July 12.] THE NEW ZEALAND GAZETTE. 2405

be earthed, and the cords shall be immersed in water at the time of the test and for twenty-four hours immediately prior thereto.
(3) Subsequent to the above test the insulation resistance of flexible cords with vulcanized-rubber insulation shall not be less than that given in Table XI in the Third Schedule hereto. This latter test shall be made after one minute’s electrification at a pressure of not less than 500 volts and at a temperature of 60° F., and in the case of high-insulation cords the test shall be made while they are still immersed in water as aforesaid.
(4) The pressure for all the above tests shall be derived from a source having a rated output of not less than 5 kilowatts.
(5) Cables and flexible cords which have to be tested when immersed in water may be tested before the protective coverings are applied, or they may be tested as finished cables, in which case the protective coverings will be damaged by the water, and shall be replaced before use.
(6) The dielectric of flexible cords shall also withstand the tests specified by subclause (2) of Regulation 95 hereof.

IDENTIFICATION OF CABLES BY COLOUR.

99. In all cables, including flexible cords, red shall distinguish the live conductor, and black the neutral or common return. This applies throughout the installation to the current-consuming device.

INSTALLING AND FIXING OF CONDUCTORS AND CABLES.

SERVICE MAINS.

100. Service mains shall in all cases be—
     (a) Enclosed in screwed conduit (Class T in the Second Schedule hereto) which includes no other cables; or
     (b) Armoured cables (Class R in the Second Schedule hereto); or
     (c) Lead-covered cable embedded in bitumen.

BARE CONDUCTORS AND AERIALS.

Bare Conductors.

101. Bare conductors may be used as collector or trolley wires for travelling-cranes and similar appliances and for battery connections.
102. They shall be supported upon insulators, and so spaced that risk of accidental contact between the conductors themselves or between conductors and walls or any other conducting structure is reduced to a minimum.
103. At each straining-point—i.e., at the ends of each conductor—efficient straining-gear fitted with double insulation shall be provided.
104. The circuit supplying current to such bare conductors shall, except in the case of the regulating cells of batteries, be protected either by a suitable circuit-breaker or by a suitable switch and fuse.
105. Bare conductors extended to positions liable to lightning-discharge shall be fitted with lightning-arresters on each pole or phase.
106. Wall rosettes or brackets used as supports for span-wires shall not be fixed within 12 in. of any gas-pipe.
107. Except as hereinbefore specified, bare conductors shall be used only in positions not ordinarily accessible to unauthorized persons and under such circumstances as may be sanctioned by the Authorized Inspector.

Aerials.

108. (1) Where the length of an aerial line does not exceed 2 chains, the conductors shall consist of not less than seven strands, and the minimum size of conductor shall be 7/-029 in.
     (2) The wires shall be covered with rubber insulation in accordance with Regulation 87 hereof, and be braided, except that a multiple-earthed neutral may be bare.
     (3) Where the length of an aerial line exceeds 2 chains the provisions of the Electric Supply Regulations, 1927, shall apply.

109. (1) In no case shall aerials be run at any less height than 9 ft. above the ground level.
     (2) They shall be at a height above ground-level of at least—
     (a) 10 ft. in any part of the premises used by private passenger motor-cars; and
     (b) 11 ft. in any part of the premises used by vehicles of any description other than private passenger motor-cars.
     (3) Where the length of any aerial line exceeds 2 chains the provisions of the Electrical Supply Regulations, 1927, shall apply.

110. Spans shall conform to the requirements of the Electrical Supply Regulations, 1927. When the span does not exceed 30 ft. soft-drawn copper conductors may be used.

111. Aerial lines shall be efficiently supported on insulators. Bobbin-insulators shall not be used for this purpose in places where they will be exposed to the weather.

112. Leading-in wires shall in no case be sweated on to hard-drawn wires where these latter are in tension, but shall, unless a mechanical connector is used, be sweated to the ends of the aerial lines away from that part in tension.

113. Each aerial circuit shall be run as a separate circuit from the main or distribution switchboard, and the leads of such circuit within a building shall be not less than 3/-029 in.

114. Aerial electric lighting, heating, or power wires shall not cross over or under in close proximity to any wireless aerial, or any stay-wire in connection therewith, or be erected in such a position that it is possible for them to make contact with a wireless aerial or stay-wire, or for any person to make simultaneous contact with any such wire and a wireless aerial or stay-wire.

CABLES.

115. (1) Conductors or their insulating-material, metallic sheathing, or conduit, whether earthed or not, shall not be in metallic contact with gas-pipes, telephone, bell, or other wires not forming part of the system nor shall they be placed at a less distance than 1 in. therefrom, except at crossings.
     (2) In the case of crossings, unless the inch clearance is provided, a non-conducting distance-piece shall be securely fixed between the two, and this distance-piece shall extend at least 1 in. in all directions at the crossing.

USE OF TWIN FLEXIBLE CORDS.

116. Twin flexible cords may be used for connection to lifts, subject to their being supported by porcelain insulators and to their being of such length that they will not come into contact with the bottom of the lift-well when the lift is at the lowest point of its run.
117. Flexible cords shall be installed in accordance with the requirements of Table XV in the Third Schedule hereto.
118. (1) Unarmoured flexible pendants shall be hung clear of shop fixtures or fittings, goods, and materials, and in no case shall flexible wiring support anything except the electrical fittings associated with it.
     (2) Flexible pendants shall not be used under verandas or doorways, or in any place exposed to the weather.
119. No flexible extension shall be taken more than 6 ft. across a ceiling to a drop-light. Such flexible shall be supported by an insulated hook fixed to the ceiling.
120. Flexible cords in shop-windows and show-cases shall be installed in strict accordance with these regulations.
121. The maximum weight carried by a twin twisted flexible cord shall be as follows:—

Number and Diameter of Wires comprising Conductor. Maximum Permissible Weight.
14/-0076 in. .. .. .. 3 lb.
23/-0076 in. .. .. .. 5 lb.
40/-0076 in. .. .. .. 10 lb.

EARTHED CONCENTRIC WIRING.

122. Earthed concentric wiring may be used only after approval has been given by—
     (a) The electrical supply authority where the supply is obtained from an Electric-power Board or other public body.
     (b) The Chief Electrical Engineer in any other case.
123. The use of earthed concentric wiring shall in all cases be subject to the following conditions:—
     (a) When the supply is derived from a supply authority’s mains it shall be taken from the secondary side of transformers or converters so arranged that the public supply system is electrically insulated therefrom.
     (b) Every earthed concentric installation shall be so arranged that the internal conductor is protected by a single-pole circuit-breaker or switch and fuse placed in a position easily accessible to the consumer and situated as near as possible to—
     (i.) The point or points of entry of the service main or to the secondary of the transformer, in the case of a public supply; or
     (ii) The generator in any other case.
     (c) Regulation 59 hereof shall apply to earthed concentric installations.
     (d) When the supply is direct current the external conductor shall always be the one nearest to earth potential and shall, where possible, be negative to the inner conductor; and the difference of potential between any two points in the external conductor shall not exceed—
     (i) Seven volts if the internal conductor is connected to the positive pole of the system; or
     (ii) One and a half volts if the internal conductor is connected to the negative pole of the system.