2990
THE NEW ZEALAND GAZETTE.
[No. 116

(g.) The maximum sag shall be computed on the assumption that the conductor is subjected to a temperature of 122° F.

17. SUPPORTS FOR OVERHEAD LINE.

(a.) All metal-work, including insulator-pins, forming part of supports carrying extra-high-pressure lines in excess of 35,000 volts shall be effectively earthed.

(b.) Every support for overhead electric lines shall be so located as to avoid unduly obstructing pedestrian or vehicular traffic.

(c.) Every support for overhead electric lines shall be of durable material, and of sufficient strength to withstand forces due to wind-pressure, change of direction of line, and unequal length of span. The factor of safety of such supports, if carrying transmission-lines only, shall be such that the moment resulting from a wind-pressure of 30 lb. per square foot of plane surface and 18 lb. per square foot of diametral plane of a cylindrical surface upon the lines and supports shall not exceed one-half the applied moment which is sufficient to cripple the support if of iron, steel, or ferro-concrete, and shall not exceed one-fourth of the breaking-stress in the case of wood. The factor of safety of supports carrying electric distribution-lines shall be 4 in the case of steel, iron, or ferro-concrete, and 5 in the case of wood, calculated upon the ultimate strength of the material, assuming the wind-pressure to be 20 lb. per square foot upon a plane surface and 12 lb. per square foot upon a diametral plane of a cylindrical surface.

(d.) All overhead electric lines shall be attached to suitable insulators carried on cross-arms or brackets of suitable material and cross-section, and they shall be so attached to the insulators or guarded that they cannot fall away from the supports in case they become detached from the insulator. Where such lines are covered with insulating-material they shall be so attached to the insulators that their insulation shall not be impaired thereby.

(e.) Electric distribution-lines at low pressure may be carried on brackets attached to buildings, provided they are inaccessible from any portion of the building without the use of a ladder or other special appliance, and provided also that they are secured in such a manner that they cannot fall or make contact with the building.

18. MAXIMUM LENGTH OF SPAN.

(a.) The distance between supports carrying electric distribution-lines shall, notwithstanding the provisions of clause 15 hereof, not exceed 2½ chains.

(b.) The distance between supports carrying electric lines other than distribution-lines shall be determined by the provisions of clauses 15 and 16.

19. ANGLE OF CROSSING THOROUGHFARES.

Where an overhead electric line crosses from one side of a street to the other the angle formed by the original alignment and the portion of the line crossing the street shall approximate as closely as practicable to a right angle, and shall not exceed 135°. The crossing-span shall be as short as possible.

20. COVERING OF OVERHEAD LINES.

Electric lines at low pressure shall be covered throughout with triple braiding, thoroughly impregnated with weatherproof compound: Provided that where circumstances permit and subject to the undermentioned conditions the lines may, with the written consent of the Minister obtained before the work is commenced, be bare.

Electric lines at high pressure shall be insulated with vulcanized rubber of at least 600-megohm grade: Provided that where circumstances permit and subject to the undermentioned conditions the lines may, with the written consent of the Minister obtained before the work is commenced, be bare.

Electric lines at extra-high pressure shall be bare.

Earthed neutral or intermediate conductors may be bare.

Every pole or support carrying extra-high-pressure lines or high-pressure lines the conductors of which are bare shall have attached to it a plate marked “Danger—Live Wires.”

Bare low-pressure and bare high-pressure electric lines erected with the consent of the Minister as above mentioned shall be subject to the following conditions:—

(a.) The electric lines upon which workmen are engaged shall be disconnected from the source of supply, but if a suitable raised insulated platform is used the electric lines need not be so disconnected.

(b.) When in the opinion of the Minister it is necessary in the interests of the public safety that the use of bare electric lines shall be discontinued, the licensee shall, upon receiving notice from the Minister, and within such time as he may fix, substitute therefor electric lines covered in the manner prescribed in this clause.

(c.) Where telegraph-lines are affected the bare electric lines shall also be subject to the conditions prescribed in clause 25, “Protection of Telegraph-wires, &c.”

(d.) Such further conditions as the Minister may see fit to prescribe.

21. LOW-PRESSURE, HIGH-PRESSURE, AND EXTRA-HIGH-PRESSURE LINES ON SAME POLES.

(a.) Where high-pressure and extra-high-pressure electric lines are supported on the same poles or supports both lines shall be bare, and means shall be provided for automatically and effectively earthing the high-pressure line in the event of the extra-high-pressure line making contact with the high-pressure line.

(b.) Low-pressure and extra-high-pressure electric lines shall not be carried on the same poles or supports.

(c.) Where low-pressure and high-pressure electric lines are supported on the same poles or supports the high-pressure electric line shall be insulated with vulcanized rubber of at least 600-megohm grade. Where, however, circumstances permit, and subject to clauses 20 and 25 hereof, such high-pressure electric lines may be bare, provided that—

(i.) The written consent of the Minister is first obtained;

(ii.) A clearance of at least 4 ft. shall be maintained between the high-pressure and low-pressure lines;

(iii.) The low-pressure electric lines, whether bare or braided, shall be provided with effective earthing-devices;

(iv.) Such further conditions as the Minister may see fit to prescribe.

22. TELEPHONE-LINE ON POLES CARRYING EXTRA-HIGH-PRESSURE WIRES.

(a.) Telephone wire or wires supported on electric-line poles shall be of hard-drawn copper or other suitable material, and shall not be less than No. 12 S.W.G. The minimum clearance between the lowest point of the span and the ground shall be 18 ft.

(b.) The wires shall be suitably guarded against lightning, and shall be fused. Such arrangements shall be made where the telephone is placed as will prevent the possibility of injury resulting to any person using the telephone as the result of a conductor coming into contact with the telephone-wires, or as the result of leakage or of induction.

23. LOCATION OF OVERHEAD LINES.

One side of every street shall be left free by the licensee for telegraph-lines.

Except by permission of the Minister of Telegraphs, or subject to an agreement between the Post and Telegraph Department and the licensee, all overhead electric lines shall be placed on the opposite side of the street to that on which any telegraph-lines exist; and where the erection of the overhead electric lines necessitates an alteration of any existing telegraph-lines, and such alteration is approved by the Minister of Telegraphs, the expense of the alteration shall be borne by the licensee.

In running the electric lines along a street where no telegraph-line exists the licensee shall keep to one side of the street, and in running electric service-lines to the opposite side of the street such lines shall be erected at such a height and in such a manner as not to obstruct any future telegraph-lines.

24. FACILITY FOR SERVICE CONNECTIONS, ETC.

Where electric distribution-lines are on one side of the street and telegraph-lines on the other, and service is required to be given from either to the other side, the licensee and the Minister of Telegraphs shall give to each other reasonable facilities as far as possible to effect supply.

25. PROTECTION OF TELEGRAPH-WIRES, ETC.

The licensee shall take all reasonable precautions in constructing, laying down, placing, and using the electric lines so as not injuriously to affect, whether by induction or otherwise, any telegraph-line, whether such telegraph-line is or is not in existence at the time of the construction, laying-down, or placing of the electric lines.

Where electric lines intersect or menace telegraph-lines the following conditions shall apply:—

(a.) High-pressure electric lines shall be insulated with vulcanized rubber of not less than 600-megohm grade, unless the electric lines are permitted by the Minister to be bare as provided in clause 20, in which case the special conditions of paragraphs (o), (p), (q), (r), and (s) of this clause shall apply.

(b.) Low-pressure electric lines shall be covered with triple braiding thoroughly impregnated with weatherproof com-