WIRING THE HOUSE The insurance code—Different kinds of wiring described—Wooden moulding cheap and effective—The distributing panel—Branch circuits—Protecting the circuits—The use of porcelain tubes and other insulating devices—Putting up chandeliers and wall brackets—"Multiple" connections—How to connect a wall switch—Special wiring required for heat and power circuits—Knob and cleat wiring, its advantages and drawbacks. The task of wiring your house is a simple one, with well-defined rules prescribed by your insurance company. Electricity, properly installed, is much safer than oil lamps—so much so indeed that insurance companies are ready to quote especial rates. But they require that the wiring be done in accordance with rules laid down by their experts, who form a powerful organization known as the National Board of Fire Underwriters. Ask your insurance agent for a copy of the code rules. Danger of fire from an electric current comes from the "short circuit," partial or complete; and it is against this danger that the rules guard one. The amount of electricity flowing through a short circuit is limited only by the fuse protecting that line; and since there is no substance known that can withstand the heat of the electric arc, short circuits must be guarded against. Happily the current is so easily controlled that the fire hazard is eliminated entirely—something which cannot be done with oil lamps. In house-wiring for farm plants, the wire should be rubber-covered, and not smaller than No. 14 B. & S. gauge. This is the wire to use on all lamp circuits. It costs about $0.85 cents per 100 feet. There are four kinds of wiring permitted, under the insurance code: (1) Flexible armoured cable: This consists of two-wire cable, protected with a covering of flexible steel. It is installed out of sight between the walls, and provides suitable outlets for lamps, etc., by means of metal boxes (2) Rigid and flexible conduit: As the name implies this system consists of iron pipe, in connection with flexible conduit, run between the walls. It differs from the above system, in that the pipes with their fittings and outlet boxes are installed first, and the wires are then "fished" through them. Duplex wires—the two wires of the circuit woven in one braid—are used; and a liberal amount of soapstone, and occasionally kerosene, are used to make the wires slip easily into place. This is the most expensive system, and the best; but it is difficult to install it in an old house without tearing down a good deal of plaster. It has the advantage of being absolutely waterproof and fireproof. (3) Wooden moulding: This is simply moulding, providing two raceways for the insulated wires to run in, and covered with a capping. It is nailed or screwed firmly to the wall, on top of the plaster; and when the wires have been installed in their respective slots and the capping tacked on, the moulding is given a coat of paint to make it in harmony with the other moulding in the room. This system is cheap, safe, and easily installed, and will be described in detail here. Detail of wooden moulding (4) Open wiring: In open wiring, the wires are stretched from one support to another (such as beams) and held by means of porcelain cleats, or knobs. It is the simplest to install; but it has the objection of leaving the wires unprotected, and is ugly. It is very satisfactory in barns or out-buildings however. The Distributing Panel The first point to consider in wiring a house with wooden moulding is the distribution board. It should be located centrally, on the wall near the ceiling, so as to be out of ordinary reach. It consists of a panel of wood—though fireproof material is better—firmly screwed to the wall, and containing in a row, the porcelain cut-outs, as shown in the cut, from which the various branch circuits are to be led. Each cut-out provides for two branch circuits; and each branch contains receptacles for two plug fuses. These fuses should be of 6 amperes each. The Insurance Code limits the amount of electricity that may be drawn on any branch lamp circuit to 660 watts; and these fuses protect the circuit from drafts beyond this amount. Porcelain cut-out and plug fuse The mains, leading from the entrance switch, as shown in the diagram, to the panel Wire Joints Examples of cleat and knob wiring, 1, 2, 3; wire joints, 4; flexible armoured conductor, 5 The branch circuits are, as has been said, of No. 14 rubber-covered wire, running concealed in wooden moulding. All joints or splices in this wire are made, as shown in the illustration, by first scraping the wires bright, and fastening them stoutly together. This joint is then soldered, to make the connection electrically perfect. Soft solder is used, with Branch Circuits First, make a diagram of your rooms and indicate where you wish lamps, or outlets for other purposes. Since wooden moulding can be run across ceilings, and up or down walls, lamps may be located in places where they are out of the way. In planning the circuit, remember that you will want many outlets in handy places on the walls, from which portable cords will convey current to table lamps, to electric irons and toasters and other handy devices which can be used on the lamp circuit. These outlets are made of porcelain, The code permits 660 watts on each circuit. This would allow 12 lamps of 55 watts each. It is well to limit any one circuit to 6 lamps; this will give leeway for the use of small stoves, irons, toasters, etc. without overloading the circuit and causing a fuse to blow. Having installed your distributing board, with its cut-outs, figure out the course of your first branch circuit. Let us say it will provide lights and outlets for the dining room and living room. It will be necessary to run the wires through the partitions or floors in several places. For this purpose porcelain tubes should be used, costing one to three cents each. Knock holes in the plaster at the determined When all the tubes have been set in place, begin laying the moulding. Run it in a straight line, on the wall against the ceiling wherever possible, mitering the joints neatly. Whenever it is necessary to change the run from the ceiling to the wall and a miter cannot be made, the wires should be protected in In running wooden moulding, avoid brick walls liable to sweat or draw dampness; keep away from places where the heat of a stove might destroy the rubber insulation of the wires; do not pass nearer than six inches to water pipes when possible—and when it is necessary to pass nearer than this, the wooden moulding should pass above the pipe, not below it, with at least an inch of air space intervening, thus avoiding dampness from sweating of pipes. Snap switch connections Places where chandeliers or wall bracket lamps are to be installed permanently are fitted with wooden terminal blocks, which fit Do not begin stringing wires until all the moulding of the circuit has been laid. Then thread the wires through the wall or floor tubes and lay them in their respective slots. If trouble be found making them stay in place before the capping is put on, small tacks may be driven into the moulding beside them to hold them. When a terminal block is reached, a loop is made of each wire, through the hole cut in the block, if the circuit is to continue in the same direction. If it is to end there, the two wires are drawn through taut, and cut off at a length of 5 or 6 inches. These end wires, or loops, are then scraped bare and If the moulding is run along the walls flush with the ceiling, as is usual, a branch is made for a wall light, or wall tap, by means of a porcelain "T," or branch-block, which provides the means for running the circuit at right angles to itself without letting the wires come in contact with each other where they cross. Separable current taps should be installed in handy places on all circuits, so that small heating devices may be used without removing the lamps from their sockets. The two wires are bared for half an inch where they run through these current taps, and are fastened by means of brass screws. "Multiple" Connections All electric devices for this installation—lamps, irons, vacuum cleaners, motors—must be connected across the circuit—that is, bridged, from one wire to the other. This is called multiple, or shunt connection. There is only one exception to it, in wiring the house. That one exception is installing a wall switch, the ordinary snap switch. Since this wall In wiring lamp fixtures, No. 14 rubber-covered wire will usually prove too large. For this purpose, No. 18 may be used, with one lamp to each loop. Hanging lamps may not be supported by electric lamp cord itself, if there is more than one lamp in the cluster, because the weight is apt to break the electrical connections. In such a case, the lamp should be supported by a chain, and the twisted cord conveying current to the electric bulbs, is woven in the links of the chain. For the pantry, kitchen, woodshed, barn, etc., a Detail of simple hanging lamp supported by rosette Official Inspection In all communities, your insurance agent must inspect and pass your wiring before you are permitted to throw the main switch and turn on the electricity. Frequently they require that the moulding be left uncapped, until they have inspected it. If you have more than 660 watts in lamps to a circuit; if your joints are not soldered and well taped; if the moulding is used in any concealed or damp place, the agent is liable to condemn your work and refuse permission to turn on the electricity. However the rules are so clearly defined that it is difficult to go wrong; and a farmer who does his own wiring and takes pride in its appearance is more apt to be right than a professional electrician who is careless at his task. After the work has been passed, tack on the moulding capping, with brads, and paint the moulding to match the woodwork. Wooden moulding wiring is perfectly satisfactory if properly installed. It is forbidden Special Heating Circuits If one plans using electricity for heavy-duty stoves, such as ranges and radiators, it is necessary to install a separate heating circuit. This is the best procedure in any event, even when the devices are all small and suited to Knob and Cleat Wiring Knob and cleat wiring, such as is used extensively for barns and out-buildings, requires little explanation. The wires should not be closer than 2½ inches in open places, and a wider space is better. The wires should be drawn taut, and supported by cleats or knobs at least every four feet. In case of branch circuits, one wire must be protected from the other it passes by means of a porcelain tube. It should never be used in damp Knob and cleat wiring Knob and tube wiring is frequently used in houses, being concealed between walls or flooring. In this case, the separate wires are stretched on adjoining beams or rafters, and porcelain tubes are used, in passing through cross beams. For a ceiling or wall outlet, a spliced branch is passed through the plaster by means of porcelain tubes or flexible loom. Wires from the house to the barn should be uniform with transmission wires. At the point of entry to buildings they must be at least six inches apart, and must take the form of the "drop loop" as shown in the illustration. A double-pole entrance switch must be provided, opening downward, with a double-pole fuse. In passing over buildings wires must not come closer than 7 feet to flat roofs, or one foot to a ridge roof. Feed-wires for electric motors should be determined from the table of safe carrying capacities, and should be of liberal size. |