Sept. 25.] THE NEW ZEALAND GAZETTE. 2879

voltmeter to record the pressure between the lines at their entrance to the consumers’ premises, and shall supply to the Inspecting Engineer a chart showing the variations in voltage between the lines at this point for a period of seven consecutive days. If the variations thus recorded exceed the above limits, the Council shall take immediate steps to comply with this regulation. If after thirty days a similar chart shows that the above limits of variation in voltage are not complied with, a breach of these regulations shall be deemed to have been committed. If the accuracy of the Council’s recording voltmeter is questioned by the consumer, a standard instrument shall be supplied by the Inspecting Engineer, the readings of which shall be accepted as final.

SWITCHBOARD.

5. All switchboards shall be made of and mounted on material that is not inflammable, and no switchboard conductor shall carry electric current at a density exceeding one thousand amperes per square inch. No conductor at a pressure above 600 volts shall be exposed on the front of any switchboard, and the back of any switchboard carrying exposed conductors at a pressure over 600 volts shall be screened off and accessible only to authorized persons.

CIRCUIT-BREAKERS.

6. All outgoing feeders and distributors from any powerhouse or sub-station shall be provided with automatic circuit-breakers or fuses, set to open circuit at 50 per cent. excess current over the rated full load of such feeder or distributor, with a time-limit not exceeding ten seconds.

DISTRIBUTION.

7. The distribution may be carried out either by underground or overhead conductors, provided that if at any time it is deemed by the Minister to be detrimental to the public safety for the conductors or any particular class of conductors to be overhead they shall, on receipt of notification to that effect from the Minister, and within ten months of such notification, be laid underground, and all consequent and necessary alterations made by and at the cost of the Council.

OVERHEAD ELECTRIC LINES.

8. Overhead electric lines at a pressure of 460 volts or less shall be of stranded hard-drawn copper, aluminium, or other material of not less than ·0129 square inches in section, provided that service wires of short span may be not less than ·0072 square inches. The lines shall be covered throughout with triple braiding thoroughly impregnated with weather-proofing compound, provided that where circumstances permit the lines may, with the consent of the Minister, be bare.

Electric lines at a pressure exceeding 460 volts shall be insulated, and may be either laid underground or carried overhead. If carried overhead the electric lines shall be insulated with vulcanized indiarubber of 600-megohm grade, or lead-covered and suspended from bearer-wires; provided that where circumstances permit, consent of the Minister may be obtained to such electric lines being bare and carried overhead. The sheathing of lead-covered cables and all bearer-wires shall be earthed.

The stress in overhead conductors shall not exceed 25,000 lb. per square inch for copper and 12,000 lb. per square inch for aluminium in the extreme case of a temperature of 20° Fahr. and a wind-pressure of 18 lb. per square foot of diametrical plane occurring simultaneously. The span between supports and the sag shall be determined to conform with the above limiting stresses, provided that the span shall not exceed 200 ft.

No overhead electric lines shall come within 2 ft. of any other aerial wires or cables except where it may be permitted to pass either wires between other wires at a pole or support.

SUPPORTS FOR OVERHEAD ELECTRIC LINES.

9. All overhead electric lines at a pressure not exceeding 460 volts shall be carried at a minimum height of 18 ft. above the ground.

All overhead electric lines at a pressure over 460 volts shall be carried at a minimum height of 22 ft. above the ground.

Series street-lighting wires insulated with 600-megohm grade indiarubber may be carried at a minimum height of 18 ft. above the ground.

All aerial wires shall be attached to suitable 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. Conductors, covered with insulating material, shall be so attached that their insulation shall not be impaired where they are secured to the insulator.

Every support for an aerial line shall be of durable material, and properly strengthened against forces due to wind-pressure.

change of direction of line, and unequal length of span. The factor of safety of such supports shall be at least three if of iron, steel, or reinforced concrete, and four if of wood, taking into consideration all possible stresses, including wind-pressure at 30 lb. per square foot on plane surfaces and 18 lb. per square foot of diametrical plane for cylindrical surfaces.

LOCATION OF OVERHEAD LINES.

10. Except by permission of the Minister of Telegraphs, or subject to an agreement between the Post and Telegraph Department and the Council, all overhead electric-light pole 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 electric-light wires necessitates the alteration of any existing telegraph wires, and such alteration is approved by the Minister of Telegraphs, the expense of the alteration shall be borne by the Council.

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

In running the lines authorized by this license through streets where no telegraph line exists the Council shall keep to the one side of the street, and in running wires to the opposite side of the street the Council shall arrange so as to interfere as little as possible with the route on that side of any future telegraph line.

TELEGRAPH AND TELEPHONE WIRE CROSSINGS.

11. Where electric lines are permitted to be supported on telegraph poles, all details of the support and of the insulation of the adjacent spans shall be approved by the Minister of Telegraphs, who may require such electric lines at any time to be removed from such telegraph poles, on reasonable notice and without compensation of any description.

Where overhead electric lines at a pressure not exceeding 460 volts cross telegraph lines the electric lines shall be protected for the crossing-span with a triple covering of jute braiding and thoroughly compounded. Where overhead electric lines at high or extra high pressure cross telegraph lines, the electric lines shall be subject to special conditions to be imposed by the Minister of Telegraphs in each case of such crossing.

The cost of all necessary guard-wires and special provisions required to comply with this clause, or deemed to be necessary as a protection to telegraph wires generally, shall be borne by the Council, whether the telegraph lines are erected before or after the electric lines. In the latter case the Council, on receipt of notice from the local officer of the Telegraph Department that it is proposed to run a telegraph line along the route, shall forthwith make the necessary changes required to comply with this clause at any points at which electric lines already cross such routes.

RAILWAY CROSSINGS.

12. No work of any nature shall be erected or constructed upon, over, or under any part of the New Zealand Government railways until the Board has obtained the consent of the Minister of Railways thereto, as required by section 4 of the Government Railways Amendment Act, 1910 (No. 2).

SERVICE CONNECTIONS TO OVERHEAD LINES.

13. Service lines from aerial lines shall be taken from insulators, and shall not be tapped off between insulators. They 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 and accessible therefrom shall be rubber-insulated.

MAINTENANCE.

14. Every aerial line, including its supports, its conductors, and their insulating covering, and all structural parts and electric appliances and devices belonging to or connected with the line, shall be duly and efficiently maintained by the Council as regards both electrical and mechanical conditions.

TRANSFORMERS.

15. Transformers shall be placed either on poles or in substations. The cases of all transformers shall be earthed by means of a copper conductor at least ·022 square inch in section. Within sub-stations all high-tension conductors shall be thoroughly insulated or protected from accidental contact, the walls shall be lined with plaster, sheet asbestos, or other insulating material, a substantial insulating rubber mat and rubber gloves shall be supplied, and the sub-station shall be entirely inaccessible to unauthorized persons.