246 x 3mm | 109g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236494571
  • 9781236494573