FIGURE 169.
Another form of program board is shown in Figure 170. This requires much more wiring. Each lamp on the board is connected to a plug or switch at the operator’s station. Whichever switch is closed on the small board at the right causes a corresponding light on the large board to appear.
FIGURE 170.
Two program boards are usually installed, one at each side of the stage, facing the audience at angles, so that one can be seen from the extreme right, the other from the extreme left.
FIGURE 171.
A system that is often used for carriage call is shown in Figure 171. The lights are arranged on circuits as indicated by numbers. All lamps bearing the same number being connected to one wire leading to the controlling station. Thus there are eight controlling or switch wires and there is one wire common to all. A special switch is provided which has a contact point for each wire. Paper cards, perforated specially for the numbers they represent, are used. If a card bearing a certain number is inserted in the proper place and the switch closed, the number printed on the card will appear on the sign. If, for instance, the shaded circles in the card at the left of the figure allow contact to be made, the lights indicated by black circles will light up and make the figure “6”.
Another form of program or call board is shown in Figure 172. This requires more wires than the one just described, one wire being carried to the controlling board from each lamp. The connections may be made in various ways. Sometimes they are made with knife switches. If it is desired to make the figure 1, for instance, only the three lights in a vertical row in the center need be lighted, and to do this the three wires from those lamps must be connected to one switch. To make the figure 2, seven lamps would have to be lit by another switch. It is capable of making any letter or number and when used as a program board only may be somewhat simplified.
FIGURE 172.
In connection with these signs a large number of wires may be required and attention should be given to the following rule:
Except in the case of stage pockets the same conduit must never contain more than four two-wire, or three three-wire circuits of the same system except by special permission, and must never contain circuits of different systems.
Proscenium Side Lights.—These lights are located on each side of the stage, as near as possible to the edge of the proscenium opening and often in front of the steel curtain. They are of more use in musical productions, where choruses spread over the whole stage, than in dramatic productions where the interest is more in the center of the stage. In some theaters the proscenium side lights extend the full height of the opening and are arranged for three colors in the same manner as footlights and borders. Very often, however, only ten or twelve lights are arranged on each side of the stage.
The construction rules are the same as those governing foot-lights.
Lamps must be protected by strong wire mesh. This is essential as in many cases actors are very likely to back into them while passing off the stage. Portable strips are sometimes used as proscenium side lights.
Receptacles.—See “Stage Pockets”.
Retiring Rooms.—In these places a quiet subdued illumination is usually desired. There are also often quaint objects and effects to be illuminated. A large number of outlets conveniently located for the use of table lamps, fire places, and illumination of pictures, should be provided.
Rheostats.
Must be placed on a switchboard, or at a distance of at least one foot from combustible material, or separated therefrom by a slab or panel of non-combustible, non-absorptive, insulating material such as slate, soapstone, or marble, somewhat larger than the rheostat, which must be secured in position independently of the rheostat supports. Bolts for supporting the rheostat shall be countersunk at least one-eighth inch below the surface at the back of the slab and the bolt heads shall be covered with insulating material. For proper mechanical strength, slab should be of a thickness consistent with the size and weight of the rheostat, and in no case to be less than one-half inch.
If resistance devices are installed in rooms where dust or combustible flyings would be liable to accumulate on them, they must be equipped with dust-proof face plates.
Must be made entirely of non-combustible materials, except such minor parts as handles, magnet insulation, etc. All segments, lever arms, etc., must be mounted on non-combustible, non-absorptive, insulating material.
Clamps for connecting wires to the terminals must be so designed as to insure a thoroughly good connection and must be sufficiently strong and heavy to withstand hard usage. For currents above 30 amperes, lugs into which the connecting wires may be soldered, or approved solderless connectors must be used. Clamps or lugs will not be required when leads are provided as a part of the device.
Motor-starting rheostats must be so designed that the contact arm cannot be left on intermediate segments, and for direct-current circuits must be provided with an automatic device which will interrupt the supply circuit before the speed of the motor falls to less than one-third of its normal value. In motor-starting rheostats for alternating-current circuits the automatic interrupting device may be omitted.
Overload-release devices which are inoperative during the process of starting a motor will not be approved, unless other circuit-breakers or fuses are installed in connection with them.
Signals.—Signals are necessary between the manager’s office and the stage electrician’s station; for this purpose telephones are generally used. In many cities a fire-alarm signal system is also required and it is specified to what part of the house it shall lead. In addition to the above, a means of signalling the fly floor and the orchestra leader must be provided. Buzzers are used for these signals. It is best to use batteries for all these signals instead of attempting to run them from lighting circuits. Means of signalling the arc-lamp station in the gallery or the balcony should also be provided for use in connection with lantern slides, etc. Telephone connection to this point will also be very useful in order to give instructions to the lamp operator. Return-call systems are advisable in all places so that the electrician can be called from any point.
In some cities the local laws require these wires to be in conduit so as to preclude any possibility of their communicating fire to anything. At any rate the wires should be very carefully installed.
Signs.—In nearly all electric signs used about theaters the letters are outlined by incandescent lamps. Small candle-power lamps are always used. They are not only economical but much more attractive because the glare from too much light is very annoying. Many signs are equipped with low candle-power tungsten lamps wired in series. In order that the letters should show to full advantage they should be glossy white and be kept clean. Such letters will show as bright as the lamps. It is best to wire the sign so that either side can be used independent of the other. In many cases, also, signs are wired so that each letter is independent of the others for use with flashers.
Attraction signs are used to advertise the attractions which appear from time to time. Independent portable letters are used and changed as often as the attractions change. Each letter must be fitted with cable and attachment plug of some kind and should have a separate circuit. Cut-outs are generally located on the frame and must be protected from the weather.
Sockets.—Sockets must be of approved construction. Key sockets must not be used for emergency or exit lighting. Sockets with fiber linings must not be used unless protected by insulating joints. In damp places weatherproof sockets must be used. Where inflammable gases exist, lamps must be incased in vapor-proof globes. Porcelain sockets should not be used in theaters. Weatherproof sockets are generally used for portable purposes because they have no screws, etc., to work loose.
Stage Cable.—Stage cables are allowed in theaters only where flexible conductors are absolutely necessary. All wiring that can possibly be installed in conduit or strip construction should be so arranged. By the use of plugging boxes the quantity of stage cable necessary can be much reduced. Plugs for arc and incandescent lights must not be interchangeable.
Stage Flues.—In most cities stage flues, as described in the chapter on “Theater Buildings”, are required. The requirement is also, often, that they be released by electrical means. The rule below contemplates a circuit containing an electro-magnet and at least two switches in series. The magnet must be energized to hold the ventilator closed. If the current fails or a switch is opened the dampers must fly open at once. Where direct current is available the magnet is usually wound for 110 volts and connected to a circuit that is always alive. In case of an isolated plant which is shut down at night some arrangement for tying the dampers down should be made, but it is not always advisable, as once tied they are likely to remain so and sure to fail when needed. Magnets do not work well on alternating currents and in such cases the magnet should be wound for a small current to be obtained from a gravity battery which may be allowed to be always working. Locate the battery where it will not freeze.
In cases where dampers are released by an electric device, the electric circuit operating same must be normally closed. Magnet operating dampers must be wound to take full voltage of circuit by which it is supplied, using no resistance device, and must not heat more than normal for apparatus of similar construction. It must be located in loft above scenery, and be installed in a suitable iron box with a tight, self-closing door.
Such dampers must be controlled by at least two standard single-pole switches mounted within approved iron boxes provided with self-closing doors without lock or latch, and located, one at the electrician’s station and the others as designated.
Stage and Gallery Pockets.—Stage pockets are usually located on each side of the stage just far enough from the center to be safely back of the scenery. The more pockets there are the better it will be. Each pocket usually contains four circuits, and one of these at least should be for incandescent lights. It will be convenient if the stage pockets are divided into four groups, each group under control of a separate switch and the whole again under control of a main switch. This will enable the operator to throw off all of the pockets at once, if necessary, or to make any combination desired.
FIGURE 173.
Sometimes lights fed through stage pockets require to be dimmed; but it is hardly practicable to arrange dimmers for apparatus carried by traveling companies, since a dimmer must be selected with respect to the amperage it is to control.
In addition to the rules given below, some cities require the bottom of stage pockets to be open, so as to avoid an accumulation of dust. This is a very essential precaution, as otherwise the pockets soon fill up or require very frequent cleaning. The covers must be substantial as heavy trucks are sometimes run over them. Two illustrations of stage pockets are given in Figures 173 and 174. The plugs used with these boxes are shown in Figure 175.
FIGURE 174.
FIGURE 175.
Gallery pockets are not usually laid in the floor but along the railing. The gallery pockets should be under separate control from the stage switchboard.
Must be of approved type, insulated from ground and controlled from switchboard, each receptacle to be of not less than 35-ampere rating for arc lamps nor 15-ampere for incandescent lamps, and each receptacle to be wired to its full capacity. Arc pockets to be wired with wire not smaller than No. 6 B. & S. gauge and incandescent pockets with not less than No. 12 B. & S. gauge. Plugs for arcs and incandescent pockets must not be interchangeable.
Switches.—All knife switches should be enclosed in cabinets unless they are located on a switchboard. In exposed places, flush switches should be used. The usual height at which scattered switches are located is about four and one-half feet above floor. Door switches are of use principally in dressing rooms.
FIGURE 176.
Diagrams of three-way switches are given in Figures 176 and 177. In Figure 177, the wiring by which a light can be controlled from three different points is shown. The middle switch must be a pole-changing switch. In this case a throw-over knife switch is wired to perform this function. Omitting the knife switch we have two three-way switches controlling the light. When both switches (indicated by broken lines) connect to the same wire the light burns.
FIGURE 177.
In Figure 176, when both switches connect to the same polarity the light is out; when one of them is connected to the other pole the light burns. Under certain conditions this arrangement is more economical in wire but has the disadvantage which the other method avoids, of bringing both poles to each switch. This method cannot be used with direct-current arc lamps. Three-way switches are useful on stairways, enabling one to turn on a light at the bottom of the stairway and turn it off when at the top or vice versa.
Must be placed on all service wires, either overhead or underground, in the nearest readily accessible place to the point where the wires enter the building, and arranged to cut off the entire current. Departure from this rule may be authorized only under special permission in writing. Switches controlling emergency lighting must be located only in the lobby.
Must when used for service switches, indicate, on inspection, whether the current be “on” or “off”. Switch cabinets must be deep enough to allow the door to be closed when 30 ampere branch-circuit switches are in any position, and when larger single-throw switches are thrown open as far as their construction and installation will permit.
Must, for constant-current systems, close the main circuit and disconnect the branch wires when turned “off”; must be so constructed that they shall be automatic in action, not stopping between points when started, and must prevent an arc between the points under all circumstances. They must indicate whether the current be “on” or “off”. Service cut-out and switch must be arranged to cut off current from all devices including meters.
Must always be placed in dry, accessible places, and be grouped as far as possible. Single-throw knife switches must be so placed that gravity will not tend to close them. Double-throw knife switches may be mounted so that the throw will be either vertical or horizontal as preferred, but if the throw be vertical a locking device must be provided, so constructed as to insure the blades remaining in the open position when so set.
When practicable switches must be so wired that blades will be “dead” when the switch is open.
When switches are used in rooms where combustible flyings would be likely to accumulate around them, they must be enclosed in dust-tight cabinets.
Up to 250 volts and thirty amperes, approved indicating snap switches are suggested in preference to knife switches on lighting circuits.
Single-pole switches must never be used as service switches nor for the control of outdoor signs or circuits located in damp places, nor placed in the neutral wire of a three-wire system, except in the two-wire branch or tap circuit supplying not more than 660 watts.
Where flush switches or receptacles are used, whether with conduit systems or not, they must be enclosed in an approved box constructed of iron or steel, in addition to the porcelain enclosure of the switch or receptacle.
Hinges of knife switches must not be used to carry current unless they are equipped with spring washers, held by lock-nuts or pins, or their equivalent, so arranged that a firm and secure connection will be maintained at all positions of the switch blades.
Spring washers must be of sufficient strength to take up any wear in the hinge and maintain a good contact at all times.
Switches for currents of over thirty amperes must be equipped with lugs, firmly screwed or bolted to the switch, and into which the conducting wire shall be soldered. For the smaller sized switches simple clamps can be employed, provided they are heavy enough to stand considerable hard usage.
Where lugs are not provided, a rugged double-V groove clamp is advised. A set screw gives a contact at only one point, is more likely to become loosened, and is almost sure to cut into the wire. For the smaller sizes, a screw and washer connection with up-turned lugs on the switch terminal gives a satisfactory contact.
See “Panel Boards”.
Switchboards.—The stage switchboard is usually located on the right-hand side of the stage. This position enables the operator to watch cues easily and handle his switches with the right hand. This side is also the one from which the stage manager prefers to work. It is preferable to have the board raised high enough above stage level to allow all space on the stage to be used by actors. If the switchboard is located on stage level it takes up much room that is valuable and makes stage exits for actors difficult.
The wiring of a good switchboard should be divided into three parts, each part independent of the others, so that any one part can be entirely cut off without interfering with the other. All of the house lights should be fed through one main switch, and all of the stage light connected to another set of bus-bars, but it is best not to have the stage side of the board as a whole controlled by a main switch. If the stage side of the board is controlled by a single switch there exists the possibility that this switch may be used to cut off everything for a dark scene and when light is again wanted a part of the lighting of the previous setting may be left on and possibly interfere with the new scene.
FIGURE 178.
The stage lighting is usually divided into four groups, viz.: three color groups and a group of stage pockets. The number of white lights is usually equal to that of all of the colors.
Figure 178 shows a well laid out switchboard. All of the lights in the auditorium are controlled by switches shown in the upper right-hand corner and all of these are under the control of the main switch. The house lights are usually thrown on or off as a whole and this main switch must be convenient for the operator.
The stage pockets are controlled by the bank of switches shown at E. Lights burning off the stage pockets generally are controlled by special operators on the stage or by actors, and need not be so very convenient to the switchboard operator. They must, however, be under his control when necessary; but here also a main switch is not advisable.
In addition to the three groups of lights spoken of above, there are a number of lights which should be controlled from the switchboard but must be so connected that they will be left on, no matter what is done with either house or stage light.
In this group belong a few lights mounted at the top of the switchboard which enable the operator to see his switches when all else is dark. These lights are generally shielded so as to throw no light in the direction of the stage opening. The orchestra lights also belong in this group, but a special switch may, with advantage, be arranged on this circuit to bring it under the control of one of the musicians. In some dark scenes these lights are turned out for a short time, but it is very important that they be turned on again at the proper moment, and this is more certainly assured, by giving the musicians control, than by leaving it to an electrician on the stage who may be very busy with other matters at the time.
The lights on the fly floor and in the rigging loft, as well as those in dressing rooms and basement, must also be independent. Fan motor circuits should also be independent of the house circuit. They are often needed when the house lights are thrown off.
With the switchboard illustrated in Figure 178 we have shown only the switches governing the house and stage proper. The switches governing the other lights are usually worked into the vacant spaces between the two groups. Each switch should be labeled in such a manner that a new operator can learn the board easily.
The most important part of the board is that part governing the stage lighting, and this should always be placed as conveniently as possible to the operator. A stage switchboard is like a house in that no one is wholly satisfied with the one he has, but thinks he could improve it a little if he could build it over again. The arrangement shown in Figure 178 is, however, quite satisfactory for general purposes. The white lights predominate in the ratio of two to one and are laid out in two groups A and B. Both groups are controlled by the switch C. The switches A and B do not control the lights at all if the smaller throw-over switches at the right are thrown downward. A diagram of these switch connections is given in Figure 179 where the switches B and C are indicated. The object of the switches A and B is to help in quickly increasing or decreasing the illumination on the stage. If in the beginning of a certain scene, for instance, only a small quantity of light is wanted, while a little later full illumination is desired, the low illumination may be obtained by throwing the proper switches down; the additional illumination which will be needed a few minutes later may be prepared for by setting the other switches needed to the upward position and at the proper moment closing switch B; this will instantly produce the effect which otherwise would be possible only by operating a number of switches in succession. In the same way, by a reversal of this process, the illumination may be reduced in any amount. This feature is very valuable in many stage settings.
FIGURE 179.
To throw off all of the white lights the switch C must be opened. The switches D and F are main switches controlling colored lamps. All lamps of one color should be connected to one or the other of these groups unless some special color effect is desired.
From the three groups of switches, circuits extend into the foot lights, into every border, and into the proscenium side-light strips so that the color scheme may be carried out in any of these.
The handles of all switches in a row should be of the same height so that the operator may more readily accustom himself to catch them quickly. It is better to have switches of some excess capacity, as the heavy metal stands the arcing much better.
A main switch by which the whole board may be cut off should be installed but this need not be on the front of the board.
The general rule is that all wires in theaters must be in conduit or armored cable. Metal molding is not considered suitable for the stage side of the theater. There are, however, stage requirements which make the use of some sort of flexible and portable connection necessary and for such purposes stage cables are allowed. All wiring that can be permanently fastened to battens or fastened in other ways; or that is run inside of posts or statuary, must be in conduit or armored cable.
The National Electrical Code Rules are quoted in this chapter wherever they apply and should be followed, not only because these rules outline the best practice but because, throughout the country, inspections will generally be governed by these requirements. Even where the local rules vary somewhat from these rules, it will be found that all apparatus constructed according to them will be favored to a considerable extent.
Anvil Sparks.—These are sometimes produced by arranging the anvil as one pole of a circuit and the hammer as the other. When the hammer leaves the anvil, the spark occurs. A resistance must always be inserted in the circuit if a light or power circuit is employed. One of the most successful methods of producing anvil sparks is shown in Figure 180. When the hammer strikes the anvil the spring follows and strikes the head of the hammer; and when it rebounds the spark occurs. If it is not desired to use a power circuit the spark may be obtained from batteries by the use of a spark coil. Sparks in dueling scenes may be produced in much the same manner.
In some cities the inspection laws require all arcs or sparks, used on the stage, to be enclosed. So far as the authors are aware no really satisfactory method of enclosing anvil sparks has ever been made up. If such an enclosure is to be constructed it must be borne in mind that it must not spoil the illusion nor mar the tone in case the anvil is tuned for use in singing acts. A special combination of metals is on sale at stage-supply dealers by which sparks can be produced without the use of current.
FIGURE 180.
Arc Lamps.—In Figure 181, there is shown an open or flood lamp, also known as the “Olivet”. This style of lamp is used on the stage only for general illumination. As the light from this lamp spreads in all directions it must be brought close to the part to be illuminated and this usually brings it close to the scenery.
All portable stage lamps are hand feed and require close attention on the part of operators. While traveling it sometimes occurs that only high voltage such as 500 or 600 volts is available and in such a case a suitable number of lamps must be connected in series. Hand-feed arc lamps are difficult to start under such circumstances and the following method is often resorted to: Place the carbons of all the lamps connected in series the proper distance apart and connect a small fuse across each gap. When the current is turned on it will melt the fuses and establish the arc.
In Figure 182 we have an illustration of what is known as the spot or lens lamp. This style of lamp is used on the stage, on bridges, or “in front” (in front being the term by which the balcony or galleries are designated in this case). In the figure a “Sciopticon” attachment is shown which is removable. Even very unpretentious shows carry at least one spot lamp and the largest shows often carry 30 or 40 open and spot lamps. Arc lamps are often imitated by an incandescent lamp placed within a suitable globe with the hood made up in the shape of an arc lamp.
FIGURE 183.
Figure 183 is a cut of a stereopticon outfit. Dissolving views require at least two lamps and sometimes three, the third being for the purpose of providing a frame for the views or adding an extra effect, such as falling snow. Two lamps at least are always in use at the same time and it is necessary to provide cables of sufficient carrying capacity for two or three lamps, as the case may be.
Must be constructed entirely of metal except where the use of approved insulating material is necessary.
Must be substantially constructed, and so designed as to provide for proper ventilation, and to prevent sparks being emitted from lamps when same are in operation; and mica must be used for frame insulation.
Front opening must be provided with self-closing hinged door frame, in which wire gauze or glass must be inserted, except in the case of lens lamps, where the front may be stationary, and a solid door be provided on back or side.
Must be so constructed that neither carbons nor live parts will be brought into contact with metal of hood during operation, and arc-lamp frames and standards must be so installed and protected as to prevent the liability of their being grounded.
Switch on standard must be so constructed that accidental contact with any live portion of same will be impossible.
All stranded connections in lamp and at switch and rheostat must be provided with approved lugs.
Rheostats must be plainly marked with their rated capacity in volts and amperes, and, if mounted on a standard, must be raised to a height of at least three inches above the floor. Resistance must be enclosed in a substantial and properly ventilated metal case which affords a clearance of at least one inch between the case and the resistance element.
A competent operator must be in charge of each arc lamp, except that one operator may have charge of two lamps, when they are not more than ten feet apart and are so located that he can properly watch and care for both lamps.
Each lamp should be provided with its own fuses and switch.
Baby Spot Lamp.—This is the name given to a small lens lamp in which an incandescent lamp is used instead of an arc lamp. Such a lamp cannot be used for projection very well but is well suited to illuminate parts of an act that do not require very bright illumination. It is sometimes used to take the place of proscenium side lights. In one well-known production twelve such lamps were used upon scaffolding directly above the proscenium opening. The incandescent lamp is movable for the purpose of focusing; but it not being a “point source”, no such accurate focusing is possible as with arc lamps.
Batteries.—Both primary and secondary, or storage, batteries are extensively used upon the stage. Small dry cells are often used to ring bells or light miniature lamps in the hair or clothes of the chorus. The electromotive force of a cell is independent of the size and depends only upon the materials used; but the current which a battery can deliver varies directly with its size. If we wish to increase the voltage we must connect several cells in series, as indicated in Figure 184; if we have sufficient voltage but lack current we must connect, as in Figure 185. As a general rule, in any circuit, we must connect the battery so that its resistances shall most nearly equal the resistance of the device which it feeds. This means that if the resistance of the device is greater than that of the battery we must connect our battery in series; if it is less we must connect the cells in multiple, as indicated by Figure 185.
When connecting cells in multiple those of the same kind should always be selected. Any cell whose electromotive force is not fully equal to the others will absorb energy and be charged by the others. The resistance of small cells is high and it is best, where size is not objectionable, to use large cells. Storage, or secondary batteries, have low resistance and are capable of delivering very strong currents, even though the voltage be low. The heat is proportional to the square of the current and a certain amperage, with two volts back of it, will produce just as much heat in given resistance as the same amperage with several hundred volts. The sparking in case of a broken circuit or a fuse blowing would, however, be hardly noticeable with the low voltage.
FIGURE 184.
FIGURE 185.
No definite rule is given concerning the fusing of low-voltage storage batteries, but it is good practice to insert a double-pole fuse in each branch circuit; the fuse to be small enough to protect the smallest wire fed through it. The capacity of storage batteries is usually given in “ampere hours”. A 60-ampere-hour battery, for instance, can deliver three amperes for twenty hours or ten amperes for six hours. With every battery there is, however, a certain maximum rate of discharge which should not be exceeded. The battery should not be allowed to run down too low and should be kept well charged. It is best to follow the instructions which the makers send out with them.
Bells.—Electric bells are used on the stage for many purposes. Sometimes they are used as musical instruments, the gongs being properly tuned; at other times they are provided to ring in connection with certain acts; and they are also used for the purpose of signaling. When signals are to be given, which the audience must not hear, it is better to provide buzzers.
FIGURE 186.
Bells can be arranged to operate from power circuits by placing an incandescent lamp, or some other suitable resistance, in series with them; but it is not advisable to do so. It is not safe from a fire-hazard point of view, and also not very practical, since in many places alternating current only can be had and the ordinary bell does not operate well with it. Batteries should always be used for bells and other low-voltage devices.
Where it is desired to operate a number of bells together, they may be arranged in series, as shown in Figure 186, in which the vibrator of one bell is cut out of circuit so that the vibrations of this bell are governed by those of the other. Sets of bells properly tuned are often scattered about and controlled from a keyboard. There are usually eighteen bells in such a set.
Blinding Lights.—In certain acts it is necessary for the actor to work part of the time unseen by the audience. This may easily be arranged for by the use of a number of bright lights placed between him and the audience. These lights, when burning, blind the audience so that they cannot see beyond them. The lamps must be placed in reflectors which throw all light toward the audience. They are arranged either upon the floor of the stage or around cabinets or other devices. The blinding effect depends upon the contrast between the front and the rear of the lamps. Lights should be very bright but the quantity of light must not be sufficient to cause reflected light from the front to illuminate the back of the stage. Where emergency lights are kept burning during the performance it is quite difficult to carry out the blinding effect for any considerable length of time.
Brackets.—Brackets are made up in any of the three ways shown in Figure 187. If the stem is large enough to admit the cable, which should be used to the pin-plug connector, no splice of any kind will be necessary. If the bracket stem is too small for this, fixture wire must be used and a connection from it to the cable must be made. If this is made, as at the extreme right, the back of the canopy must be enclosed in substantial metal. On no account should fixture wire be allowed to extend outside of the stem. The bracket must have some provision by which it can be made to hold its proper position when in place. Sometimes hooks are provided for this purpose and at other times it is held in place by screws in the scenery, as suggested by the back of the canopy shown at A.
Where brackets are used they must be wired entirely on the inside; fixture stem must come through to the back of the scenery and end of stem be properly bushed.