JULY 12.] THE NEW ZEALAND GAZETTE. 2407

boilers, steam-pipes, or other hot objects, or to risk of mechanical damage.

(2) All cables shall be installed in such a manner as will not damage or weaken the building unnecessarily, and with the least possible cutting-away of any structural work.

135. (1) The runs shall be selected to accord with the following requirements:—

(a) That no rubber-insulated cable shall be bent to a radius shorter than twice its overall diameter if unarmoured, or to a radius shorter than three times its overall diameter if lead-covered or armoured.

(b) That no paper-insulated cable (whether armoured or not) shall be bent to a radius shorter than six times its overall diameter.

(2) The foregoing represent the permanent bends; the arrangement of the runs must be such that the cable is not subjected to bends of this kind during drawing-in or erection.

BUNCHING OF CABLES.

136. When installed in wooden casing, cables carrying direct or alternating current may, if desired, be bunched, whatever their polarity or phase provided that—

(a) The number of cables bunched is not more than—

10 if the sectional area of each cable does not exceed 0·007 square inch (7/·036 in.);

6 if the sectional area of any cable exceeds 0·007 square inch (7/·036 in.), but does not exceed 0·0225 square inch (7/·064 in.);

4 if the sectional area of any cable exceeds 0·0225 square inch (7/·064 in.), but does not exceed 0·1 square inch (19/·083 in.);

3 if the sectional area of any cable exceeds 0·1 square inch (19/·083 in.).

(b) The size of the casing is sufficient to accommodate the cables without injury, but does not exceed that necessary to accommodate the maximum number of cables permissible.

137. (1) When installed in metal conduits cables carrying direct current may, if desired, be bunched, whatever their polarity; but if carrying alternating current the lead and return wires of a single-phase circuit, and all phase-wires with the neutral wire (if any) of a three-phase circuit, shall be bunched. All wires of several single-phase or three-phase circuits from the same source of supply may, if desired, be bunched.

(2) When cables are bunched, the number of cables so bunched and the run of conduit shall be such that it is possible to withdraw any one cable and draw in another of equal size in its place without injury.

(3) The number of cables installed in any one conduit shall not exceed that prescribed in Table XII in the Third Schedule hereto.

CABLE-SOCKETS AND OTHER CONNECTIONS.

138. The ends of all conductors having a sectional area greater than 0·01 square inch (7/·044 in.) shall be provided with a soldering-socket (preferably made in accordance with British Standard Specification No. 91) of such a size that all the strands of the conductor can enter the socket simultaneously, provided that where a binding-post is used the socket may be omitted.

139. Where a cable socket or terminal is used the cable shall be so supported that there is no appreciable stress on the socket or terminal.

140. Soldering-fluxes containing acid or other corrosive substances shall not be used.

141. When soldering or securing the ends of conductors to sockets or terminals the dielectric shall not be removed farther than is necessary to allow the conductor to enter and completely fill the socket or terminal and to be properly soldered. Dielectric damaged by the application of heat during the process of soldering shall be cut away, and shall be replaced with insulation equivalent to the original dielectric.

142. The braid, lead, or other covering over the dielectric, including the tape in contact therewith, shall be cut back at least ½ in. from the end of the dielectric.

143. In the case of paper-insulated cables the exposed conductor and dielectric shall be protected from moisture by being suitably sealed with insulating-compound.

144. The ends of stranded conductors unprovided with cable-sockets shall be made solid by soldering in the case of all conductors insulated with paper, and in the case of those insulated with rubber when the cables are fixed in damp situations. Where the strands are not soldered together they shall be taken under a washer of such size as will ensure full contact being made with all strands, or, alternatively, all strands shall be taken into a binding-post or terminal and there held by one or more suitable metal screws,

G

CONNECTION BETWEEN CABLES.

145. Subcircuit wiring of a smaller area than 0·0045 square inch (7/·029 in.) shall be carried out on the “loop-in” system. In all other cases the loop-in system shall be employed where practicable, and where not practicable connections between cables shall be made either by soldered joints or by mechanical connectors approved by the Chief Electrical Engineer.

146. Joints shall be readily accessible and mechanically and electrically sound. The conductors shall be soldered together, a flux free from acid or other corrosive substances being employed, and the resistance of the soldered joint shall be not greater than that of an equivalent length of the largest conductor included in the joint. In the case of rubber-insulated cables the joint shall be lapped with rubber to a thickness not less than that of the dielectric and with waterproofed protecting tapes so as to render it moisture-proof.

147. Every joint shall be enclosed in a joint-box complying with Regulation 149 hereof, the protective cover of the cable being maintained up to a point situated within that box. In the case of paper-insulated cables the joint, after being insulated with suitable impregnated tapes, shall be enclosed either in a joint-box or in a lead sleeve wiped on to the cable sheathings, the box or sleeve, as the case may be, being filled with an insulating-compound impervious to moisture.

148. Connections between cables and flexible cords shall in every case be made by means of a ceiling-rose or an “Era” or other connector approved by the Chief Electrical Engineer fixed within a suitable receptacle. In the case of heavy fittings which cannot be fixed by the above method, the proposed method of fixing shall be approved by the Authorized Inspector.

149. Joint-boxes shall be constructed wholly of durable, non-ignitable, non-absorbent materials, and all insulation shall be of permanently high electric strength and insulation resistance. The live parts shall be so arranged by suitable spacing or shielding with non-ignitable insulating-materials that conductors of opposite polarity or different phase cannot be readily short-circuited. If used in damp situations joint-boxes shall be weather and moisture resisting.

PART VI.—FITTINGS AND ACCESSORIES.

FITTINGS.

CONSTRUCTION OF FITTINGS.

150. Fittings shall be so designed and constructed that the passages for the insulated conductors are of ample size, and are free from rough projections and sharp angles or bends. All outlets shall have well-rounded edges or be bushed.

151. Fittings shall be so designed, and the insulated conductors so installed that no stress can be applied by the conductors to any terminal to which they may be connected.

152. Fittings shall be so designed and fixed that neither dust nor moisture can readily accumulate on live parts.

153. Where a hanging fitting exceeds 10 lb. in weight it shall be supported by a metal chain, tube, or rod, or by several flexible cords in such a manner that the maximum weight to which any cord is subjected shall be not greater than that specified in Regulation 121.

154. Open-type fittings shall not be furnished with inflammable shades unless such shades are kept free from contact with the lamps by suitable guards or supports. Celluloid shall not be used for shades or candle-tubes or in any situation near a lamp.

155. Enclosed-type fittings shall be provided with a removable glass receptacle arranged to enclose the lamp completely, and of such size or construction as to prevent undue heating of the lamp; and if the position of the fitting be such that the glass receptacle is liable to mechanical damage, the glass shall be protected by a suitable wire guard.

156. Fittings, whether fixed or portable, shall, wherever exposed to rain, drip, or externally condensed moisture, be of the weather-proof type.

ENCLOSED FITTINGS.

157. Enclosed fittings shall be used—

(a) In places where inflammable or explosive dust or gas is liable to be present or where inflammable goods are stored, and they shall be of strong construction, having airtight external globes of thick glass provided with substantial guards.

(b) In positions in which the lamp is either near to or can swing into contact with readily combustible materials.

PORTABLE FITTINGS AND APPLIANCES.

158. Every hand-lamp, except a hand-lamp made entirely of metal provided with a watertight glass and earthed as provided in Part XI hereof, shall have the metal parts of the holder and any metal in contact therewith shrouded by in-

or repaired, plugs and sockets shall be placed not less than 5 ft. above the floor-level unless an interlocked plug and gas-tight switch is used.

192. (1) Adapters for use in lamp-holders shall be constructed of tough non-ignitable, non-conducting, non-hygroscopic material other than hardwood.

(2) Adapters for use in screw holders shall be of one or other of the following types, namely—

(a) Combined adapter with pull-out plug;

(b) Adapter with a loose screw to prevent twisting of the flexible conductor.

ELECTRIC SIGNS.

193. Every electric sign shall comply with the following requirements:—

(a) It shall be readily accessible for inspection and attention.

(b) The sign shall be connected to the main supply by independent wiring, and shall be controlled by a fuse and switch on each live conductor. When more than one switch is required the switches shall be linked.

(c) Where elaborate switching and flashing apparatus is installed, a special non-ignitable enclosure shall be provided.

(d) If fixed in the open air—

(i) It shall be weather-proof, or, alternatively, the wiring and lamp-holders shall be weather-proof.

(ii) Only non-ignitable materials shall be used in its construction, except for letters and designs, for which hardwood is permissible.

(iii) All external wiring shall be of Class R, Class S, or Class T, as specified in Part III of the Second Schedule hereto, and in the case of Class T the conduits shall be galvanized.

(iv) External electric outline lighting, when the lamp-holders are not enclosed, or of the weather-proof type, shall be supplied at extra-low pressure.

terminal box.

(2) Trailing cables used in connection with portable motors shall have their protective sheathing terminating in and properly secured to the motor terminal box.

CONTROL OF MOTORS.

202. Every motor shall be controlled by a switch or circuit breaker suitably placed and so connected that the motor and all apparatus in connection therewith may be isolated from the supply: Provided that in the case of supply from a system having a multiple earthed neutral, it shall not be necessary to disconnect the neutral.

203. (1) Every motor shall be provided with an efficient switch or circuit-breaker for starting and stopping, so placed as to be easily operated by the person controlling the motor, and every motor having a rating exceeding ½ horse-power for direct current, or 3 horse-power for alternating current, shall in addition be provided with—

(a) Means for automatically opening the circuit if the supply-pressure falls sufficiently to cause the motor to stop:

(b) In the case of direct-current motors, a starter or switch for limiting the amount of current taken when starting and accelerating:

(c) In the case of alternating-current motors, a starter or switch which shall limit the amount of current taken, when starting and accelerating, to the value (if any) required by the electrical supply authority:

(2) Every motor rated at over 3 horse-power shall be provided with an approved time-lag automatic over-load release in addition to the low-voltage release.

204. (1) Motors of 3 horse-power or under shall, when the starting-current is over 200 per cent. of full-load current, be provided with time-lag cut-outs or automatic time-lag release approved by the Authorized Inspector, in addition to the