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selves for denoting the number of lights for a given outlet; a convenient way is to locate the outlet with a circle and denote the number of lights by a figure within the circle,
thus (5) is a five-light outlet. To distinguish ￼
side from ceiling outlets, a straight line may be drawn from the circle to the wall to denote
the former, thus (V) is a two-light side outlet. For switches and meters the letters S and M
method used is to indicate the gas outlets by a simple circle while the number of electric lights at the same outlet is denoted by the number of lines terminating in the circle,
thus -i- is a three-light ceiling outlet, -O- is a two-light side outlet, the third line drawn to the wall designating it as a side outlet.
The exact position of outlets may usually be located on the plans, but in certain cases it is also advisable to add explanatory notes to the specification, especially if the lights are to be worked into architectural or decorative designs.
To avoid complication and the confusing of circuits with partition and other lines, it is often more satisfactory to designate in the specification, rather than on the plans, the outlets each switch and meter is to control.
Distribution boxes should be located in the same manner as switches and meters.
If the locations of the vertical risers are determined by other than the contractor, they also should be plainly indicated.
In case the installation is intended to be connected both to dynamos in the building and to an external source of supply, this fact should be taken into consideration in the location of the centre of distribution and of the risers; where the outside mains enter the building overhead it is sometimes advisable from considerations of economy or convenience to have a second centre of distribution located with reference to this external source of supply.
No attempt has been made throughout.the specifications to lay down ironclad rules or to volunteer technical information. It is fairly assumed that no one will attempt to make out a definite and detailed specification who is not himself competent to determine for any installation under consideration the best methods and system to be adopted, and the kind and quality of materials and workmanship required by its purposes or by local conditions. These few preliminary notes are intended merely as suggestions to call to mind points that, through their very simplicity, or obscurity, might escape attention, but yet are deserving of consideration.
The outline given below is one that I have *' outline? often found convenient for use in checking a specification, or for reference in outlining the points to be taken up in detail in making up a specification.
In those cases where a formal specification is not required, as sometimes occurs in the case of a preliminary specification or a specification for a small isolated plant or wiring job, the necessary data for estimates and bids can often be easily and rapidly dictated, item by item, as suggested by these headings, with little liability of making any important omissions.
f Dynamos and erection.