EnergySafe Magazine Spring 2017, issue 48 | Page 10

10
Electrical
Q&A

Your electrical
questions
answered!
Compiled by ESV’s Electricity Technical
Advisor, John Stolk
EnergySafe continues its regular series
featuring some of the questions that
ESV receives on a range of electricity
installation issues, some of them relating
to gas installations. Also provided are the
answers together with references to the
Acts, Standards, Regulations
and Clauses that apply to them.
Question Answer Standard Clause
Can someone tell me the clause
number for cables to be clipped
every 300mm? The Wiring Rules do not specify a set distance between supports,
but requires cables to be installed to minimise damage to the
sheathing and insulation with the provision of supports, continuous
or at appropriate intervals suitable for the mass of the cable. AS/NZS
3000:2007 Clause 3.9.3
Does an outbuilding (i.e a shed 3m
away from the main building) always
require a distribution board? No, there is no requirement for an outbuilding to have
a sub board installed. AS/NZS
3000:2007 Clause 2.3.4.1
(a)(i) and (ii)
AS/NZS
3000:2007 Clause 2.5.3
AS/NZS
3000:2007 Clause 1.5.11.2
and 3.9.8
I would put one in regardless but
clause 2.3.4.1(b)(i) seems to imply
it is not necessarily.
Clause 2.3.4.1 of AS/NZS 3000:2007 specifies the
requirements if a switchboard is installed.
Hey guys, I’m trying to find a clause
number that specifically states ovens/
cooking appliances have to be on their
own dedicated circuit. Can anyone
help or point me in the right direction? The Wiring Rules do not specify that a cooking appliance
requires to be installed on its own dedicated circuit.
The manufacturer could have that requirement within
their installation instructions.
Boys having a discussion at work
regarding RCDs. One is of the opinion
that the minimum size that can feed
a 40A RCD is 6mm. The other is
saying the cable size is depending
on maximum demand of the circuit
breakers being feed by that 40a RCD. The cable supplying an RCD shall have a current carrying capacity
not less than the maximum current rating of the RCD.
When an air cooling unit is added to
an existing gas fired Hydronic ducted
heating unit (i.e. Air Smart system),
does the electrical supply to both units
have to be altered to comply with the
isolation requirements similar to
a split air-conditioning systems? Yes. Air-conditioning systems incorporating a compressor
shall be provided with a lockable isolating switch installed
adjacent to the unit, which isolates all parts of the system
including ancillary equipment, from the same location.
Where the manufacturer requires a part of the system
to be connected by a plug and socket at the internal unit,
the isolating switch installed at the external unit shall
control the socket outlet supplying the internal unit.
The cable supplying a 40 amp RCD can have a current carrying
capacity of less than 40 amps if:-
» » overload protection device supplying the RCD is less
than 40 amps, or
» » overload protection devices on the load side of the RCD
total less than 40 amps
» » the current carrying capacity of the conductor may
be sized to the overload production.