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Question Answer Standard Clause
I have in stock a number of DC
isolators I typical use for PV solar
systems. No. You cannot install (supply) these isolators. Electricity Safety
Act 1998 Section 57
4417.2:2012 Amendment 4
3000:2018 Clause 7.3.2
4777.1:2016 Clause 3.3.3
I note that they are not on the ERAC
list of approved DC isolators. I bought
these sometime before 30 June 2018.
Can I still install these isolators?
It is an offence under section 57 of the Electricity Safety Act 1998
to supply Level 3 or prescribed electrical equipment without being
approved by ESV, another electrical safety state regulator or
JAS-ANZ accredited third-party certifier.
Amendment 4 of AS/NZS 4417.2:2012 was published on
June 30 2017. Amendment 4 introduced nine additions to
the prescribed electrical equipment categories – one of these
additions was DC isolators.
Appendix B of AS/NZS 4417.2 lists all of the prescribed
electrical equipment categories.
This list is available on the ESV website −
Do I need to make sure the voltage
rise on the inverter energy system
circuit is less than 2%?
AS/NZS3000 says that I can have
a 5% voltage drop.
Yes. Clause 7.3.2 of the 2018 Wiring Rules states inverter energy
systems shall comply with AS/NZS 4777 series.
Clause 3.3.3 of AS/NZS 4777.1 stipulates the requirement that
the voltage rise from the output terminals of the inverter to the point
of supply for the electrical installation shall be less than 2%.
A 3kVA inverter outputs approx. 13A. So, depending on the way
the cable is installed and taking into account de-rating factors,
a 2.5mm cable can carry that amount of current.
To keep the voltage rise below 2%, you are limited to the length
of the cable run. The other issue is the voltage rise that occurs
on the mains cable, and more importantly, the sub-mains cable.
If the inverter is connected to a distribution board, the voltage rise
of the sub-mains cable also needs to be calculated. In some cases,
an IES cannot be installed on the distribution board without an
upgrade to the sub-mains.
Note: Check this before you start installing the system as it can
be an expensive upgrade to do once installation is complete.