OVERHEAD CONSTRUCTION
POLE FITTINGS


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P.O. ENGINEERING DEPT
ENGINEERING INSTRUCTIONS
LINES
OVERHEAD
C3151
Issue 5, 3.11.37
Issue 6, 28.9.59
Issue 7, 1.1.70

POLING
Pole Fittings

1. General
Various pole-fittings such as roofs, finials, saddles and steps, are described in the following paragraphs ; where necessary, instructions are given for fixing. For "Numbering of Poles" see C 3161.

2. Roofs
Roofs for poles are made of galvanized iron and are provided so as to prevent the entry of moisture through the exposed pores at the tip of the pole. They should be fitted to all poles except:-

  1. those carrying a finial,
  2. those used for Light Aerial Lines " (see H 3001),
  3. precut poles, except where, for uniformity or to meet the wishes of Wayleave Grantors, the Sec. Engr. decides that roofs are necessary.

3. Types
Two types are available in each size - "cut" for poles where saddles are required, and "uncut" for poles without saddles. The former type is drilled with a 3/16in. hole in the centre of the ridge and two 17/6in. holes in each side; the latter has two holes in each side. Both types in each size are interchangeable.

4. Sizes
The width of the roof should be slightly greater than the diameter of the tip of the pole. To provide for this, four sizes of each type of roof are available as shown in Table 1.

5. Fitting the roofs
Cutting the top of the pole. If necessary, the tip of the pole should be sawn square. Two cuts sloping at about 45 deg. to the axis of the pole should then be made, as shown in Fig. 1, so that the roof will fit the pole closely. After cutting, the top of the pole should not form a sharp central ridge but should present a flat surface, about 1 inches wide. The cuts should be made so that the roof will fit the pole closely and so that the ridge of the roof will be parallel with the arms, i.e. at right-angles to the direction of the line-wires.

6. If a Saddle is required, a 5/8in. hole should be bored in the centre of the tip of the pole, to a depth sufficient to accommodate that portion of spindle which will protrude from the underside of the saddle.

7. "Creosote and tar" must be thoroughly applied to the exposed end-grain at the pole top before the roof is fixed.



FIG. 1. - CUTTING THE TOP OF THE POLE TO FIT THE ROOF

8. Fixing
Roofs used with Saddles are secured to the pole by means of the fastenings for the saddles, i.e. four "Screws, Coach" The coach-screws, which are of the fetter-drive type, are designed to be driven in with a hammer, all but the last half-inch, which must be screwed home.

9. Fixing
Roofs used without Saddles should be fixed by means of four "Nails, Rosehead, 2 in.''

TABLE 1
TYPES AND SIZES OF ROOF

Width Class of pole on which
generally used
Description
Cut
(for use with saddles)
Uncut
(for use without saddles)
8in. Light Roof No. 1 Roof No. 2
10in. Medium Roof No. 3 Roof No. 4
12in. Stout Roof No. 5 Roof No. 6
14in. A Roof No. 7 Roof No. 8

10. "Saddles, Galvanized"
These are used when it is necessary to erect one or two additional wires in cases where, by so doing, the carrying capacity of the pole will not be exceeded, but where clearance is not available to allow an additional arm to be added without substituting longer poles. As the insulation of the saddle is always lower than that of other wires, this position should not as a rule be used for long circuits. The saddles have a central hole to take either a fin. straight spindle (for a single wire) or a "Bolt, No. 6" (used with a "Spindle, No. 13, 14, or 15") for two wires : a square recess at the bottom of the hole accommodates the nut of the spindle or bolt.

11. Assembly of Saddles and Spindle
The saddle and its spindle should be assembled before the saddle is fixed in position. The washer should be fitted between the top of the saddle and the shoulder of the spindle or head of the "Bolt, No. 6" (if used).

12. Fixing
Saddles should be fixed centrally with the pole, as indicated in para. 8.

13. "Stays, Saddle"
These should be used for saddles on:-

  1. all A-poles (see C 3251)
  2. for all other poles at angles
  3. at all points where saddle-wires are terminated, and
  4. on all LIGHT (and EXTRA LIGHT) poles.

14. Saddle stays are made of galvanized hoop-iron and are available in three sizes, Nos. 1, 2, and 3, for use with "Roofs, Nos. 1, 3, and 5" on average LIGHT, MEDIUM and STOUT poles, respectively. If a saddle is to be fitted where a "Roof, No. 7" is required (e.g. on a STOUT A-pole), a "Stay, Saddle, No. 3" altered locally, should be used.

FIG 2 - SADDLE STAYS

15. Fixing of the stay to the saddle is accomplished by means of the spindle of "Bolt, No. 6" and the assembled stay and saddle is secured to the pole-tip by means of coach-screws (see para. 8). "Wedges, Hardwood" should be inserted between the pole and the saddle-stay as shown in Fig. 2. These are available in four thicknesses, in., in., 1in. and 1in., known as "Nos. 1, 2, 3, and 4" respectively, and should be trimmed, if necessary, so as to fill the triangular space between the pole, the roof and the saddle-stay. The wedges should be fixed to the pole by "Nails, Wire, 2 in." independently of the fixings of the stay.

16. Finials
The use of finials on wooden poles should be restricted to cases where ornamental poles are insisted upon, by wayleave grantors, for poles in places where amenities receive some consideration, and to poles fitted with pole-heads for open-wire or drop-wire distribution. The standard type of finial is illustrated in Fig. 3.

FIG 3. - FINIAL

17. Size
Three sizes are available as shown in Table 2.

TABLE 2
DETAILS OF FINIALS

Diameter
of base
Height Diameter of dowel Class of pole for which
generally used
Rate Book
description
9 18in. 1in. STOUT Finials No. 1
8 16in. 7/8in. MEDIUM Finials No. 2
7 14in. 3/4in. LIGHT Finials No. 3

18. "Collars, Pole Top"
If a pole is of such a diameter that the base of the finial is not large enough to form a suitable cap, a "Collar, Pole Top" should be interposed between the finial and the pole-top. This is a wooden disk lin. thick, diameter 8 to 12 inches to suit the size of pole, with radiused edges and a clearance hole drilled in the middle to admit the dowel-screw of the finial. The top of the pole must not be pared down to the diameter of the base of the finial.

19. Fixing the finial
The finial is fixed to the pole by means of the screwed dowel. To facilitate fixing, the tip of the pole should first be sawn square and a hole, of the same diameter as that of the dowel, drilled in its exact centre to a depth of 3in. Then using a bit of 1/8in. less in diameter, the hole should be continued to a total depth of 6 inches. Finally "Creosote and Tar" should be liberally applied to the cut surfaces, and the finial may then be screwed down by hand.

20. "Steps, Pole"
Steps Pole No. 1 are used for Wooden poles and should be fitted alternately on opposite sides of the pole, at right-angles to the line of wires, i.e. parallel with the arms, and 15in. apart (The distance between any two steps on the same side of the pole will then be 2ft. 6in.). Each step should be fixed by means of three coach-screws (see para. 8). Steps, Pole No. 2 are used on Steel poles (see steel poles section for more information).

Issue 6 additional
Three patterns of Steps, Pole, No. 1 are issued: the standard P.O. type, the pressed steel. type (both of which have three fixing holes in line) and the Barton type, which has one fixing hole on each side level with the tread and one at the lower end of the strut Issue 7 advises that only the Barton step is now supplied)..

Issue 6 additional
Steps, Pole No. 1 are secured to the pole by means of Screws, Coach, which are designed to be driven in with a hammer, all but the last A in, which must be screwed home. The screws should be driven into the pole in a horizontal direction, so that the head of the screw beds firmly on the pole step. The coach screws should only be fitted to sound timber. They should not be driven into shakes or old screw-holes.

21. The highest step should be about 15in. below the bottom arm; on poles carrying only a saddle-wire, the highest step should be about 3ft. 9in. below the wire, and in line with the wire. When new arms are added, the topmost step(s) should be shifted as required.

22. Two additional steps should be fitted at a point 2ft. 6in. below the level of the bottom arm (see Fig. 4). On poles carrying only a saddle-wire, an additional step should be fitted opposite to the highest step.

FIG 4 - SHOWING THE NORMAL SPACING OF STEPS

23. The lowest step should be approximately 15ft. above ground level. On D.P.s on property not accessible to the public, the steps may be continued lower if desired.

NOTE - In the past it was not the practice to provide steps to within 15ft. of the ground, with the result that the bottom step cannot be reached readily from the "Ladder, Extension No. 4", which is now in general use. Existing D.P.s where such a condition exists, and on which frequent work is likely to be necessary, should therefore be fitted with additional steps to within 15ft. of the ground. This should be done, not as a separate and special work, but in conjunction with other work on the D.P. concerned, as opportunity permits.

Issue 7 additional

STEPPING OF POLES WITH ARMS

Issue 7 additional

STEPPING OF AERIAL CABLE AND DROPWIRE POLES

24. On A-poles, steps should be fitted as in paras. 21-23. Up to the double step 3ft. 9in. below the lowest arm (see Fig. 5), the steps should be fitted parallel to the line of the wires: above that point, steps should be at right-angles to the line of the wires, and may be on one or both limbs of the pole, as found most convenient.

25. On poles fitted with a ring-type pole-head, four steps should be fitted at right-angles to one another, at a point 4ft. below the level of the topmost ring. These steps should be set at an angle of 45 degrees to the line of the normal steps (see Fig. 6). Below this point the pole should be fitted with steps in the usual way.

Issue 6 additional
The Barton type step is not suitable for use at the four-step level of a ring-type D.P. as the fixing lugs each side of the tread may overlap and/or prevent the fitting of the Capping, Steel, No. 3 used for protecting the cable at this point.

Issue 6 additional
Stirrups, Pole Step
To enable two men to obtain a secure foothold at the same step position Stirrups, Pole Step, may be attached to the pole step temporarily at the desired position. The stirrup is designed to fit on to Steps Pole, No. 1 (either P.O. or Barton pattern) but not Steps, Pole No. 2. Before attachment of the stirrup it should be ensured that the step and coach screws are capable of bearing the additional load.

STIRRUPS, POLE STEP

 

FIG. 5. - SHOWING THE SPACING OF STEPS ON AN A-POLE

 

FIG 6. - PLAN SHOWING THE ORIENTATION OF THE STEPS ON A
POLE WITH A RING TYPE HEAD

26. For use with iron poles, a special type of step, known as "Clips, Climbing" should be provided.

27. Poles to which street-lighting fittings, road indicator or other signs are attached, should be fitted with steps above the point of attachment of the sign or fitting, to obviate the necessity of using climbers above the sign.

28. Reflectors on Poles. Fixing of Reflectors by A.A. or R. A . C.
The fitting and maintenance of reflex disks authorized under WAYLEAVES, Attachments, A 0511, will be performed by these Bodies.

29. Fixing of Reflectors by the Department.
"Reflectors, Disk" may be fitted at the discretion of the Sec. Engr. on selected poles and on poles in respect of which complaints have been made by Road Authorities or members of the public, where such complaints are considered to be justified.

30. Following the issue of a report on traffic signs by the Ministry of Transport in 1933, the earlier (strip) reflector was made obsolescent and the present reflector introduced.

31. The new reflector is a light metal disk, 6 inches in diameter, with a curved back to facilitate attachment to a pole. Fourteen red, reflex lenses are inserted in the face of the reflector.

32. Fixing Reflectors
To obtain the best effect, reflectors should be fixed in such a position as will ensure correct alignment with oncoming traffic. In the past there has been a tendency to fix reflectors at too great a height above the ground line; the ideal height is 3ft. 6in., measured from the crown of the road to the lower edge of the reflector. Where reflectors fitted at this height are liable to be obscured, it will, of course, be necessary to exceed this height, but it should be exceeded by as little as possible, and in no instance should the height be more than 6ft. 9in.


Pole Fittings



Earthing and Step provision

 

Roofs, Finials and Rings type distribution


 

 
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Last revised: April 03, 2021

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