Зображення сторінки

each switch and meter, also the location, catalogue number and incidental information on each fixture and shade, the attached schedules will often be found of great convenience; indeed, in making up estimates, such schedules are almost indispensable and will prove of very considerable assistance if incorporated in the specification. They will also be found useful in checking the accuracy with which the details have been taken from the plans and an aid in checking the work during construction, since they give the detailed distribution in a concise form, free from distracting explanatory clauses or directions, and are more convenient and accessible than plans; plans, too, often have the disadvantage of containing details foreign to the electrical work, which may confuse and mislead.

The shade schedule can often be incorporated in the fixture schedule. The catalogue number of fixtures is added in this schedule in order to keep in mind the exact fixture for which a given shade is intended, thus insuring against mistakes in putting them on.

In the fixture schedule, if sockets are to be furnished by another contractor, the column for same may be cancelled. As a memorandum, notes concerning the supplying of insulating joints or flanges, the wiring of fixtures, etc., may be added. The item " length" is very important and should never be omitted.

The capacity of switches is often marked in lights and is so given in the schedule; it may, however, often be advisable to designate them by their current carrying capacity in amperes to provide for the use of low volt as well as high volt lamps. The form of schedule for switches can also be used for meters, but in this case the current consumed by the lamp should be given and it should be clearly specified whether the meter is to measure direct currents only, alternating currents only, or either direct or alternating currents, also whether two or three wire.

In the lamp schedule the vertical column of outlets gives the total number for each location, the horizontal line across the bottom of the page gives the total number of outlets of each size in the building, and the sum in each case should be the same. The vertical column of lights gives the total number of lights in the building. This sum may be checked from the horizontal line of totals by multiplying those totals by the number of lights per outlet given at the top and adding the results. If the results obtained by the two methods do not agree some mistake has been made either in the arithmetical work or in placing outlets under the wrong heading; the results,.to be correct, must agree. The division into "side" and "ceiling" outlets is important to the contractor, since the quantity both of labor and material required is often very largely dependent upon this relation which may also determine the method of running the circuits.

[ocr errors][table]
« НазадПродовжити »