The requirement for DC isolators to be certified, where they are incorporated in inverters complying with AS/NZS 4777.2:2020 has been extended until 30 June 2022.
The Electrical Safety Office (ESO) acknowledges the challenges manufacturers and suppliers are having with getting their DC isolators, including those installed within inverters, certified to AS 60947.3 due to the current status of approved test labs with accreditation to carry out the required tests.
From 19 December 2021, ESO will require all inverters installed in premises located in Queensland to comply with AS/NZS 4777.2:2020 (including the requirement that an inverter's integrated DC isolators comply with AS 60947.3:2018) but will allow suppliers/manufacturers until 30 June 2022 to achieve certification of those DC isolators to AS 60947.3.
During this period, inverters complying to AS/NZS 4777.2:2020 will not be prevented from being sold, even if the DC isolator within the inverter is not certified, unless specific safety issues are identified.
Installers of solar PV inverters incorporating DC isolators can rely on the supplier declaration of compliance to AS/NZS 4777.2:2020 as evidence the inverter can be installed in accordance with AS/NZS 3000 The Wiring Rules and AS/NZS 5033 Installation and safety requirements for photovoltaic (PV) arrays.
Grid connected inverters are required to meet the Australian standard AS/NZS 4777.2 Grid connection of energy systems via inverters, Part 2: Inverter requirements. This is the product standard for inverters used to connect solar panels and battery systems to the grid.
DC isolators, including those in inverters, are required to meet the Australian standard AS 60947.3:2018 Low voltage switchgear and controlgear, Part 3: Switches, disconnectors, switch-disconnectors and fuse combination units (IEC 60947-3:2015 (ED. 3.2) MOD). This is the product standard for the switch used to isolate the inverter from the rest of the solar PV system. DC isolators are required to be certified.
Standards Australia updated the AS/NZS 4777.2 on 18 December 2020 (AS/NZS 4777.2:2020). The updated standard has a 12 month transition period that ends on 18 December 2021.
The update of the AS/NZS 4777.2 standard has included confirming the requirements for inverters with integrated DC isolators for isolation of PV array energy sources to conform with the requirements of AS 60947.3 Low voltage switchgear and controlgear, Part 3: Switches, disconnectors, switch-disconnectors and fuse combination units (IEC 60947-3:2015 (ED. 3.2) MOD). These requirements in AS/NZS 4777.2:2020 are not new and were taken from requirements of solar PV installation standard AS/NZS 5033:2014 +A1 +A2 Installation and safety requirements for photovoltaic (PC) arrays. The newly published AS/NZS 5033:2021 standard retains requirements for isolation of inverters.
Electrical safety legislation does not require independent certification of solar PV inverters to AS/NZS 4777.2:2020 as they are level 1 equipment within the Electrical Equipment Safety System (EESS). Responsible suppliers are required to be registered and to have evidence of compliance to the relevant standard. That evidence may be manufacturers’ test reports or responsible suppliers own test results, so long as the results are performed by competent persons in accordance with the EESS Equipment Safety Rules. The responsible supplier can make a declaration of compliance or may choose to use independent accredited testing and certification.
The requirement for DC isolators to be certified is not a new requirement either, with DC isolators being elevated to level 3 equipment in the EESS in 2018 with a 12 month transition. These requirements applied to DC isolators in individual enclosures and to DC isolators within inverters.
This information and application of requirements for certification of DC isolators were clarified in information provided in late 2019, however review of certifications has resulted in further clarification over the last 6 months by EESS electrical safety regulators. Due to the need for clarification, EESS electrical safety regulators have put in place further guidance material and processes to enable DC isolator testing to be appropriately applied.
The ESO is aware that these clarifications have resulted in some manufacturers and suppliers having difficulty in getting the accredited evidence to have their DC isolators certified to the Australian standard (AS 60947.3).