This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
All country houses, unless in very remote situations where there are no chances of an electric current ever being obtained, should be wired for electric lights. The usual method is the knob and tube system, where the wires, of copper heavily insulated, are run between beams and studs on porcelain knobs, and in short porcelain tubes where passing through timbers. (Fig. 35.) Although the insurance exchanges, employ inspectors and require that every job of wiring shall be reported to them and inspected by their men, it will be well for the superintendent to carefully watch this construction to see that all wires are thoroughly insulated and at least 3 inches apart to avoid any chance of contact, that they are not allowed to sag, and that the joints are properly protected by a free use of insulating tape. Upon brick or stone walls, and in all places where there is danger of injury, wires should be run in conduits or pipes. In this case the angles and bends of the conduits must be made in easy curves so that the wires may be easily "drawn in". All wiring should be tested when installed and again at completion of the building, to insure against any mechanical injury. For electric bells, it is usual to run an insulated wire secured to the studs by staples, and care must be taken to see that bells as well as light outlets are placed in convenient places. If the bells are to be operated mechanically the wires should be run in zinc tubes, but as such wires stretch and break in time, the electric wires are generally preferred.
Fig. 35. Electric Wiring.