AS/NZS 5139

Written and checked by the Energy Merchants desk · Reviewed 3 October 2026

AS/NZS 5139 is the joint Australian and New Zealand standard for the safety of battery systems installed with power conversion equipment. The full title is Electrical installations: Safety of battery systems for use with power conversion equipment, and the current edition dates from 2019.

It covers where a battery can go, how it must be protected and how the installation is labelled. It is an installation standard, so it governs what the installer does on site rather than which product the customer buys.

What it covers on the job

• Where the battery can be mounted: restrictions apply near habitable rooms, exits, and in some cases ceiling or wall spaces.
• Separation from ignition sources and from other services.
• Protection devices, isolation and cable sizing.
• Ventilation, enclosure and signage.

Some rules depend on the battery’s technology and the installation class, so the answer for a garage differs from the answer for a wall inside a home. State regulators and distributors also add their own conditions on top.

In practice

For the Cheaper Home Batteries Program, installers must be accredited and must comply with the relevant standards, and evidence is reviewed. Location photos matter: a wide shot showing the battery in context, and close-ups of labelling, can answer a compliance question before it is asked. See the battery submission guide for the photo list.

Common confusion

AS/NZS 5139 is often mixed up with AS/NZS 4777.2. The first is about safe battery installation. The second is about how the inverter behaves when connected to the grid. A job can comply with one and fail the other.

It is also not a product approval. A battery can be on the CEC approved battery list and still be installed in a non-compliant spot.

Process and eligibility are in battery STCs, with more vocabulary in the certificate trading glossary and the glossary.