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123. Sul). division of Riser's Feeders
From the switchboard (or centre of distri
riser's bution) groups of risers
of risers shall te carfeeders
No. 2 to etc.
riser Every conductor in each group of risers
riser tion), 3 group
No. 2 shall feed, etc. feeder
of Risers Feeders )
switchboard From the
the 7 centre of distributions
- and thence 5 upward in (channels, elevator shaft, etc., with location) to their respective junction boxes.
S From the
125. Mains (If taps terminate
iu secondary shall be carried to secondary junction boxes junction
boxes). where all tap lines shall centre. From
No. 1 shall be carried
feeder : No. 2, etc.
(Note.—In certain cases it is advisable to
The terminals of all the feeders
and taps shall be brought together in junc-
(See p. 81, sec. 95.)
(See p. 81, sec. 96.)
Where no gas pipes or other support for the 131. Fixture
Supports. fixture exists, the special form of terminal box designed to furnish such support shall be employed and shall be substantially fixed to a suitable foundation in the ceiling or wall.
All tubes shall be of sufficient size to allow 132. Sizes of the wires to be readily drawn in, withdrawn and reinserted at will. A quarter-inch tube will be permitted only where space is extremely limited.
Tubes, whether concealed or on the surface, should be held in place by metal clips; the use of staples for such purpose will not be allowed where it can be avoided.
The tubes shall be cut squarely, reamed out 134. Joints. smoothly, and the ends joined by the use of the coupling designed for that purpose.
135. Ellow Limitations.
Where more than four elbows are unavoidable, an intersection box. shall be inserted to relieve both the wires and the tubes of strain when the wires are being drawn in.
All tubes shall emerge at outlets in termi- 136. Outlets. nal boxes, leaving the outlets so protected as not to be injured by the plasterers.
To guard against mechanical injury and the destructive action of cement, all floor conduits shall be made of double tube, one tele. scoped within the other, and both the outer and inner tubes joined in the usual manner. The outer tube shall, in the case of contact with cement, be alkali proof. As a further protection, floor tubes shall be covered during construction with a light board. Such other precautions shall be taken to insure the safety of the tubes as the character of the building and work require.
128. Separation of Wires.
Each side of circuits carrying more than
ampères shall be run in a separate tube. Wires forming parts of two distinct circuits shall in no case be inclosed in the same tube.
(See p. 82, sec. 98.)
(See p. 85, sec. 107.)
147. ThreeWire System
Adapted to the Two-Wire
Interior Wiring for Central Station Plants.
This specification contemplates the com- 148, Number plete installation of
incandescent lamps located in blocks as designated on the plans hereto attached and made a part of this specification.
(Note.-Specify whether bids for two-wire 152. System. direct-current systems only, for three-wire direct-current, for two-wire alternating current, or for any system will be considered.)
The fall of potential between the service 153. Variation
iu Pressure. cut-out and the most distant lamp in any building shall not exceed
All wires used inside of buildings shall be 154. Insula. insulated with
of the Work.
All wiring shall be
work, 155. Character
concealed neat in its mechanical appearance and arrangement.