Download MEW E101 April 2013 (pdf, 280kb) - NSW Public Works

Part 2 - Switchboards and Associated Equipment
equipment shall be suitable for the actual fault let through energy and peak cut-off
current of the protective device corresponding to the indicated fault level.
Equipment shall not be used at a higher fault level than that for which it has been tested,
irrespective of fault duration.
203.2 Fault Current Limiting
Fault current limiting, either by fuses or suitable circuit breaker combinations shall only
be used where indicated and shall be of the form indicated.
Selection of fault current limiting equipment shall be in accordance with a selection table
accepted by the relevant Supply Authority.
203.3 Short Circuit Co-ordination
Type 2 short circuit co-ordination in accordance with AS 60947.4.1 is required for the
short circuit protective device, the motor contactor and the overload device if either of the
following conditions apply:
(a) Main busbar fault level of 31.5kA or greater at 415Volts has been specified.
(b) Starter size is greater than 37kW when direct on line started.
(c) Starter size is greater than 45kW when reduced voltage started.
Type 1 short circuit co-ordination in accordance with AS 60947.4.1 is required for the
short circuit protective device, the motor contactor and the overload device in all cases
other than (a), (b), and (c) above, except for the following condition:
Where ventilation fans are installed to provide a safe environment for personnel, Total
Co-ordination for the short circuit protective device, the motor contactor and the overload
in accordance with AS 60947.6.2 is required.
204 BUSBARS
204.1 Generally
Busbars for Proprietary Assemblies may be of the manufacturer's standard.
Multi-pole proprietary busbar assemblies for circuit breakers shall be of an accepted
type.
When busbar systems have been verified by type testing, such arrangements are
acceptable in lieu of the methods specified below.
Busbars shall be arranged to ensure that the phase sequence at all switchboard
equipment terminals is red, white and blue from left to right and from top to bottom, when
viewed from the front of the switchboard.
204.2 Material
Busbars shall be hard-drawn high-conductivity copper. Square-edged busbars shall not
be used.
204.3 Sizes
Busbar sizes in relation to current ratings shall be to AS 3000, assuming the
switchboards are of magnetic materials, located indoors in a well ventilated room and the
appropriate enclosure rating shall apply. However, smaller busbars may be used in
accordance with an approved Testing Authority Temperature Rise Test Certificate for a
switchboard with a similar internal physical configuration.
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MEW E101