2556

THE NEW ZEALAND GAZETTE.

[No. 65

45-43. No portable appliance shall be used in any situation where inflammable or explosive dust or gas is liable to be present unless such appliance has been previously approved for the particular place.

45-44. Switches, cut-outs, and all other accessories liable to arc shall, where practicable, be located outside such places as aforesaid, but where this is impracticable they shall be of the metal-clad type, and where inflammable or explosive dust or gas is liable to be present they shall be flame-proof. All flame-proof enclosures shall comply with British Standard Specification No. 229 or its equivalent.

45-45. Every switch used to control any lamp or appliance in any place where inflammable or explosive dust or gas is liable to be present shall be of the single-throw tumbler or other indicating type.

45-46. Where inflammable or explosive dust or gas is liable to be present all generators, motors, starters, and their terminals shall be flame-proof in accordance with British Standard Specification No. 229 or its equivalent.

45-47. No conductors other than those required for the supply and use of current therein shall be installed in any place where inflammable goods are stored or packed or where inflammable or explosive dust or gas is liable to be present.

45-48. The wiring for lamps, appliances, and motors attached to apparatus used to convey or deliver a highly inflammable liquid—e.g., petrol—shall comply with the following requirements:—

(a) Where the apparatus is exposed to the weather the wiring shall be connected to a separate subcircuit.

(b) The conduit within the casing of the apparatus shall be rendered gas-tight.

(c) Where underground conductors are used they shall terminate in a gas-tight plug-socket rigidly fixed between 2 in. and 4 in. above the level of the base flange of the casing of the apparatus. The conductors from the lamp-holders to the plug-socket shall be enclosed in rigid conduit as far as practicable and then in gas-tight flexible conduit, and shall terminate in a gas-tight plug.

(d) Where overhead conductors are used and the apparatus is exposed to the weather the conductors from the switchboard shall terminate in a weatherproof plug-socket fixed not less than 7 ft. above ground-level. The conductors from the lamp-holders to the plug-socket shall be enclosed in rigid conduit within the apparatus, over the space between the apparatus and the building and for an additional distance of not less than 1 ft., and such conduit shall be rigidly fixed to the apparatus and to the building. The conductors between the rigid conduit and the plug-socket shall be enclosed in watertight flexible conduit and shall terminate in a weatherproof plug.

(e) Where the conductors are not underground and the apparatus is not exposed to the weather the conductors from the switchboard shall terminate in a gas-tight plug-socket fixed in a permanent position as near as practicable to the lamp-holders on the apparatus. The conductors from the lamp-holders to the plug-socket shall be enclosed in rigid conduit within the apparatus and may be so enclosed outside the apparatus provided the conduit is properly supported. The conductors between the rigid conduit and the plug-socket shall be enclosed in gas-tight flexible conduit and shall terminate in a gas-tight plug.

(f) In those cases where the lighting fittings have to be moved when cleaning the liquid container:—

(i) A gas-tight plug and socket shall be fixed near such fittings in such a position and so connected that the whole top part of the conduit, together with the lighting fittings and wiring, may be removed bodily after withdrawing the plug; or

(ii) In those cases where the conductors to the lighting fittings are of flexible cord protected with tough rubber compound in accordance with Regulation 23-71 hereof, a gas-tight union may be fitted in the vertical part of the conduit so installed as to permit the whole of the top part of the conduit, together with the lighting fittings and wiring, to be rotated horizontally not more than 90°.

WIRING WHERE CORROSIVE GAS, FUMES, OR LIQUIDS ARE PRESENT.

45-51. Where any corrosive gas, fume, and/or liquid is present, or liable to be present, the proposed system of wiring shall be submitted to the Chief Electrical Engineer for approval, and no wiring shall be installed or used except in accordance with such approval.

45-52. Conduit and its fittings, saddles, and fixings in such places as aforesaid shall be of incorrodible material or rendered incorrodible by a suitable method.

45-53. Conduit fittings and boxes in such places as aforesaid shall be rendered watertight.

WIRING IN FREEZING-CHAMBERS AND COOLING-CHAMBERS.

45-61. No switchboard shall be fixed in any freezing-chamber or cooling-chamber.

45-62. No switch shall be fixed in any freezing-chamber or cooling-chamber, except on an alarm circuit, in which case only switches approved for the purpose may be used.

45-63. Every switch for any freezing-chamber or cooling-chamber shall be double-pole, except in the case of multiple-earthed neutral systems and alarm circuits.

45-64. No conductors other than those required for the supply and use of current therein shall be installed in any freezing-chamber or cooling-chamber.

WIRING FOR EXPERIMENTAL AND DEMONSTRATION PURPOSES.

45-71. Where any wiring is used in connecting up any apparatus for experimental, testing, demonstration, or research purposes in electrical engineering workshops, test-rooms, and the like where qualified persons are in charge, such wiring shall comply as far as practicable with the requirements of these regulations so as to reduce any electrical hazard to a minimum. Adequate switching arrangements shall be provided so that live terminals and connections need not be handled and adequate protective apparatus shall be provided to take care of short-circuits or overload. Notices warning persons against the danger of touching live metal shall be prominently displayed.

OUTDOOR LIGHTING.

45-81. When the lamp-holders or fittings for outdoor lighting and the subcircuit conductors are attached to messenger wires the work shall comply with the following requirements:—

(a) The messenger wire shall be of galvanized steel or copper of adequate strength to the satisfaction of the Authorized Inspector; and

(b) The subcircuit conductors shall be attached to the messenger wire by means of outdoor type insulators spaced at intervals of not more than 4 ft.; and

(c) The subcircuit conductors shall be of stranded copper of a cross-sectional area not less than 0·003 sq. in. (3/036 in. or its equivalent) and may be soft-drawn; and

(d) The subcircuit conductors, other than a multiple-earthed neutral conductor, shall be covered with vulcanized-rubber in accordance with Regulation 23-12 hereof.

45-82. Where no messenger wire is used and where the subcircuit conductors for outdoor lighting are used to support the fittings such conductors shall, in addition to complying with paragraph (d) of the last preceding regulation, be of hard-drawn stranded copper of adequate strength to the satisfaction of the Authorized Inspector, but in no case shall the cross-sectional area be less than 0·01 sq. in. (7/044 in. or its equivalent).

BELL AND OTHER EXTRA-LOW PRESSURE CIRCUITS.

45-91. No cable or flexible cord used for lighting, heating, or power shall be installed in the same casing or conduit as any cable or flexible cord used for an electric bell, telephone, signalling apparatus, and the like.

45-92. A bell circuit and/or a signalling circuit (except a telephone circuit) may be operated from any subcircuit which is connected to a service-main, provided that such bell or signalling circuit is connected to the secondary side of a double-wound transformer, having a secondary voltage not exceeding 30 volts, and provided further that—

(a) Each such transformer is protected on the primary side by a single-pole cut-out; and

(b) The conductors of such bell or signalling circuit where unenclosed are secured by means of insulated staples, and that where subject to mechanical injury such conductors are adequately protected; and

(c) Joints in the conductors of such bell or signalling circuit are, as far as practicable, avoided; and

(d) The conductors of such bell or signalling circuit are insulated with vulcanized-rubber of not less than 300 megohm grade, save that ordinary bell wire may be used provided that the secondary voltage does not exceed 12 volts and that the transformers comply with Regulation 21-15 hereof.

45-93. Electric toys may be operated from any subcircuit which is connected to a service-main provided that they are connected to the secondary side of double-wound transformers which comply with Regulation 21-16 hereof.