EnergySafe Magazine Winter 2018, issue 51 - Page 18

18 For all the latest energy safety news visit www.esv.vic.gov.au 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 AS/NZS 4417.2:2012 Amendment 4 and Appendix B AS/NZS 3000:2018 Clause 7.3.2 AS/NZS 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 − www.esv.vic.gov.au/electrical-equipment-classes 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.