OVERHEAD CONSTRUCTION
ERECTION OF OPEN WIRES


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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 E 3064).

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

  1. 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.

  2. 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 E 3064 and E 3080.

  3. "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 E 3070). A joint should not be made in the middle of a span, however, so as to comply with E 3079.

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 J 1001 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 J 1201 should be followed explicitly when erecting wire in the vicinity of, or over, Overhead Power lines.
 

 
 
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Last revised: April 05, 2021

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