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P.O. Engineering Instructions
Lines
Overhead
E3055
Issue 1, 27.9.37
WIRING
Erection of Open Wires
1. General
This Instruction presupposes the erection of the poles, the fitting of the
stays, and the fixing of the spindles and insulators, etc., and indicates the
methods to be adopted in handling the coils of wire and elevating the wire to
such a position as shall permit regulation to be carried out (see E3064).
2. Coils of Wire
Line-wire is supplied in coils of a size convenient to handle, the turns of the
coil are secured by 4in. binders of string or wire and the whole is swathed in a
protective wrapping. This latter should not be removed until all preparations
for paying out the wire have been made. This precaution ensures that a minimum
of mechanical damage is done to the surface of the wire when handling the coil.
3. 40lb. cadmium-copper wire is intended to be paid out by hand,
and, accordingly, the coils are small (10in. diameter and 15 to 30lb. weight).
The internal diameter of the coil for all other gauges of wire is approximately
20in., so that it fits conveniently on to the drum of the "Barrow, Drum, Wheel";
the weight of coil varies from 50 to 140lb. for copper and cadmium-copper wires,
from 15 to 120lb. for iron line-wires, and from 5 to 14lb. for iron binding
wire.
4. Paying-out by hand
40lb. wire and small coils of wires of other gauges can conveniently be paid out
by hand. The wrapping should be removed, the coil-binders cut, and the makers'
oval, copper label removed. It is generally easier to pay out the wire from the
outer end of the coil. The inner end of the coil should then be twisted round
the last three or four inner turns, so as to prevent the coil from untwisting.
5. The coil should be held in a plane at right-angles to the
line, and the wire should be paid out one turn at a time. After 4 or 5 turns
have been released, the coil should be reversed so as to pay out from its
opposite side. This allows the coils of the individual turns to neutralize each
other and avoids the formation of kinks.
6. Paying-out by "Barrow, Drum, Wheel"
Large coils of wire are easier to pay out by using a drum-barrow (see Fig. 1).
The purpose of the brake is to prevent the formation of kinks and to check the
revolutions of the drum when paying-out ceases.
FIG. 1
DRUM BARROW
7. Kinks
Whilst careful paying-out will obviate the formation of kinks, if such
irregularities are formed they should not be straightened out, but should be cut
out and a "through" joint made at a convenient point.
8. Erection - New lines and outer arm-positions
If the wire is to occupy "outer" positions on the arms, or if it is the first
wire to be erected on the pole-line, it should first be terminated and then
paid-out by carrying the coil along the line. It should simultaneously be
hoisted into the appropriate position on the arms, by using "Rods, Pruning,
Hooks" or sash-line, whichever is the more convenient.
9. Erection - Inner arm-positions
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Threading - If the wire is to occupy an inner arm-position
on a line of existing wires, it should be erected so as to avoid contact
with working circuits, To this end, it may be necessary to manipulate the
coil from the terminal point and to thread the free end of the wire over the
arm at each pole.
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Use of "Arms, Extension" (Ladder Arms) - These should be
used if working circuits lie in positions directly below those to be
occupied by the new wire. Fig. 2 shows an extension arm in position. The
wire may be paid-out and raised into the insulated slots of the extension
arm, as described in para.. 7. It may then be temporarily terminated and
sufficient tension applied to enable it to be lifted from the insulated
slots to its final position on the arm without making contact with the
existing and working circuits on the line. Regulation and final termination
may then be made as described in E3064 and E3080.
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"Tools, Wire Stringing" and "Sockets for" used in
conjunction with "Rods Pruning" have a limited if useful application to
straight sections of line and where there is no risk of contact with
existing wires vertically beneath the wire being erected. Figs. 3, 4 and 5
show the method of using the tools. The socket may also be inverted, if
required, and so used to lift wires into position.
FIG. 2
DIAGRAM SHOWING "ARM, EXTENSION" FIXED ON WOODEN ARM, FOR THE ERECTION OF WIRES
FIG. 3
"TOOLS, WIRE, STRINGING" AND "SOCKETS FOR", ASSEMBLED WITH "RODS PRUNING" FOR
THREADING WIRE FOR AN INSIDE ARM-POSITION
FIG. 4
THE TOOL IN POSITION ON THE ARM
FIG. 5
THE TOOL, FOLLOWED BY THE LINE-WIRE, BEING PULLED OVER THE ARM
10. Jointing of coils
Where wiring operations are being resumed after cessation (e.g. due to a coil
being exhausted), and termination is unnecessary, the end of the new coil should
be connected to the end of the wire of the previous run by using a "through"
joint (see E3070). A joint should not be made in the middle of a span, however,
so as to comply with E3079.
11. Overhouse work
If wires are to be erected over roofs, the preliminary use of sash-line is
necessary so as to draw the wire over obstacles, such as streets and
light-wells. Whilst, if the distance intervening is not great (say, a dozen
yards) the coil of sash-line can conveniently, and with a little practice, be
thrown from one point easy of access to another, this method of bridging two
points is not to be recommended, except as a last resort. It should never be
used when crossing public thoroughfares or when there is the danger of an
unsuccessful throw causing the sash-line to strike windows below. Heavy objects,
e.g. pliers, must not be attached to the thrown coil.
12. In general, when crossing a thoroughfare, a length of
sash-line should be lowered from a convenient building on opposite sides of the
street, joined when they reach the ground, and then drawn aloft. One end of the
sash-line may then be tied to the main portion of the line, and the line, thus
doubled, drawn back across the obstacle. In this way, an "endless belt" or loop
can be formed, to which may be lashed the ends of a succession of lengths of
wire as each is erected and made off temporarily to its insulator. The endless
belt is particularly useful when the number of wires to be erected is greater
than the number of coils of wire available.
13. Interference with Traffic
Precautions must be taken to avoid interference with, or injury to, pedestrian
or vehicular traffic. At any point where there is a risk of this occurring, e.g.
at a road-bend, the wire must be pulled up by hand-tension and bound-in
temporarily.
14. Precautions against accidents
The provisions of J1001 and RG71 ("Precautions against accidents") must be
strictly observed, particularly when working at road-bends and points of
overhanging.
15. Work in the vicinity of Overhead Power lines
The Instructions detailed in J1201 should be followed explicitly when erecting
wire in the vicinity of, or over, Overhead Power lines.
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