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shall not be dragged along the ground, over cross-arms or through trees in such a way as to injure the insulation; and shall not be allowed to sag unduly between supports, allowance being made for expansion and contraction with changes of temperature. All necessary and proper precautions shall be taken in passing over, through or near buildings of every description, through trees, crossing other lines, turning corners, etc.
Pressure wires shall be carried from the (switchboard) to each centre of distribution unless such centres are connected by an equalizing main, in which case the pressure wires shall be carried to a point on the equalizing main electrically equidistant from the centres of distribution which it connects.
177. joints. Joints shall be mechanically strong and secure so that no movement of the two ends relatively to each other is possible, and shall be carefully sweat-soldered, the joint being wiped free from any excess of flux; the solder shall be relied on only to give good electrical connection.
An efficient lightning arrester shall he^^Lightnins placed on the pole, connected to the line
and to a permanent ground for every
The mains shall be so proportioned m-F*Ja$mum that the maximum fall of potential be- Potentlaltween the centre of distribution and any service cut-out, including the loss in any
transforming device, shall not exceed
per cent, under full load.
Alternating Current System.
(Note.—The specification for the low- isa
potential system, p. 120, et seq., may be Sy8temfollowed in 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.
181. street (Note.—The specification for the low
Lighting Cir- v
cmts. potential system, p. 120, et seq., may be followed in general but the following additions and modifications should be introduced.)
182. poles. (Add to sec. 168, p. 121.)
Lamp poles shall be not less than
in length, with tops not less than in
diameter, and set of their length in
183. Gamsaud (Add to sec. 172, p. 122.)
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.
184. steps. (Note.—Steps may be desirable on lamp
poles, if so add to sec. 174, p. 123.)
sion'JESSSL Lamps shall be suspended at the places located on the attached map by means of (brackets, mast-arms, cross suspension, etc.) The bottom of the lamp to be not less than above the roadway.
The lamps and fixtures must be secured against damage or interference through ordinary wind storms, and all wires so connected that there shall be a minimum danger of short-circuiting or grounding.
The following fixtures and appliances 186. Futures shall be furnished and erected: (I?S3).e""
water-proof hoods complete with
reflectors, sockets, and
I bracket . I attachments. j cross-suspension \
goose-neck brackets, in length
complete with post-socket or flange
feet inch weather-proof rope
for raising and lowering lamps.
double cleats for winding up surplus rope.
feet inch rope for suspending
lamps, , c p. volt
is?. Fixtures water-proof circuit cut-outs for
7^73 ind 74). cutting out circuits inside buildings from the exterior circuit. The " Off" and "On" positions shall be plainlymarked and the switch shall be so constructed that when at the position marked " Off" the wires on the inside shall be entirely cut out of the main circuit.
outriggers, in length for attaching to the exterior of buildings.
outriggers, in length for attaching to poles.
| ornamental} P°le toPs
mast arms, in length, with
proper arrangement for raising and lowering lamps. Bidders shall submit design of mast-arm recommended. sleet-proof pulleys.