1634
THE NEW ZEALAND GAZETTE.
[No. 59

strength and be buried deeply enough to resist damage from
heavy traffic. Reasonable means shall be taken and periodi-
cal inspection made by the Corporation to prevent accumula-
tions of gas in those receptacles. Underground feeder-cables,
lead-covered and well armoured, may be laid direct in the
ground. The conductors of all underground cables shall be
well insulated from earth, and from each other in the case of
multiple conductor cables.

25. Where any underground electric line crosses or is in
    proximity to any metallic substance, special precautions shall
    be taken by the Corporation against the possibility of any
    electrical discharge to the metallic substance from the line,
    or from any metal conduit, pipe, or covering enclosing the
    line.

26. All metal conduits, pipes, or coverings containing any
    electric line shall be efficiently connected with earth, and
    shall be so jointed and connected up as to make good
    electrical connection throughout their whole length.

27. Where isolated lengths of metal conduit, pipe, or
    covering are used for the protection of any electric line at
    road-crossings or similar positions, special precautions shall
    be taken to prevent the possibility of any electrical charging
    thereof.

28. All metal pipes or casings containing any electric
    line shall be efficiently connected with earth, and shall be
    so jointed as to make good electrical connection throughout
    their whole length.

29. The Corporation shall be responsible for all electric
    lines, fittings, and apparatus belonging to them, or under
    their control, which may be upon a consumer’s premises,
    being maintained in a safe condition and in all respects fit
    for supplying energy.

30. In delivering the energy to a consumer’s terminals the
    Corporation shall exercise all due precautions so as to avoid
    risk of causing fire on the premises.

31. All electric lines and apparatus placed on a con-
    sumer’s premises shall be highly insulated, excepting such
    parts as are required to be connected with earth, and
    thoroughly protected against injury to the insulation or
    access of moisture, and any metal forming part of the
    electric circuit shall not, unless efficiently connected with
    earth, be exposed so that it can be touched. All electric
    lines shall be so fixed and protected as to prevent the possi-
    bility of electrical discharge to any adjacent metallic sub-
    stance.

32. Where the demand from the three-wire system does
    not exceed 2½ kilowatts the service mains for all installa-
    tions, whether of lighting (excepting arc-lighting) or power,
    shall consist of two conductors taken from one outer and the
    neutral wire.

33. Where the demand for lighting from the three-wire
    system exceeds 2½ kilowatts the main may consist of three
    conductors taken from the two outers and the middle wire,
    and where three conductors are used for the service mains
    the premises shall be wired with two circuits kept separate
    from each other, and the load shall be divided as nearly as
    possible equally between them.

34. The Corporation shall fix, where their service mains
    terminate on any premises, single-pole well-protected fuses
    on each conductor of at least 2½ in. clear break. Double-pole
    main switches shall also be fixed of ample carrying-capacity,
    well insulated, with quick break of sufficient clearance to pre-
    vent arcing. When the premises are wired for a consumption
    of 5 kilowatts or over, either from the two-wire system, or
    from one outer and the neutral wire or from both outer wires
    and the neutral wire of the three-wire system, the break
    switches should be fitted with magnetic blow-out or other
    equivalent device for extinguishing the arc, and a distance of
    at least 4 in. shall separate their poles. Where the supply is
    taken from the two outers and the middle wire two double-
    pole break switches shall be used, the neutral wire being
    joined to one terminal of each, and they shall be placed not
    less than 6 in. apart. They may be arranged to operate
    simultaneously.

35. All wiring shall be done from distributing-boards,
    which shall be of incombustible material. Suitable fuses
    on each pole fitted to engage in spring clips shall be placed
    on these boards, so that it shall be possible to disconnect any
    or all circuits from the supply.

36. The covers of fuses, switches, and plugs shall be of
    porcelain or other incombustible non-conducting material,
    or of rigid metal lined with vitreous enamel or suchlike
    substance. All metal parts liable to be touched must be
    effectively insulated from the electrical circuit. Where
    switchboards are accessible only to some responsible person,
    separate insulated covers for the parts mounted thereon will
    not be required.

37. There must be a porcelain bridge or other efficient in-
    sulation between the terminals of lamp-holders, and where
    lamp-holders are liable to be handled by persons making
    good earth contact they must be provided with non-con-
    ducting covers. Not more than ten sixteen-candle-power
    lamps, or their equivalent, shall be controlled by each switch.

38. The insulation-resistance of conductors used for the
    wiring of buildings for lighting or heating purposes shall not
    be less than 600 megohms per mile after one minute’s elec-
    trification and twenty-four hours’ immersion in water imme-
    diately preceding the test. Concentric conductors may be
    used, and their insulation-resistance shall not be less than
    that required for separate conductors.

39. All arc lamps shall be so guarded as to prevent pieces
    of ignited carbon or broken glass falling from them, and
    shall not be used in situations where there is any danger of
    the presence of explosive dust or gas.

40. Arc lamps used in any street for public lighting shall
    be so fixed as not to be in any part at a less height than
    10 ft. from the ground.

41. Arc lamps used in any street for private lighting shall
    be so fixed as not to be in any part at a less height than 8 ft.
    from the ground, and shall be so screened as to prevent risk
    of contact with persons.

42. Arc lamps must be insulated from earth, and fixed so
    that they cannot swing into contact with any substance,
    metallic or otherwise, that might connect them to earth.
    When supplied from the two outer wires of the three-
    wire supply system the conductors for supplying them
    with current, where not aerially suspended or run under-
    ground, shall be run in strong metal casing, which shall
    be electrically continuous and effectively connected with
    earth. The insulation resistance of such conductors run
    in metal casing shall, where the lamps are supplied from
    the outers of the three-wire system, be not less than 2,500
    megohms per mile after one minute’s electrification and
    twenty-four hours’ immersion in water immediately preced-
    ing the test; and where they are supplied at a pressure not
    exceeding 220 volts an insulation resistance of 600 megohms
    per mile will suffice. Resistances for the regulation of arc
    lamps shall be mounted on incombustible bases, shall be so
    placed that they cannot by conduction or radiation set fire
    to any contiguous materials, and shall be of ample size to
    safely carry the maximum current that will normally flow
    through them. Each arc-lamp circuit shall be provided with
    a switch and fuse on each pole.

43. Motors shall be either of the enclosed type or enclosed
    in strong metal cases, and shall be efficiently ventilated.
    Motors up to 3½-horse power may be supplied with current at
    220 volts, due regard being had to “balancing” and avoid-
    ance of disturbance to lighting.

44. The magnet, frame, and shaft of all motors shall be
    connected to an efficient earth by a copper conductor, cap-
    able of carrying without overheating twice the fusing-current
    of the main fuse with a minimum section of 7/8 standard wire
    gauge. All metal casings of switches, resistances, fuses,
    cables, and wires shall be efficiently earthed in a similar
    manner.

45. An approved starting switch and resistance shall be
    used on all motors connected directly with the mains, so
    arranged that the current can only be gradually increased.

46. Every motor must be controlled by an efficient double-
    pole quick-break switch suitable to prevent arcing, and con-
    veniently placed so that the person in charge of the motor
    can cut off wholly the supply from the motor, and all devices
    in connection therewith. This switch should interlock with
    the starting-switch so that while it can be operated to cut off
    the supply in any position of the starting-switch, it can only
    be closed when the starting-switch has been placed so as to
    put all the resistance in circuit.

47. A minimum-current cut-out must be provided to dis-
    connect the motor should the supply become interrupted.
    This arrangement may be in the starting-switch if found con-
    venient.

48. Efficient single-pole fuses or other automatic cut-out
    must be provided to efficiently protect the conductors on
    each pole from excess of current, and where these are used
    to guard conductors taking current only from the two outer
    wires of the three-wire supply system, provision shall be
    made to extinguish the arc.

49. Precaution shall be taken in choosing positions for and
    in setting up motors and the necessary devices in connection
    therewith so that there shall be no danger of fire being
    caused by their normal or abnormal action, or of shock being
    obtained in the ordinary handling thereof.

50. Brush rockers must be arranged so that they cannot
    bring either conductor into contact with the framework of
    the motor.

51. Terminals of motors must be guarded so that they
    cannot be accidentally touched or short-circuited.

52. Motors exceeding 3½-horse power must be supplied
    with current taken from the two outer wires of the three-
    wire system, and a distinct circuit must be run for them.
    The conductors must have an insulation-resistance of 2,500
    megohms per mile. For all motors supplied from the two-
    wire system, and for motors not exceeding 3½-horse power
    when supplied from one outer and the neutral wire, an in-
    sulation-resistance of 600 megohms per mile will suffice.

53. The conductors of all motors supplied from the outer