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 set flush with the plaster. It is
easily installed in a house being built, but requires much tearing
down of plaster for an old house. Since its expense prohibits it in
the average farm house, this system will not be described in detail
here.
(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.
[Illustration: 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.
[Illustration: Porcelain cut-out and plug fuse]
The mains, leading from the entrance switch, as shown in the diagram,
to the panel board, should be of the same size as the transmission
wire itself, and rubber-covered. These mains terminate at the
distributing board. They are connected to the terminals of the
cut-outs by means of heavy brass screws.
_Wire Joints_
[Illustration: 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 ordinary soldering salts. There are several
compounds on the market, consisting of soft solder in powder form,
ready-mixed with flux. Coat the wire joint with this paste and apply
the flame of an alcohol lamp. The soldered joint is then covered with
rubber tape, and over this ordinary friction tape is wound on. A neat
joint should not be larger than the diameter of the wire before
insulation is removed.
_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, in two pieces. One
piece is merely a continuation of the moulding itself; and the other
is a cap to connect permanently to the end of the lamp or iron cord,
which may be snapped into place in a second. Since there are a great
many designs of separable current taps on the market, it is well to
select one design and stick to it throughout the house, so that any
device can be connected to any outlet.
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 point, insert the tubes so they project 3/4 inch on each
side, and fill up the ragged edge of the hole neatly with plaster.
[Illustration: The distributing panel]
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 passing from one slot to the
other by being enclosed in non-metallic flexible conduit, called
circular loom.
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.
[Illustration: Snap switch connections]
Places where chandeliers or wall bracket lamps are to be installed
permanently are fitted with wooden terminal blocks, which fit over
the moulding and flush with the plaster. These, after holes have been
bored in them for the wires, and the wires drawn through, should be
screwed firmly to the wall or ceiling, always choosing a joist or beam
for support. Then a crow's-foot, or tripod of iron, tapped and
threaded for iron pipe, is screwed to the terminal block. The iron
pipe of the chandelier or wall bracket is then screwed home in this
crow's-foot.
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 spliced to the two wires coming out of the chandelier or
wall bracket. This joint is then soldered and covered with tape, and
the shell of the chandelier is screwed into place, covering the joint.
[Illustration: Detail of wooden moulding]
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 switch, is, in effect, merely an
instrument, which opens or closes a circuit, it should be connected to
only one wire, which is cut to provide two ends for the screw
connections in the switch. When a moulding branch is run down from the
ceiling to some convenient spot for a snap switch (with which to turn
the lights of a room on or off), a porcelain "T" is not used. All that
is necessary to do is to loop the bottom wire of the circuit down
through the branch moulding, and connect it to the switch at a
terminal block, or porcelain base.
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 single hanging lamp may be
suspended from a fielding rosette, as shown in the cut, provided a
single knot is tied inside both the rosette and the lamp socket, to
make it secure. This makes a very cheap fixture. The rosette of
porcelain will cost 15 cents; the lamp socket 20 cents, and the lamp
cord suspending the lamp and carrying the current will cost 1-1/2
cents a foot; while a tin shade will cost another 15 cents.
[Illustration: 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 in many large cities, because of the
liability of careless workmanship. It should never be installed in
damp places, or out of sight. If the work is well done, the system
leaves nothing to be desired; and it has the additional advantage of
being cheap, and easily done by any farmer who can use carpenter
tools. Farmers with moulding machinery can make their own moulding.
The code prescribes it shall be of straight-grained wood; that the
raceways for the wires shall be separated by a tongue of wood one-half
inch wide; and that the backing shall be at least 3/8 inch thick. It
must be covered, inside and out, with at least two coats of
moisture-repellant paint. It can be had ready-made for about 2 cents a
foot.
_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 lamp circuits. The wire used can be determined by
referring to the table for carrying capacity, under the column headed
"rubber-covered." A stove or range drawing 40 amperes, would require a
No. 4 wire, in moulding. A good plan is to run the heating circuit
through the basement, attaching it to the rafters by means of
porcelain knobs. Branches can then be run up through the floor to
places where outlets are desired. Such a branch circuit should carry
fuses suitable to the allowed carrying capacity of the wire.
_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 2-1/2 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 places, and should be kept clear of dust
and litter, and protected from abrasion.
[Illustration: 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.