Feb. 23.] THE NEW ZEALAND GAZETTE. 569

wire at its entrance to the power-station, and on each high-tension aerial wire leading into transformers. One side of each lightning-guard shall be connected direct to an efficient earth, which shall be provided, in the case of transformers, at the site of the transformer being protected. No wire smaller than a No. 7/16 standard wire gauge stranded wire, which may be of galvanised iron, shall be used for making earth-connections. The wire shall be run as straight as possible, shall be securely fastened to the poles, and protected for at least 8 ft. from the ground from liability of damage or of being interfered with. 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. The iron case of each transformer shall be electrically connected direct with the earth at its site.

14. Where wires on the transmission-line cross other wires, either telephone or telegraph, they shall cross at least 3 ft. above, and as nearly at a right angle as possible. At all such crossings no span shall exceed 1½ chains in length where practicable; and all wires on the transmission-line shall be insulated with not less than 600-megohms-per-mile grade of vulcanised-rubber insulation, taped and braided, and be efficiently suspended from steel bearer-wires by strong rawhide hangers, spaced not more than 15 in. apart, or by small porcelain insulators firmly fastened to the bearer-wires, which shall be securely attached to triple-shed porcelain insulators. The telephone and telegraph wires at such crossings shall also be insulated, if deemed to be necessary, and at the Corporation’s expense.

15. The transmission-lines shall be patrolled at least once a week, and insulation shall be maintained so that the minimum of all three wires tested as one wire shall not be less than 0·15 of a megohm when tested with a voltage equal to that used in transmitting energy. Suitable means shall be provided for the immediate indication of leakage. Daily tests shall be made and recorded.

16. Distribution to consumers shall be on the three-phase four-wire system—the fourth or neutral wire being connected to the centre of the secondary star winding of the transformers, and that centre point of the transformer-winding shall be earthed.

17. Bare hard-drawn copper wire may be used for distribution to consumers.

18. The voltage between the neutral wire and any of the outers shall approximate to 220 volts, and that between any two outers to 380 volts.

19. Where primary and secondary wires are run on the same poles, both primary and secondary shall be insulated with not less than 600-megohms-per-mile grade of vulcanised rubber, taped, braided, and compounded. All insulated aerial conductors should be of hard-drawn copper. If they consist of soft copper they shall be suspended in a satisfactory manner from suitable steel bearer-wires.

20. The maximum declared pressure for lighting purposes (except arc lamps) shall not exceed 220 volts at any pair of terminals on a consumer’s premises. For power purposes motors may be connected across the three outers of the distribution system, and the maximum pressure between any pair of terminals shall not exceed 380 volts.

21. The low-tension electric-lighting lines and wires shall be aerial throughout, and shall be placed on one side only of any road or street along which they may run. Where telegraph or telephone lines exist in any street or road along which it may be desired to place electric-lighting lines, the latter shall be run on the opposite side of the street or road to that on which the telegraph or telephone lines run, except by permission from the Electric Telegraph Commissioner.

After the opening of the system for the supply of energy, a notice shall be given of every further extension, through the Postmaster at Inglewood, to the Superintendent of Electric Lines, and in such notice particulars of the proposed extension shall be given.

22. Where the erection of the electric-light line or wires necessitates the alteration of existing telegraph or telephone lines or wires, the expense of such alterations shall be borne by the Corporation.

23. The maximum working-current in any conductor shall not be sufficient to raise the temperature of the conductor, or any part thereof, to such an extent as to materially alter the physical condition or specific resistance of the insulating covering, if any, or in any case to raise such temperature to a greater extent than 130° Fahr. The cross-sectional area and conductivity at joints must be sufficient to avoid local heating, and the joints must be carefully made, using resin as a flux, and must be protected against corrosion. The sectional area of all conductors from any distribution-board on the consumer’s premises must be maintained throughout the circuit, and joints should be made only when branching off a circuit, and should be at least 8 in. distant from a joint in any other conductor.

24. 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 wire, each separate wire shall be at least as large as No. 20 standard wire gauge.

25. 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 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.

26. 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.

27. Every low-tension main shall be tested for insulation after having been placed in position and before it is used for the purposes of supply, the testing-pressure being at least 220 volts, and the Corporation shall duly record the results of the tests of each main or section of a main.

28. The insulation of every complete low-tension distribution-circuit used for the supply of energy, 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. Every leakage shall be remedied without delay.

29. Every low-tension aerial line shall be attached to supports at intervals not exceeding 200 ft., where the direction of the line is straight, or 150 ft. where the direction is curved or where the line makes a horizontal angle at the point of support.

30. Every support for an aerial line shall be of a durable material, and 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 suspending wires, and for all other parts of the structure, at least 6, taking the maximum possible wind-pressure at 20 lb. per square foot.

Every support, if of metal, shall be efficiently connected with earth.

31. All aerial lines shall be attached to porcelain insulators, and shall be so guarded that they cannot fall away from the support.

32. Any aerial line or wire for distribution purposes shall not in any part thereof be at a less height from the ground than 18 ft., or, where railways are crossed over, 22 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 verandas have to be passed, wooden brackets, suitably strong and securely fastened to the verandas or buildings, may be used to support the aerial wires, which shall be so placed on the brackets as not to be in any way a source of danger.

33. 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.

34. Where an aerial line 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.

35. 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.

36. Where telegraph or telephone wires are crossed either over or under by the low-pressure electric light and power wires, a distance of at least 3 ft. shall separate the former from the latter. The telegraph and telephone wires shall be insulated, if deemed necessary, throughout the whole length of the span intersected, and when the crossing is near a pole the spans on each side of the pole shall be insulated if required. The distribution-wires shall 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 wires shall not come into contact with each other. The distribution-wires may also pass through the telegraph and telephone wires on special permission being obtained in each case. When they are taken through they shall be insulated with not less than 600-megohms-per-mile grade of vulcanised rubber, and the insulation shall extend as is indicated in the preceding part of this clause. They shall be affixed to porcelain insulators, suitably attached to the arms on each side of the line being passed through, and be then taken through bell-mouthed iron pipe secured to the arms. The