Battery Energy Storage Systems

Requirements

This guidance relates to installation and safety requirements that must be carried out by Registered Electrical Contractors (RECs) and Licensed Electrical Workers (LEWs) to ensure a safe and compliant battery system installation. LEWs and RECs have various legal obligations to install, be responsible for installation and inspect electrical work and equipment safely under the Electricity Safety Act 1998 (the Act) and the Electricity Safety (General) Regulations 2019.

This guidance is also relevant to Licensed Electrical Inspectors (LEIs) to ensure the completed installation is tested and verified in accordance with the Act and regulations.

As part of the legislative framework, the following Australian Standards are applicable to a Battery Energy Storage System (BESS):

• AS/NZS 5139: 2019 Electrical installations – Safety of battery systems for use with power conversion equipment
• AS/NZS 4777.1: 2024 Grid connection of energy systems via inverters, Part 1: Installation requirements
• AS/NZS 4509.1:2009 Stand-alone power systems, Part 1: Safety and installation
• AS/NZS 3000: 2018 Electrical installations (the Wiring Rules).

The full text of the Australian Standards can be purchased from the Standards Australia store.

Technical guidance

This page has been developed to provide clarity on clauses from the Standards that relate to the safe and compliant installation and inspection of a BESS.

When a BESS is installed, existing installations must be assessed to check that safety has not been affected.

Licensed electricians and inspectors are encouraged to review the guidance below before contacting us. If you have a question that is not addressed below, please contact the Renewable Energy Safety team.

Further questions and answers will be added on additional battery related topics as needed.

Residual current device (RCD) requirements for alternative supplies

Hazards may be created when a battery system is installed to an existing switchboard and provides an alternative supply (backup power) during a grid supply outage, as adequate protection against fault currents is not provided. This includes an earth leakage fault occurring in the connected final subcircuits.

Hazards may also be created if pre-existing RCDs are altered. When circuits are altered to be supplied from an alternative supply, the pre-existing RCDs may not be the correct type. They may be unsuitable for the new source of supply. In these cases, they may not operate correctly when an earth leakage fault occurs.

Type AC RCDs

From 1 May 2023:

• Type AC RCDs must not be installed in Australia. This includes like for like replacement. As noted by the Electrical Regulatory Authorities Council (ERAC) this change is due to the increased use of electronics, solar energy generation and other similar products with a high direct current (d.c) waveform component.
• Only Type A, Type B and Type F, RCDs should be used. Type A is the most suitable replacement of the previous Type AC RCD.

We recommend that electrical contractors advise customers of the new requirements. However, it is not mandatory to replace existing Type AC RCDs that have been installed in a permanent location, tested and certified prior to 1 May 2023.

Where a BESS has been installed and supplies power to existing Type AC RCDs, those RCDs may only remain if they have been verified to operate correctly and is of an RCD type specified by the inverter manufacturer.

Important: In no circumstances should Type AC RCDs be installed or be used to replace faulty or failed RCDs or residual current circuit breakers with overcurrent protection (RCBOs).

Questions and answers

Further reading

Disclaimer

The above guidance provides practical and technical guidance. It does not constitute legal advice. Licensed Electrical Workers, Registered Electrical Contractors and Licensed Electrical Inspectors should seek independent advice about their obligations under the Electricity Safety Act 1998 and the Electricity Safety (General) Regulations 2019.