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15 BUSBAR TRUNKING SYSTEMS (BUSWAYS), INCLUDING RISING MAINS SYSTEMS

15 BUSBAR TRUNKING SYSTEMS (BUSWAYS), INCLUDING RISING MAINS SYSTEMS

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AS/NZS 3000:2000

SECTION 4
APPLIANCES

112

INSTALLATION OF
AND ACCESSORIES

4.1 GENERAL

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The requirements of this Section apply to the selection and
installation of appliances, accessories and other electrical equipment
not covered in other Sections, to determine their compliance with
Section 1. The requirements relate to the following:
(a)

Protection against physical injury.

(b)

Protection from thermal effects.

(c)

Methods of connection to the electrical installation.

(d)

External influences and environmental conditions.

(e)

Adverse effects on the electrical installation and the supply.

(f)

Isolation and switching devices.

(g)

Protective devices.

(h)

Special electrical installations for particular electrical equipment.

4.2 ELECTRICAL EQUIPMENT REQUIRING PROTECTION AGAINST
INJURY FROM MECHANICAL MOVEMENT
4.2.1 Rotating machines (motors)
4.2.1.1 Devices for isolation and switching
Electric motors shall be provided with suitable devices for starting
and stopping, placed so as to be easily operated by the person in
charge of the motor. In the event of a fault in a motor control circuit,
the stopping device shall remain effective.
Arrangements for emergency stopping of motors shall comply with
Clause 2.8.5.
In the case of electrical equipment that is remotely controlled, devices shall
be provided for stopping the motors at all points where danger is likely to
occur.
4.2.1.2 Protection against restarting or reversal
Each electric motor shall be provided with a means to prevent automatic
restarting after stopping due to a drop in voltage or the failure of the supply,
where unexpected restarting of the motor might cause danger.
Where safety might be impaired by incorrect direction of rotation of a motor,
suitable measures shall be taken to prevent danger from reversal of the
direction of rotation.
NOTE: This applies particularly where reverse-current braking is used.

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4.3 ELECTRICAL EQUIPMENT REQUIRING PROTECTION AGAINST
THERMAL EFFECTS
4.3.1 General
The selection and installation of electrical equipment shall be such
that the temperature characteristics of the electrical equipment,
properly installed and operated, do not adversely affect the electrical
equipment or the electrical installation itself, or any other installation,
whether electrical or not.
Adequate ventilation shall be provided where heat is generated in normal
operation, in order to maintain operating temperatures below the rated or
specified limits.
NOTE: Account should be taken of the influence that temperature might have on
the operational or characteristic values of the electrical equipment.

4.3.2 Prevention of fire hazard

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4.3.2.1 Installation of electrical equipment
Electrical equipment shall not be installed in a position where it might cause
a fire hazard.
Manufacturers’ installation instructions shall be observed in addition to the
requirements of this Clause 4.3.2.
4.3.2.2 Storage of flammable materials
Where there is a likelihood that an area will be used to store flammable
materials, measures shall be taken to prevent ignition of such materials by
sparks or high temperature sources.
NOTE: See Clause 7.9 for requirements for hazardous areas.

4.3.2.3 High surface temperatures
Where fixed electrical equipment could attain surface temperatures that
would cause a fire hazard to adjacent materials, the electrical equipment
shall be —
(a)

mounted on or within materials that will withstand such temperatures
and are of low thermal conductance; or

(b)

screened from elements of building construction by materials that will
withstand such temperatures and are of low thermal conductance; or

(c)

mounted at a sufficient distance from any material on which such
temperatures could have deleterious thermal effects, any means of
support being of low thermal conductance, so as to allow safe
dissipation of heat.

NOTES:
1 Tungsten filament lamps, ELV halogen lamps, radiant heaters and infra-red
lamps are examples of high temperature sources.
2 Restriction of heat dissipation from electrical equipment can result in high
temperatures in the electrical equipment itself.
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Fixed electrical equipment causing a focussing or concentration of heat
shall be at a sufficient distance from any fixed object or building element so
that the object or element, in normal conditions, cannot be subjected to a
dangerous temperature.
4.3.2.4 Emission of arcs or sparks
Where arcs or sparks might be emitted by permanently connected electrical
equipment in normal service, the electrical equipment shall be —
(a)

totally enclosed in arc-resistant material; or

(b)

screened by arc-resistant material from building elements on which the
arcs could have deleterious thermal effects; or

(c)

mounted at a sufficient distance from building elements on which the
arcs or sparks could have deleterious thermal effects, to allow safe
extinction of the arcs or sparks.

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4.3.2.5 Electrical equipment enclosures
The materials of enclosures of electrical equipment shall withstand the
highest temperature likely to be produced by the electrical equipment.
Flammable or readily combustible materials shall not be used for the
construction of enclosures.
4.3.3 Protection against burns
Except for electrical equipment which complies with appropriate Standards
which specify a limiting temperature, an accessible part of electrical
equipment within arm’s reach shall not attain a temperature in excess of the
appropriate limit stated in Table 4.1. Each such part of the electrical
installation likely to attain under normal load conditions, even for a short
period, a temperature exceeding the appropriate limit in Table 4.1 shall be
guarded so as to prevent accidental contact.
NOTE: This requirement does not apply to items such as lamps.

TABLE 4.1
TEMPERATURE LIMITS IN NORMAL SERVICE FOR
PARTS OF ELECTRICAL EQUIPMENT WITHIN ARM'S REACH
Accessible part
Hand-held means of
operation
Parts intended to be
touched but not hand
held
Parts which need not be
touched for normal
operation

Material of
accessible
surface

Maximum temperature
°C

Metallic

55

Non-metallic

65

Metallic

70

Non-metallic

80

Metallic

80

Non-metallic

90

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4.3.4 Motors
4.3.4.1 Protection against overload
Unless incorporated in an item of electrical equipment that complies with an
appropriate Standard, each electric motor having a rating exceeding
0.37 kW shall be provided with control equipment incorporating means of
protection against overload of the motor.
4.3.4.2 Protection against overtemperature
4.3.4.2.1 General
Except where not required in accordance with Clause 4.3.4.2.2,
overtemperature protective devices complying with Clause 4.3.4.2.3 shall
be provided for —

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(a)

(b)

motors that may be required to run unattended (see Note) and which
have a rating greater than —
(i)

for shaded-pole type motors ....... 480 V.A; or

(ii)

for other unattended motors ....... 240 V.A; or

other types of motors which have a rating greater than 2.25 kW.

NOTE: A continuously running motor or a motor under automatic control in a
non-domestic premises, where no person is normally in attendance in the
vicinity of the motor, is deemed to be unattended. Consideration should be
given to the presence of a caretaker, or other person who may be responsible
for the inspection of motors, in which case it may be appropriate not to regard
motors as unattended.
Examples of unattended motors are as follows:
(i) Motors that drive refrigerators in shops.
(ii) Motors that are in a remote portion of a building, such as a drainage sump
in a basement.
(iii) Motors that drive a communal refrigerator in a block of flats.

4.3.4.2.2 Protection not required
Overtemperature protection shall not be provided —
(a)

for motors associated with emergency systems in accordance with
Clause 7.10.9.3; or

(b)

where the opening of the motor circuit could create a hazard.

Overtemperature protection need not be provided for unattended
submersible pump motors, immersed in water, which have a rating not
greater than 2.25 kW.
4.3.4.2.3 Overtemperature protective devices
Overtemperature protective devices shall comply with the following:
(a)

Protection Protection of motor windings against excessive
temperatures shall be provided by thermal-overload protective devices
complying with AS 1023.1 or by a device which affords an equivalent
degree of protection.
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(b)

(c)

116

Operation The protective device shall disconnect, directly or
indirectly, not less than the following number of supply conductors to
the motor:
(i)

For d.c. motors supplied from a two-wire supply with one line
earthed and single-phase a.c. motors ................................... one.

(ii)

For d.c. motors supplied from two unearthed lines and threephase a.c. motors ................................................................ two.

Additional requirements for unattended motors Where thermal
protective devices for unattended motors are of the automatic reset
type, the device shall protect the motor windings against attaining
excessive temperatures under continued tripping conditions.

4.3.5 Room heaters

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4.3.5.1 General
Where a permanently connected room heater or a number
permanently connected room heaters are installed in one room
individual functional switch, in accordance with Clause 2.8.6, and
individual isolating switch, in accordance with Clause 2.8.3, shall
provided for each room heater or for each group of room heaters.

of
an
an
be

4.3.5.2 Functional switch
The functional switch shall be installed in a readily accessible position in
the same room or immediately adjacent to an entrance to the room in which
the heater or heaters are located.
The functional switch may be —
(a)

a switch with an ‘off’ position incorporated with the room heater; or

(b)

an isolating switch provided in accordance with Clause 4.3.5.3(a).

4.3.5.3 Isolating switch
The isolating switch shall be —
(a)

installed in the room or immediately adjacent to an entrance to the
room where the room heater is located; or
NOTE: The switch may be incorporated in a temperature control device
provided that it has a definite ‘off’ position.

(b)

installed on the switchboard at which the room heater final subcircuit
originates.

Where a number of permanently connected room heaters are installed in
one room and are supplied by the one final subcircuit, a single isolating
switch may be used for the room heaters.

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4.3.6 Lighting equipment and accessories
4.3.6.1 Luminaires
Luminaires and their associated ancillary gear shall be so installed as
not to cause undue temperature rise, deterioration or ignition of the
materials on which they are mounted.
NOTES:
1 Account should be taken of the highest rating of the lamp likely to be used.
2 Attention is drawn to the high temperatures that can be generated in
luminaires. Cables with suitable insulation temperature ratings should be
selected.

Luminaires shall be suitable for the highest temperatures to which they are
likely to be subjected by external influences.
4.3.6.2 Lamps near flammable materials

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Every lamp that is near flammable material shall be suitably shielded by a
shade, reflector, guard or enclosure.
Flammable shades shall not be installed where they are liable to come in
contact with any lamp.
A1

The distance separating incandescent lamps of spotlights and objects,
illuminated by them, which are made of flammable material shall be not less
than the following values:
Rating watts

> 100
> 300

Minimum
distance
m

≤ 100
≤ 300

0.6
1.0
1.8

NOTE: Attention should be given to the need for adequate ventilation where
extra-low voltage (e.g. 12 V) spotlights are used. Installers should also note that
the values of current at ELV can be very high (as much as twenty times higher
than those at normal low voltage (230/240 V)) and the wiring needs to be rated
accordingly.

4.3.6.3 Lamps and luminaires near thermal insulating material
Thermal insulating material shall not prevent free air flow around or through
luminaires and their associated ancillary gear, and shall be separated by
not less than —
(a)

25 mm from low voltage lamps or luminaires; or

(b)

50 mm from extra-low voltage dichroic lamps or luminaires or
associated transformers.

Where the thermal insulation is of the loose fill type, fire resistant barriers
shall be provided to maintain the separation.
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4.3.7 Electric duct heaters
The electrical portion of any electric duct heater installation shall comply
with the requirements of this Standard.
NOTE: Attention is drawn to the fact that —
(a) such installations are within the scope of AS/NZS 1668.1; and
(b) safety requirements are contained in AS 3102; and
(c) compliance therewith may be required by the relevant
authorities.

regulatory

4.3.8 Electric heating cable systems
4.3.8.1 General
Cables for electric heating systems shall be of a type specifically designed
for the purpose. The heating equipment shall be installed in accordance
with the manufacturer’s instructions.
4.3.8.2 Heating cables

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Heating cables shall be so installed that they —
(a)

are not in contact with flammable materials; and

(b)

are completely and adequately embedded in the substance they are
intended to heat; and

(c)

do not suffer any detrimental effect due to flexing or movement of the
substance in which they are embedded.

4.3.8.3 Functional switch
Cables or groups of cables that comprise the heating system shall be
provided with an individual functional switch in accordance with
Clause 2.8.6.
Where the heating system is provided for floor warming the functional
switch shall be installed in a readily accessible position in the room or area,
or immediately adjacent to an entrance to the room or area, in which the
heating system is located.
The functional switch may be an isolating switch provided in accordance
with Clause 4.3.8.4(a).
4.3.8.4 Isolating switch
Cables or groups of cables that comprise the heating system shall be
provided with an isolating switch in accordance with Clause 2.8.3.
Where the heating system is provided for floor warming the isolating switch
shall be installed —
(a)

in the room or area, or immediately adjacent to an entrance to the
room or area, in which the heating system is located; or
NOTE: The switch may be incorporated in a temperature control device
provided that it has a definite ‘off’ position.

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AS/NZS 3000:2000

on the switchboard at which the heating system final subcircuit
originates.

4.3.8.5 Additional protection
Where heating cables or tapes are not provided with double insulation, or
equivalent, they shall be —
(a)

provided with adequate mechanical protection to prevent damage; or

(b)

provided with an earthed metallic armouring, screen, covering or
enclosure; or

(c)

protected by an RCD with a maximum rated residual current of 30 mA.

4.3.8.6 Signs

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Where heating cables are installed suitable signs drawing attention to their
existence shall be provided in each location. Signs warning of the danger of
covering embedded heating equipment with furnishings or building
materials that might cause excessive temperatures, shall be provided,
where appropriate.
4.3.9 Appliances producing hot water or steam
4.3.9.1 General
All appliances producing hot water or steam shall be protected by
design or installation against overheating in all service conditions.
Unless the appliances comply as a whole with an appropriate
Standard, the protection shall be by means of an appropriate non-selfresetting device, functioning independently of the thermostat.
If an appliance has no free outlet, it shall also be provided with a
device that limits the water pressure.
4.3.9.2 Water heaters
4.3.9.2.1 Access
Every unvented water heater shall be installed so that the following
are readily available for operation, inspection and adjustment:
(a)

Easing equipment of pressure-relief devices.

(b)

All terminals of the protective devices.

NOTE: An unvented water heater is one which is intended to operate at the
pressure of the water system and the flow of the water being controlled by one
or more valves in the outlet system.

4.3.9.2.2 Operation of protective devices
Overtemperature cutouts and similar protective devices fitted to unvented
water heaters shall —
(a)

operate directly in the circuit wiring to the heater elements; and

(b)

not be arranged for control through relays or contactors.

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4.3.9.2.3 Isolating switch
Every water heater shall be provided with an independent isolating switch
or switches in accordance with Clause 2.8.3. Such switch or switches shall
be —
(a)

additional to any automatic switch incorporated in the heater structure;
and

(b)

grouped together; and

(c)

installed on or adjacent to the water heater or on the switchboard at
which the water heater final subcircuit originates.

4.3.9.3 Electrode-type boilers (including steam generators and water
heaters having electrode elements)
Electrode-type boilers shall be installed only with the permission of the
electricity distributor and shall comply with any requirements of the
electricity distributor.

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4.3.10 Electrical equipment containing liquid dielectrics
4.3.10.1 General
Wherever electrical equipment such as oil-filled transformers or capacitors
contains flammable liquid in significant quantity, precautions shall be taken
to prevent burning liquid and the products of combustion of the liquid
(flame, smoke, toxic gases) spreading to other parts of the premises.
4.3.10.2 Liquid dielectrics having a flashpoint not exceeding 250 °C
Where electrical equipment is filled with a liquid dielectric having a
flashpoint not exceeding 250°C and has a total liquid capacity exceeding
50 L in any unit or group of adjacent units, precautions shall be taken to
prevent the spread of fire.
Such precautions may include the provision of enclosures consisting of fireresisting dikes, bunds, curbed areas, basins, trenches filled with coarse
crushed stone or, where necessary, trapped drains.
NOTES:
1 Examples of such precautions are —
(a) a drainage pit to collect leakages of liquid and ensure their extinction in
the event of fire; or
(b) installation of the electrical equipment in a chamber of adequate fire
resistance and the provision of sills or other means of preventing
burning liquid spreading to other parts of the premises, such chamber
being ventilated solely to the external atmosphere.
2 For less than 50 L, it is generally sufficient to take precautions to prevent the
escape of liquid.
3 It may be desirable to switch off the supply to the electrical equipment
automatically at the onset of a fire.

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4.3.11 Cooking appliances
A circuit for a fixed or stationary cooking appliance shall be provided
with a functional switch, in accordance with Clause 2.8.6, mounted
near the appliance in an accessible position.
NOTE: The switch should be mounted within 2 m of the hob in such a position
that the user does not have to reach across the hob.

A single switch is permissible for the control of associated cooking
appliances, such as a split-level range combination, in the same room.
4.4 ELECTRICAL EQUIPMENT REQUIRING PROTECTION AGAINST
EXPLOSION
The design, construction and installation of electrical equipment
requiring protection against explosion in gas and dust atmospheres
(hazardous areas) shall be in accordance with the appropriate parts of
AS 2381 and Clause 7.9.

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4.5 TRANSFORMERS
4.5.1 General
Transformers shall be installed in accordance with Clauses 4.5.2 to
4.5.5.
The requirement need not apply to the following:
(a)

An instrument transformer.

(b)

An extra-low voltage transformer.

(c)

A luminous discharge tube transformer.

(d)

A transformer incorporated in a motor starter or other similar electrical
equipment.

4.5.2 Secondary circuit
4.5.2.1 General
The wiring and electrical equipment connected to the secondary winding of
a transformer shall comply with the requirements of this Standard for extralow, low or high voltage, as appropriate to the nominal secondary voltage.
4.5.2.2 Control and protection
Except where the conditions set out in Items (i) and (ii) apply, the
conductors connected to the secondary windings of the transformer shall
be —
(a)

considered as submain or final subcircuit conductors, as appropriate;
and

(b)

protected and controlled in accordance
requirements of Clauses 2.4 and 2.8.

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the

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AS/NZS 3000:2000

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The requirements for separate over-current protection of the secondary
circuit conductors need not apply where —

A1

(i)

the transformer secondary winding supplies only one submain or final
subcircuit; and

(ii)

the secondary circuit conductors have a current-carrying capacity not
less than the rated load current of the transformer primary winding
multiplied by the ratio of the transformer primary voltage to the
secondary voltage.

4.5.3 Low voltage transformer supply
4.5.3.1 Isolating transformers
Electrical equipment may be connected to an isolating transformer in
accordance with Clause 1.7.4.5.
4.5.3.2 Other transformers

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Where the low voltage transformer output does not comply with
AS/NZS 3108, the electrical equipment shall be earthed as required by
Clause 5.4.
4.5.4 Autotransformers
The output circuit of an autotransformer shall be insulated for the highest
input or output voltage of the autotransformer.
4.5.5 Step-up transformers
Where a transformer is used to raise the voltage above that at which
electricity is supplied at the point of supply, no connection, other than that
made by an earthing conductor, shall be made between the primary and
secondary windings.
4.6 CAPACITORS
4.6.1 General
The requirements of this Standard do not apply to capacitors that are fitted
as an integral part of other electrical equipment such as luminaires.
4.6.2 Electrical equipment
4.6.2.1 General
Electrical equipment and wiring for connection to capacitors shall be
suitable for the highest voltages, currents and temperatures that are likely
to occur.
Adequate means shall be provided to ensure the dissipation of heat from
the electrical equipment.
4.6.2.2 Rating of circuit-breakers, switches, or contactors
Any circuit-breaker, switch or contactor controlling a capacitor shall be
suitable for the purpose of switching capacitors and shall be of appropriate
rating.
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