Mar. 2.] THE NEW ZEALAND GAZETTE. 635

shall be as nearly at a right angle as possible. Where the telegraph and telephone wires are crossed over they shall be insulated to the satisfaction of the Electric Telegraph Commissioner, if such be found necessary, and at the Corporation’s expense.

10. Excepting where bare copper wire has been permitted to be used on the transmission-line, all the high-tension aerial conductors shall be continuously covered with not less than 600-megohms-per-mile grade of rubber insulation. The conductors shall be of stranded copper, tinned; and the insulation shall consist of a layer of pure rubber overlaid with vulcanised rubber, taped, braided, and served with preservative compound.

11. The transmission-line shall be on the opposite side of the road or street to that on which the telegraph and telephone lines are run. It shall be patrolled throughout its whole length at least once a week, and its insulation shall be so maintained that the maximum leakage shall not exceed one-thousandth part of the maximum supply-current. Tests shall be made weekly and recorded.

12. The transmission-lines shall terminate in the distributing-station at New Plymouth. This station shall contain a non-inflammable switchboard mounted on iron, which shall be equipped with switches, fuses, and other apparatus suitable for controlling all the high-tension circuits. The street, private, and arc-lighting high-tension circuits shall be distributed from this station to transformers placed in the distributing-station or on poles, or in suitably constructed underground chambers which shall not be liable to be flooded. High-tension distribution may also be made to transformers direct from the transmission-line. The wiring of the interior of the distributing-station shall be of stranded copper insulated with rubber, and the insulation shall be that known as 2,500 megohms grade, or any other satisfactory and approved insulation.

13. Transformers shall have an earthing shield between the primary and secondary coils, and shall have easily removable fuses for the primary circuit. Transformers for use outside shall be fitted with watertight cast-iron cases, and shall be affixed to poles so as to be inaccessible except by the use of a ladder or other special appliance. Every transformer shall have its iron case and shield effectively connected with earth.

14. No wire smaller than 7/16 standard wire gauge shall be used for making the lightning-guard, earthing-device, and transformer-case earth connections. The earth-wires may be of galvanised iron, and shall be stranded and properly stapled to the wooden poles. They shall be run as straight as possible, and be properly connected to an efficient earth which shall be provided at the site of the lightning-guard, transformer, or other apparatus or appliance required to be earthed. A test shall be made every three months, and oftener if required, of all earths, to secure that the earth-wire is intact and that the earth is effective.

15. Cables shall be run aerially for distributing the high-tension current from the distributing-station to the transformers, and they may be run on the same poles as the transmission-wires. Where cables are led to and from transformer-chambers they shall be protected on the poles by being run in iron pipe, which shall be effectively earthed.

16. Where cables for street and private lighting are carried on the same poles the length of any span shall not exceed 150ft. Where cables for each kind of lighting are carried on separate poles, or where poles are carrying low-tension wires only, the spans shall not exceed 200 ft. where the direction of the line is straight, or 150 ft. where the direction is curved, or where the wires make a horizontal angle at the point of support.

17. The low-tension distribution may be on the three-wire or the two-wire system. When the three-wire system is used, current shall be transformed from 2,000 volts to approximately 440 volts between the outer wires, so that there shall be about 220 volts between each outer and the neutral wire, which shall be earthed. The supply to street-lighting incandescent lamps and to private consumers for lighting purposes shall be at 220 volts. If any portion of the low-tension distribution be on the two-wire system, the central point of the secondary winding of the transformer shall be earthed. The low-tension distribution-wires shall be aerial throughout, except where they may be within transformer-chambers. They may be bare, and shall consist of hard-drawn copper, and shall be placed where they run on roads or streets on the opposite side of the roads or streets where any telegraph or telephone line exists at the time of their erection, unless otherwise permitted by the Electric Telegraph Commissioner.

18. Where the erection of the electric lines or wires necessitates the alteration of existing telegraph or telephone lines or wires, the expense of such alteration shall be borne by the Corporation.

19. The sectional area of the conductor in any electric line for distribution purposes laid or erected in any street shall not be less than the area of a circular wire 100 mils in diameter, and where the conductor is formed of a strand of wires each separate wire shall be at least as large as No. 20 standard wire gauge.

20. All material used for insulating electric lines or apparatus shall be of the best quality, and thoroughly durable and efficient, having regard to the conditions of its use. Suitable provision shall be made where necessary for the protection of the insulating material against injury or removal.

If the protection so provided be wholly or partly metallic it shall be efficiently connected with earth.

21. Any metallic body to be “efficiently connected with earth” shall be connected with the general mass of the earth in such manner as will insure at all times an immediate and safe discharge of electrical energy.

22. The insulation of every complete high-tension distribution-circuit, including all machinery, apparatus, and devices forming part of or in connection with such circuit, shall be so maintained that the leakage-current shall not under any conditions exceed one-thousandth part of the maximum supply-current in such circuit. Suitable means shall be provided for the immediate indication and for the localisation of leakage. Every leakage shall be remedied without delay.

Every such circuit shall be tested for insulation at least once in every week, and the Corporation shall duly record the results of the testings.

23. Every support for an aerial line shall be properly stayed against forces due to wind-pressure, change of direction of the line, or unequal lengths of span. The factor of safety shall be for all aerial lines and wires and for all other parts of the structure at least 6, taking the maximum possible wind-pressure at 20 lb. per square foot.

24. All the high-tension distribution-wires and the low-tension wires shall be attached to double-shed porcelain insulators carried on cross-arms of suitable material and cross-section, and they shall be so attached to the insulators or guarded that they cannot fall away from the support.

25. Any aerial wire used either for high-tension transmission, for high- or low-tension distribution, or for telephone service shall not in any part thereof be at a less height from the ground than 18 ft., or within 5 ft. measured horizontally or 7 ft. measured vertically from any building or erection other than a support for the line, except where brought into a building for the purpose of supply. Where the wires cross the railway-line the minimum height of all shall be 22 ft.

26. Service lines from aerial lines shall be led as directly as possible to insulators firmly attached to some portion of the consumer’s premises which is not accessible to any person without the use of a ladder or other special appliance. Every portion of any service line which is outside a building but is within 7 ft. from the building shall be completely enclosed in stout indiarubber tubing.

27. Where an aerial wire crosses a street the angle between the line and the direction of the street at the place of crossing shall not be less than 60°, and the spans shall be as short as possible.

28. Where an aerial line crosses or is in proximity to any metallic substance, precautions shall be taken against the possibility of the line coming into contact with the metallic substance, or of the metallic substance coming into contact with the line, by breakage or otherwise.

29. Where telegraph or telephone wires are crossed either over or under by the high- or low-pressure electric-light wires, there shall be a distance of at least 2 ft. between the telephone and the electric-light wires, and the former shall, if deemed necessary, be insulated throughout the whole length of the span intersected, and when the crossing is near a telegraph or telephone pole the spans on each side of the pole shall be insulated if required. The low-pressure wires shall also be rubber-insulated at such crossings either over the whole span or over such portion of it as will insure that uninsulated portions of the telegraph or telephone and of the low-tension electric-light wires shall not come into contact with each other. Where it may be required to cross through telegraph or telephone wires with high- and low-tension distribution-wires, such crossings shall be subject to the requirements of clause 9. The low-pressure wires shall be insulated with vulcanised rubber of 600-megohms-per-mile grade, and the insulation shall extend as is indicated in the preceding part of this clause. This class of insulation shall apply to the low-tension distribution-wires wherever it may be found necessary to cover them with an insulating material. The cost of insulating the telegraph and telephone wires shall be borne by the Corporation.

30. Efficient guard-wires shall be erected in a manner to meet with the approval of the Electric Telegraph Commissioner at all crossings and places where either transmission or distribution electric-lighting wires intersect telegraph or telephone wires as may be required by the Commissioner to be so protected. The Corporation shall bear the expense of such guard-wires in all cases where an electric-lighting wire intersects a telegraph or telephone wire previously existing.

31. Every aerial line, including its supports, its con-