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Alternating Current System.
(Note.-The specification for the low poten- 180. Alter tial system, p. 95 et seq., may be followed in System. general. There should be added a specification for placing converters on poles where so required, and for running secondary mains where a single converter supplies a number of buildings, including the distance that the secondary main must be kept from the primary.)
Street Lighting Circuits-Arc or Incandescent.
(Note.—The specification for the low poten- , 181. Street
Lighting Cirtial system, p. 95 et seq., may be followed in general, but the following additions and modifications should be introduced.)
(Add to sec. 168, p. 96.)
Lamp poles shall be not less than — in length, with tops not less than -- in diameter, and set
of their length in the ground.
183. Gains and Cross-Arms.
(Add to sec. 172, p. 96.)
Where there is but a single wire on a pole a bracket may be used instead of a cross-arm. Where necessary break-arms shall be used to carry wires from the line out to the lamp.
(Note.—Steps may be desirable on lamp poles, if so add to sec. 174, p. 97.)
185. Suspen Lamps shall be suspended at the places sion of Lamps.
located on the attached map by means of (brackets, mast-arms, cross suspension, etc.) The bottom of the lamp to be not less than 12_Red above the roadway.
The lamps and fixtures must be secured against damage or interference through ordinary wind storms, and all wires so connected thać there shall be a minimum danger of short-circuiting or grounding.
186. Fixtures (Incandes
The following fixtures and appliances shall be furnished and erected: water-proof hoods complete with re
flectors, sockets, and bracket
in length complete with post-socket or flange and the necessary guy wires.
feet -- inch weather-proof rope for raising and lowering lamps.
double cleats for winding up surplus rope. feet
inch rope for suspending lamps,
187. Fixtures (Arc. See also Secs. 69, 70, 71, 72, 73 and 74),
water-proof circuit cut-outs for cutting out circuits inside buildings from the
exterior circuit. The “Off” and “On” posi-
outriggers, --- in length for attaching
outriggers, in length for attaching to poles.
inch stranded cable
feet -- inch weather-proof rope for
for winding up surplus rope. (Note.—The specification for wiring must 188. Wiring. be made up with reference to the system or systems to be installed, whether parallel or series wiring with incandescent or arc lamps, or a combination of systems.)
(Note.—The point at which street lighting 189. Point of çirçuits will be controlled will depend much
on the system adopted and on local conditions; it is sometimes absolutely necessary that they shall be controlled from the station; in other cases for the sake of economy or convenience it is desirable to have them controlled from some other point such as the centre of distribution.)
All street lighting circuits shall be controlled by switches at (location).
190. Additions and Deduc
While the schedule is intended to represent very closely the number of lights to be installed, yet as some changes may become necessary during the process of construction, each bidder shall name in his proposal a price to be added to or deducted from the contract price for each light installed in excess of the number specified or which shall be canceled, provided such addition or cancellation involves no change in the work already completed, and shall be along the line of existing circuits. The price shall include lamp, fixtures, extra poles required, and labor.
In order to tabulate clearly and concisely the location and number of outlets for lights, switches, and meters, together with the number of lights per outlet in each individual case, and the capacity of 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,