VEU Rebate for Victoria: What the Program Actually Covers in 2026
Many Victorian homeowners search for a VEU rebate on solar batteries.
Then they find out the truth. The Victorian Energy Upgrades program does not fund home batteries directly. It covers many other energy-efficient upgrades instead.
So where does battery support actually come from? This guide explains what the VEU rebate covers, how the scheme works in 2026, and where battery buyers should look next.
| Quick Answer The VEU rebate is a Victorian Government discount for energy-efficient upgrades like heat pump hot water and insulation. It does not cover home battery storage. Victorian battery buyers instead use the federal Cheaper Home Batteries Program, while businesses claim battery value through VEU project-based activities. |
What Is the VEU Rebate?
The VEU rebate comes from the Victorian Energy Upgrades program, regulated by the Essential Services Commission. It was once called the Victorian Energy Efficiency Target scheme.
Actually, the program started back in 2009. Since then, it has helped more than 2.4 million Victorian homes.
In 2025, the state passed a bill extending the program through to 2045. So installers and homeowners now have long-term certainty.
Here is how the funding works. Then energy retailers must buy and hand in credits each year.
Each credit is called a VEEC, short for a Victorian energy efficiency certificate. One VEEC equals one tonne of greenhouse gas saved.
So providers earn these credits by installing approved products. Then they turn that value into your upfront discount.
2026 and 2027 Targets
The government locked in new targets for the scheme. So the VEU rebate program now aims for 4.4 million certificates in 2026, rising to 4.6 million in 2027.
Also, regulators expect around 6 million certificates to actually be created each year. That builds a healthy surplus and keeps the market stable.
Once, retailers who fell short only faced a modest penalty. Now the shortfall rate has risen to $100 per certificate, which pushes retailers to keep buying.
How the Program Works Step by Step
The process stays simple on your end. First, you contact an accredited provider.
Next, they check your home and current system. Then your quote shows the discount already applied. You never claim anything after the fact.
From Credit to Discount
Your VEU rebate size depends on two things. One is the credit price, and the other is how much greenhouse gas your upgrade saves.
Also, prices move with the market. So the same upgrade can offer a different discount from month to month.
Credit Fees and Deadlines
Providers pay a fee for each credit they create. That fee rose from $2.33 to $4.35 from 1 January 2026, as part of a wider cost-recovery update.
Then there is also a strict deadline. So credits must be created within six months after the year ends.
So a 2025 upgrade needs its credit locked in by 30 June 2026. This same deadline covers late claims too.
Act early if you already installed an approved product but never claimed the discount.
Does the VEU Rebate Cover Home Batteries?
Not directly. Instead, the VEU program has no set activity for home battery installs, even in 2026.
That surprises many people. After all, batteries are one of the most searched clean-energy products in Victoria right now.
Victoria did run an interest-free loan scheme for home batteries through Solar Victoria, but that’s closed now. It hit its 4,500-loan target and stopped taking new applications in 2025.
Solar Victoria still offers rebates for solar panels and hot water systems, and the income cap for those drops from $210,000 to $150,000 from 1 July 2026. That cap doesn’t apply to battery support, though, since the battery loan itself no longer exists.
The Federal Cheaper Home Batteries Program
Instead, the federal Cheaper Home Batteries Program adds its own discount on top. That support runs through the Small-scale Renewable Energy Scheme, administered by the Clean Energy Regulator.
It funds around 30 percent off the upfront cost of eligible battery systems between 5kWh and 100kWh. No separate government application is needed. Your installer applies the discount directly.
This program has grown fast. In its first six months, more than 155,000 households and small businesses claimed the discount, with most installs happening outside inner-city areas.
So in December 2025, the government expanded its budget from $2.3 billion to $7.2 billion over four years. That’s expected to help over 2 million Australians install a battery by 2030.
Then, from 1 May 2026, the calculation method changed. The Small-scale Technology Certificate factor now tapers by battery size and steps down every six months through 2030.
Still, the government says the aim is to hold the discount at roughly 30 percent for most typical systems, while discouraging oversized batteries bought purely to chase a bigger rebate.
So if a provider advertises a “VEU battery rebate” for your home, ask one simple question: which scheme actually pays for it?
Often, it turns out to be a federal or state incentive, just marketed loosely under the VEU name.
What the Program Covers for Households
The scheme funds many approved products. Here are the most common home upgrades covered by the VEU rebate in 2026:
- Heat pump hot water systems, swapped in for old electric or gas units, generally earning 10 to 30 certificates per home
- Reverse-cycle air conditioning, replacing older heating and cooling
- Ceiling insulation, a brand-new 2026 activity — live now for public and community housing, opening to all Victorian homes from 1 October 2026
- Induction cooktops, recently extended to cover more eligible households
- Efficient shower roses and other water-saving fixtures
Renters can access most upgrades too. But some, like heating and cooling, need landlord sign-off first.
Always check your own eligibility with a provider before you commit to any single product, since exact certificate numbers vary by climate zone and the system being replaced.
Business Battery Storage and the VEU Rebate
Business battery projects access VEU rebate value differently. Instead, companies tap credit value through project-based activities.
So these use real measurement data, not a fixed formula. Since June 2025, the program added new measurement methods for larger sites.
So these better capture the value that business batteries deliver. As a result, they produce a stronger credit outcome than the older method did.
That single change makes battery projects easier to finance. So this especially helps sites doing heavy peak shaving.
The scheme also added a Commercial and Industrial Solar activity, which commenced on 29 September 2025. It covers systems between 30kW and 200kW, with the program guide and application forms released by late November 2025.
Pairing that solar activity with a battery lets a site make, store, and use its own power. So this cuts grid costs further over time.
The scheme has also revised its high efficiency motor activity and updated eligibility rules for several existing activities, so it’s worth checking current terms even for a project you assessed a year ago.
For help sizing these systems correctly, see our guide on C&I vs Utility-Scale BESS.
How to Claim Your VEU Rebate
Follow these steps to claim your VEU rebate with any accredited provider:
- Confirm your home and current system qualify for an approved activity
- Pick an approved product from the VEU register
- Get a quote with the discount already taken off
- Have a licensed provider complete the install
- Let the provider handle the credit paperwork
You never touch the credit process yourself. Instead, your provider manages that step from start to finish.
What’s Changing Next: The VEU Strategic Review
The program isn’t standing still. Regulators are running a wider strategic review of the whole VEU framework in 2026.
So the aim is to modernise the VEU rebate scheme and better support electrification as more households switch to efficient, electric appliances.
A bill to amend the underlying Act is planned for state Parliament later in 2026. Formal stakeholder engagement, including public webinars, ran through March and April 2026.
Instead of assuming today’s rules are fixed for years, treat this guide as a snapshot. Always confirm current activity terms with an accredited provider before signing a quote.
Comparing VEU Rebate and Other Battery Incentives
The table below compares the main schemes Victorian homes and businesses actually use.
| Scheme | What It Covers | Who It Suits |
|---|---|---|
| VEU rebate (standard activities) | Hot water, heating, cooling, insulation | Homes and small businesses |
| Solar Victoria rebates | Solar panel and hot water rebates (battery loan closed in 2025); income-capped from July 2026 | Income-eligible homeowners |
| Federal Cheaper Home Batteries Program | Around 30% off usable battery capacity | Any eligible home nationally |
| VEU project-based activities | Credit value for custom battery and solar projects | Commercial and industrial sites |
Mixing up these schemes is common. Often, providers blend the language together in their marketing.
So knowing which body actually funds your discount helps you compare quotes fairly. It also guards you against a provider who overstates what the VEU rebate alone will cover.
Why the Mix-Up Happens So Often
Most Victorian energy schemes overlap in timing and paperwork. So it is easy to see why homeowners blur them together.
Often, one accredited VEU provider is also a Solar Victoria partner. That same firm might also process federal battery credits.
So one invoice can quietly bundle three discounts into a single number. Always ask for a clear, itemised breakdown before you sign anything.
Frequently Asked Questions
Is there a VEU rebate for solar batteries at home?
No — home battery storage is not a standard VEU activity. Solar Victoria’s battery loan has closed, so look at the federal Cheaper Home Batteries Program instead.
How much is the rebate worth?
That depends on the credit price and your specific upgrade. Prices shift with the market, so your provider confirms the exact figure before work starts.
Has the federal battery discount changed in 2026?
Yes. The calculation method changed from 1 May 2026, tapering by battery size. But the government still targets around a 30 percent discount for most typical systems.
Who is eligible in Victoria?
Most Victorian homes and small businesses qualify for at least one activity. There is no income test for most VEU upgrades, though renters may still need landlord approval.
Can businesses combine incentives?
Yes. So business batteries can often stack project-based credit value with federal Small-scale Technology Certificates. This pairs well with solar and often shortens the payback period too.
Further Reading
AS/NZS 3008.1.1:2025: What Changed for Cable Selection
AS/NZS 3008.1.1:2025 changed how engineers size cables across Australia and New Zealand. It’s also the fourth edition of the standard. It replaces the 2017 edition, which ran for eight years. So a cable calculation done today needs the new tables, not the old ones. This guide covers the real changes in AS/NZS 3008.1.1:2025. It also covers the new DC provisions and the transition timeline for each country. It’s one of three standards in Australia’s new battery rules.
| Quick Answer Quick answer: Standards Australia published AS/NZS 3008.1.1:2025 on 19 December 2025. It adds dedicated DC cable rating tables for the first time, covering circuits up to 1500V. Grouping and soil derating factors also got tighter. The standard renames “derating factor” to “correction factor.” Aluminium conductor ratings now extend down to 16mm². Both editions currently remain valid. Western Australia set 19 June 2026 as its full-compliance date. New Zealand expects to withdraw the 2017 edition around November 2026. |
What Is AS/NZS 3008.1.1?
AS/NZS 3008.1.1 sets the current-carrying capacity, voltage drop, and mechanical protection rules for cables in permanent electrical installations up to 0.6/1 kV. It also works alongside AS/NZS 3000, the wiring rules. Every cable has to clear three separate checks under this framework. AS/NZS 3008.1.1:2025 sets the numbers for all three checks.
The Three Checks Every Cable Must Pass
The first check is current-carrying capacity. A cable has to carry its design current continuously, without exceeding its insulation temperature rating. First, that figure comes from the base rating tables. Then the design derates it for ambient temperature, grouping, and depth of burial. Next, the second check is voltage drop. The drop from the supply point to the furthest load can’t exceed 5 percent of nominal supply voltage under AS/NZS 3000. For 230V single-phase, that’s 11.5V. For 400V three-phase, that’s 20V. Finally, the third check is earth fault loop impedance. So the total fault loop has to stay low enough that the upstream protective device disconnects within the AS/NZS 3000 Table 5.1 time limit.
| Check | Requirement |
| Current-carrying capacity (Iz) | Cable must carry the design current continuously without exceeding its insulation temperature rating, after derating for ambient temperature, grouping, and depth of burial |
| Voltage drop (Vd) | Must not exceed 5% of nominal supply voltage under AS/NZS 3000 (11.5V for 230V single-phase; 20V for 400V three-phase) |
| Earth fault loop impedance (Zs) | Total fault loop impedance must let the protective device disconnect within the AS/NZS 3000 Table 5.1 time limit |
Everything AS/NZS 3008.1.1:2025 Changed, at a Glance
| Change | Detail |
| New DC tables | Tables 3.21 and 3.22 cover DC circuits up to 1500V directly — first time in the standard’s history |
| AC tables rebuilt | Updated IEC 60287 thermal models; some ratings up 1-3% where 2017 was overly conservative |
| Aluminium range expanded | Ratings now start at 16mm², down from 25mm² |
| Grouping factors tightened | 6-circuit unperforated tray factor: 0.73 → 0.68 |
| Soil resistivity table | New “very dry soil” row added for desert/remote mining conditions |
| Terminology | “Derating factor” renamed to “Correction Factor (CF)” throughout |
New DC Cable Tables Up to 1500V
The single biggest change in AS/NZS 3008.1.1:2025 is new DC cable tables. Tables 3.21 and 3.22 now cover DC circuits directly. So that’s a first in the standard’s history. Before this edition, engineers sizing DC cables for solar strings, battery racks, or EV charging had no dedicated national table to work from. So they either approximated DC values from the AC tables using a 1.155 conversion factor, or leaned on manufacturer data instead. Now that workaround is gone. The new tables cover DC circuits up to 1500V directly. This matches where utility-scale solar and BESS DC bus voltages have been heading for years.
DC voltage drop also gets a cleaner formula under AS/NZS 3008.1.1:2025. DC has no reactive component. So the calculation is simpler than the AC version: voltage drop equals two times current times resistance times length, divided by 1000. So the factor of two accounts for both the outgoing and the return conductor. For a bipolar system with positive, neutral, and negative rails, the designer calculates each pole separately.
AC Table Changes
AC tables changed too, not just DC. AS/NZS 3008.1.1:2025 rebuilt the 2017 current rating tables using updated IEC 60287 thermal models. Some ratings actually increased, typically by 1 to 3 percent. That happened where the old 2017 figures turned out to be overly conservative. Also, table groupings got reorganised in places. This mainly cuts the risk of picking the wrong column. Aluminium conductor coverage expanded too. So ratings now start at 16mm², down from 25mm² in the old tables. This reflects how aluminium now shows up more in smaller, cost-sensitive solar DC circuits. These new ratings sit alongside the DC provisions covered in our Understanding BESS Specifications guide.
Revised Grouping and Soil Derating Factors
Not every change loosened requirements. Grouping and soil derating factors got tighter under AS/NZS 3008.1.1:2025, not looser. Cables on unperforated trays now carry lower correction factors than before. Take a six-circuit run on a solid tray, for example. It drops from a factor of 0.73 to 0.68. So that single change can push a cable size up a full commercial step on a real job. Field studies and thermal modelling done since 2017 found the old grouping factors weren’t conservative enough. Certain enclosed, tightly packed tray configurations were the main problem.
Soil thermal resistivity got a new addition, not just a tightened number. A “very dry soil” row now appears in the table. It also covers desert and remote mining conditions the 2017 edition never addressed. So that row matters for any underground DC run through genuinely arid ground. The old table simply had no category for it.
Terminology Change: Correction Factor Replaces Derating Factor
The term “derating factor” is gone from AS/NZS 3008.1.1:2025 entirely. It’s now called “correction factor,” abbreviated CF throughout the standard. Still, this is only a naming change, not a calculation change. Still, it matters for documentation. So design calculations and compliance paperwork using the old “derating factor” term should get updated to match.
AS/NZS 3008.1.1:2025 Transition Timeline
Timing differs by country and by state. Both the 2017 and 2025 editions currently remain valid for use. Western Australia’s Building and Energy division set 19 June 2026 as the date full compliance becomes mandatory there. That follows the same six-month transition period that applies to the AS/NZS 5139 battery safety amendment, published the same day. Meanwhile, New Zealand runs on its own clock. The Electrical Workers Registration Board expects the 2017 edition to get withdrawn around November 2026, once the standard 24-month transition period closes.
Mixing editions on one job causes real problems. Some 2017 cable sizes calculate slightly differently under the 2025 tables, even for straightforward AC circuits. So the safest approach for new design work is picking one edition. Size the entire job to AS/NZS 3008.1.1:2025, rather than checking some circuits against 2017 figures and others against 2025 figures.
Compliance Checklist for the 2025 Cable Standard
- Size all new DC circuits (solar strings, BESS DC bus, EV charging) using Tables 3.21 and 3.22, not the old AC-conversion workaround.
- Recalculate any six-or-more-circuit run on an unperforated tray against the tightened correction factors.
- Check underground DC runs in arid conditions against the new “very dry soil” resistivity row.
- Update design documentation and compliance paperwork to use “Correction Factor (CF)” instead of “derating factor.”
- Confirm your state’s specific compliance timeline before assuming both editions remain acceptable indefinitely.
- Size an entire job to one edition of the standard — don’t mix 2017 and 2025 figures on the same project.
Frequently Asked Questions
When was AS/NZS 3008.1.1:2025 published?
It was published on 19 December 2025, the same day as AS/NZS 5139 Amendment 1. Some secondary sources describe it as a late-2024 publication, but the standard’s own front matter and Western Australia’s government notice both confirm the December 2025 date.
Does AS/NZS 3008.1.1:2025 cover DC cable sizing?
Yes, for the first time. Tables 3.21 and 3.22 provide dedicated DC current rating tables for circuits up to 1500V, replacing the previous workaround of approximating DC values from AC tables.
What happened to the term “derating factor”?
AS/NZS 3008.1.1:2025 renamed it to “Correction Factor,” abbreviated CF. It’s the same calculation, just updated terminology that should be reflected in new design documentation.
Do I have to use the 2025 edition right now?
Not everywhere yet. Both editions remain valid during the transition. Western Australia requires full compliance from 19 June 2026. New Zealand expects to withdraw the 2017 edition around November 2026. Check your specific state’s position before assuming a date.
Can I mix 2017 and 2025 cable sizing on the same project?
It’s not recommended. Some cable sizes calculate slightly differently between editions, even for standard AC circuits. Size the entire job to one edition to avoid inconsistent results.
Further Reading
- Australia’s New Battery Rules: The 2026 Compliance Stack
- AS/NZS 5139 Amendment 1: What Changed for Battery System Safety
- AS/NZS 4777.2 Amendment 2: What Changed for Inverter Requirements
- Updated Electrical Installation Standards — WA Government
- AS/NZS 3008.1.1:2025 Updates for Solar Cable Design — GSES
- Understanding BESS Specifications
AS/NZS 4777.2 Amendment 2: What Changed for Inverter Requirements
AS/NZS 4777.2 Amendment 2 changed how Australia approves grid-connect inverters. Standards Australia published it on 23 August 2024. It became mandatory exactly one year later. Also, it now applies to every new grid-connect install. So any inverter installed today needs to meet it. So this guide covers every real change. It also covers the region settings you need to check, and what happened to inverters already on the approved list. It’s one of three standards in Australia’s new battery rules.
| Quick Answer Quick answer: It became mandatory on 23 August 2025, after a 12-month transition. It makes six changes. New supply terms. Fewer tests for battery-only gear. New generation limit rules. Updated Region C set points. New paperwork rules. New clauses for two-way EV charging. Older CEC inverter listings didn’t carry over automatically. So manufacturers had to submit a declaration and evidence of the updated region settings before the deadline, or their models came off the approved list. |
What Is AS/NZS 4777.2 Amendment 2?
AS/NZS 4777.2 is the standard that governs how grid-connect inverters behave once installed. It’s also Part 2 of a two-part standard. Part 1 covers general requirements. Part 2 covers the inverter-specific rules that matter most for design work. AS/NZS 4777.2 Amendment 2 is the second update to the 2020 edition. So it’s formally known as AS/NZS 4777.2:2020 Amendment 2:2024.
The Six Changes in AS/NZS 4777.2 Amendment 2
Six changes make up the bulk of AS/NZS 4777.2 Amendment 2. First, AS/NZS 4777.2 Amendment 2 updates supply type terminology, for clearer alignment with AS/NZS 4777.1. Then second, battery-only products no longer need IEC 62109 testing. That cuts duplicate certification work. Third, generation limit control parameters changed. Fourth, AS/NZS 4777.2 Amendment 2 updates Region C set points. Fifth, documentation and marking rules changed. Sixth, and most talked-about, new clauses cover electric vehicle supply equipment.
| Change | What It Means |
| Supply type terminology | Updated for clearer alignment with AS/NZS 4777.1’s supply-type definitions |
| IEC 62109 removed | Battery-only products no longer need this testing, cutting duplicate certification work |
| Generation limit parameters | Control parameters for generation limiting were updated |
| Region C set points | Updated power quality set points specifically for Region C networks (Horizon Power, TasNetworks, remote Power & Water) |
| Documentation and marking | Updated requirements for product documentation and equipment marking |
| EVSE clauses (new) | New clauses covering electric vehicle supply equipment for bidirectional charging |
When AS/NZS 4777.2 Amendment 2 Took Effect
So Standards Australia set a 12-month transition window. During that time, manufacturers could apply under the old or the new standard. After 23 August 2025, the Clean Energy Council only accepts Amendment 2 products for new listings. The Clean Energy Council runs this through its approved inverter list. Most network operators use that list directly.
What Happened to Existing CEC Inverter Listings
Existing listings didn’t need full re-testing for AS/NZS 4777.2 Amendment 2. Still, manufacturers had to prove compliance. The Clean Energy Council asked for a signed declaration. It also asked for proof of the updated region settings for every model. That proof could be a product manual, an install guide, or a screenshot from a monitoring app. Anything missing by 23 August 2025 meant the model came off the approved list. The Clean Energy Council’s standards-change page has the full manufacturer declaration template and process.
So this matters for anyone still specifying against an old product sheet. An inverter that was genuinely CEC-approved two years ago may not carry that status today. So always check the live CEC list at the point of design, not a cached copy from a previous project.
CSIP-AUS and Smart Communication
The updated standard introduced CSIP-AUS, the Common Smart Inverter Profile for Australia. Still, this is a communication protocol, not a hardware requirement. It lets network operators manage dynamic export limits, and in some cases apply remote curtailment. A compliant inverter under AS/NZS 4777.2 Amendment 2 lets the grid talk back to it, not just receive power one-way.
Region-Based Power Quality Settings
Power quality settings still follow a region-based structure: Australia A, B, or C. Most of the country falls under Region A. Western Power alone makes up Region B. Tasmania and remote areas fall under Region C, covering Horizon Power, TasNetworks, and remote parts of Power & Water. The full list is in the table below. AS/NZS 4777.2 Amendment 2 changed the Region C set points specifically. So a Tasmanian or remote WA install needs extra care here. Energy Networks Australia’s FAQ has the full DNSP contact list for each state.
| Region | Distribution Network Service Providers (DNSPs) |
| Australia A | Ausgrid, AusNet Services, Endeavour Energy, Essential Energy, Ergon Energy, Energex, Evoenergy, Jemena, CitiPower, Powercor, United Energy, SA Power Networks, Power & Water (some areas) |
| Australia B | Western Power |
| Australia C | Horizon Power, TasNetworks, Power & Water (remote networks) |
Warranty Replacement Rules
Warranty replacements get a narrow exception. Owners can still swap in an older-standard inverter under warranty, but only if three conditions hold together. The replacement has to be the same make and model. It has to genuinely be a warranty case. And the inverter has to match the existing connection agreement. Also, DNSPs still need to approve the replacement first. Outside those conditions, a warranty swap needs a current AS/NZS 4777.2 Amendment 2 compliant unit.
Bidirectional EV Charging: Mode 3 vs Mode 4
Bidirectional EV charging is where this amendment gets genuinely new. It’s not just a terminology refresh. So it splits two charging modes apart. Mode 4 charging sends power to and from the vehicle through wall-mounted gear with its own inverter. That gear now falls under AS/NZS 4777.2 Amendment 2 directly. It also sits inside the CEC’s approved inverter list. Mode 3 also sends power both ways, but the inverter lives inside the car instead. The Clean Energy Council is still working out how much of that setup falls under the same listing rules.
AS/NZS 4777.2 Amendment 2 Compliance Checklist
- Confirm the specific inverter model against the live CEC approved list, not a cached spec sheet or marketing page.
- Confirm the correct region setting (A, B, or C) for the installation’s DNSP — Region C set points changed under this amendment.
- Check whether any EV charging equipment on the job is Mode 3 or Mode 4, since that determines which listing requirements apply.
- For battery-only power conversion equipment, confirm whether the IEC 62109 exemption applies to the specific product.
- If proposing a warranty replacement with an older-standard inverter, verify all three conditions: same make and model, genuine warranty case, and matching connection agreement.
- Get DNSP approval before installing any warranty replacement inverter.
Frequently Asked Questions
When did AS/NZS 4777.2 Amendment 2 become mandatory?
Standards Australia published it on 23 August 2024. After a 12-month transition, it became mandatory for new inverter installations from 23 August 2025.
Does an old CEC inverter listing still work after Amendment 2?
Not automatically. Manufacturers had to submit a declaration and evidence of updated region settings before 23 August 2025. Any model without that evidence was removed from the approved list on that date.
What is CSIP-AUS?
CSIP-AUS is the Common Smart Inverter Profile for Australia — a communication protocol introduced with this amendment that lets network operators manage dynamic export limits and, in some cases, apply remote curtailment.
What’s the difference between Mode 3 and Mode 4 EV charging under this amendment?
Mode 4 charging uses wall-mounted Electric Vehicle Supply Equipment with its own inverter, which falls directly under AS/NZS 4777.2 and the CEC’s approved inverter list. Mode 3 charging also flows power both ways, but the inverter sits inside the vehicle instead — how that gets covered by the listing framework is still being finalised.
Can I still install an inverter that only meets the pre-Amendment 2 standard?
Only as a like-for-like warranty replacement, and only if the replacement is the same make and model, is genuinely for warranty purposes, and is set up to match the existing connection agreement. The DNSP still has to approve it first.
Further Reading
AS/NZS 5139 Amendment 1: What Changed for Battery System Safety (2025–2026)
AS/NZS 5139 Amendment 1 changed how batteries get installed across Australia and New Zealand. It arrived on 19 December 2025. So if you designed a BESS install before that date, several of your default assumptions just moved. This guide walks through every real change. New definitions. New clearance figures. A genuinely useful garage exception. A new appendix for fault current calculations. It’s one of three standards in Australia’s new battery rules.
| Quick Answer Quick answer: AS/NZS 5139 Amendment 1 updates 18 clauses. It also adds five new figures, plus Appendix I for calculating cell short-circuit current. It’s mandatory now in NSW. Western Australia set a specific deadline of 19 June 2026, after a six-month transition. The headline practical change is a new exception. Batteries can now sit within 600mm of a garage opening wider than 900mm, provided safe egress is preserved. |
What Is AS/NZS 5139 Amendment 1?
AS/NZS 5139:2019 is the standard that governs safety for battery energy storage systems. It covers systems connected to power conversion equipment. It replaced the older AS 4086.2 standard back in 2019. AS/NZS 5139 Amendment 1 doesn’t replace this base standard. Instead, it updates specific clauses. It adds new figures. It also adds one new appendix. The rest of the 2019 standard stays in force. The full amended text is available through the Standards Australia Store.
The full clause list is in the table below. It also touches Figures 2.11 and 2.12, and adds five entirely new figures: 4.1A, 4.1B, 4.1C, 4.1D, and 4.2A. Appendix I is new. So is a set of new Bibliography references.
Everything AS/NZS 5139 Amendment 1 Changed, at a Glance
| Type | Reference |
| Clauses updated | 1.3, 3.2.3.3, 4.2.2.1, 4.2.2.2, 4.2.4.2, 4.2.5, 5.2.2.1, 5.2.2.2, 5.2.4.2, 5.3.1.2.1, 5.3.1.3.8, 6.3.6.4, 7.2, 7.7, 7.8, 7.9, 7.10, 7.11 |
| Figures updated | 2.11, 2.12 |
| Figures added (new) | 4.1A, 4.1B, 4.1C, 4.1D, 4.2A |
| Appendix added (new) | Appendix I — calculating cell short-circuit current |
| Bibliography | New references added |
When AS/NZS 5139 Amendment 1 Takes Effect
Timing isn’t the same in every state. NSW treats the amendment as mandatory right away. Any install that misses the updated requirements no longer complies with the Standard there. WA took a different path. It set a full-compliance date of 19 June 2026, six months after publication. Until then, either the old or the new version is fine. Other states are still working out their own position. So check with your state regulator before you quote a date to a client.
| Jurisdiction | Position | Source |
| NSW | Mandatory immediately on publication (19 Dec 2025) | NSW Building Commission advisory |
| Western Australia | Full compliance required from 19 Jun 2026, after a 6-month transition where either edition is acceptable | WA Building and Energy notice |
| Queensland | Amendment issued and communicated to electricians; specific compliance date not published in the source reviewed | WorkSafe QLD eSafe newsletter |
| Other states/NZ | Not confirmed in this research pass — verify with the relevant state or NZ regulator before quoting a date | — |
New Definitions Under AS/NZS 5139 Amendment 1
Clause 1.3 covers terms and definitions, and it picked up real changes. The main addition is a new definition: a battery energy storage system room. That’s a dedicated room. It holds the battery, the power conversion equipment, and other BESS accessories. A note attached to this definition matters just as much as the definition. It says a multi-purpose room doesn’t count as “dedicated,” just because a battery sits in it. A garage or a general storage room are both good examples.
Three other definitions picked up clarifying notes too, with practical examples. So electricians should still read Clause 1.3 in full. Drawings and compliance paperwork need to use the amended wording exactly.
New Clearance Figures: 4.1A Through 4.2A
The amendment replaces the old typical BESS installation diagrams with five new figures. First, Figure 4.1A covers egress clearance in a corridor, hallway, or lobby. Then Figure 4.1B covers clearance to doors and openings. Also, Figure 4.1C adds further detail to the clearance picture. Figure 4.1D shows a side-view diagram of clearance from restricted locations, with the familiar 600mm front clearance and 900mm above-battery clearance both drawn out. Finally, Figure 4.2A covers clearances for battery connection access, split by whether the connection is DC or AC.
One structural cleanup came along with the new figures. Also, the standard used to repeat similar diagrams in Section 5. So the amendment removes that duplication. Section 5 now just refers back to the Section 4 figures instead of reprinting them.
The Garage Door Exception — Clause 4.2.2.2
The most talked-about change is a new exception for garage installations. Under the amended Clause 4.2.2.2, a battery can now sit within 600mm of an opening wider than 900mm — a typical garage door, in other words — as long as the opening still allows sufficient clearance for safe egress, and the clearance is no less than 1m from any front or side a person might need to pass through during an exit.
This matters because garages are the preferred spot for a lot of installers. They’re usually not living spaces, they’re weather-protected, often shaded, and close to the switchboard. But the old blanket 600mm rule ruled out a lot of good garage walls, just because of a wide roller door. The amendment keeps the safety goal in place. People still need a safe way out. It just stops punishing a battery for sitting near a large opening when someone could still walk past it safely.
In practice, this means a designer needs two numbers, not one. The first is the 600mm distance to the opening itself. The second is the 1m clearance from whichever front or side edge a person would need to pass. So both conditions have to hold at the same time. A wide garage door with a wall corner narrowing the walk-through space to less than a metre still fails, even if the 600mm figure looks fine on a drawing.
Worked Example
A garage has a 2.4m-wide roller door. The nearest wall section suitable for a battery sits 500mm from the door opening. Under the amended clause, 500mm is within the 600mm allowance, and the door is well over the 900mm width threshold. So far, this passes. But the same wall has a support post 800mm from the door edge, narrowing the usable walk-through space to 800mm at that point. Since 800mm is under the 1m minimum clearance the amendment also requires, this specific layout still fails — even though the headline 600mm number looks fine. Moving the battery, or resolving the post clearance, is the fix.
Inverters as Associated Appliances
The amendment also reclassifies inverters. Power conversion equipment now counts as an associated appliance. So it can go inside a restricted location, where it couldn’t before. That’s a useful change for compact installs, where wall space near the battery is already tight.
Fire Barrier and Overcurrent Protection Changes
Fire barrier requirements moved the other way. Stricter, not looser. So exempt materials used as a barrier to a habitable room now need a minimum thickness of 6mm. Also, building materials within 1 metre of a battery system classed as a chemical hazard pick up new requirements.
Paralleled pre-assembled battery systems get a new rule for overcurrent protection. The protective device’s kA rating now has to cover the combined fault current of every paralleled unit, not just the biggest one. That’s a real change for multi-unit homes and light commercial jobs. Two or three battery modules often get paralleled to hit a target capacity.
To make that calculation possible, the amendment adds Appendix I. It sets out the method for calculating cell short-circuit current within a battery system. So that’s the number a designer needs before sizing the paralleled OCPD correctly. This connects directly to broader short-circuit protection design work on the DC side of a BESS installation. This connects directly to broader short-circuit protection design work on the DC side of a BESS installation.
Safety Data Sheet Requirements
Safety Data Sheet handling picked up a clarification too. A physical copy of the SDS must be provided on site. It also has to stay protected from damage or degradation. The standard specifically mentions storing it in a sealed, durable, clear pouch as an acceptable method. So treat SDS storage as part of the handover package, not an afterthought bolted on at final inspection.
Background: Restricted Locations Under AS/NZS 5139
It helps to know what this amendment did NOT change. The base restricted-location rules still apply. Batteries still can’t sit within 600mm of an exit, a window edge, a vent into a living room, or an appliance. They still can’t sit within 900mm below any of those. Ceiling spaces, wall cavities, roofs, stairways, walkways, escape routes, and living rooms themselves are still off-limits. The ERAC Battery Energy Storage System Guideline backs up these same rules. None of this changed. The amendment only added the wide-opening exception above, plus the inverter reclassification.
Restricted Locations — Unchanged by Amendment 1
- Within 600mm of any exit or entry
- Within 600mm of any window’s vertical side, or a ventilation opening into a habitable room
- In an evacuation or designated escape route
- Within 600mm of any appliance
- Within 900mm below any of the items above
- In ceiling spaces or wall cavities
- On roofs
- Under stairways or access walkways
- Within a habitable room itself
AS/NZS 5139 Amendment 1 Compliance Checklist
- Confirm the installation drawings use Clause 1.3’s updated terminology, including the new battery energy storage system room definition.
- Check clearance layouts against the new Figures 4.1A–4.2A, not the pre-amendment diagrams.
- If relying on the garage-door exception, verify both the 600mm opening distance AND the 1m walk-through clearance — not just one of them.
- Confirm inverter placement against the updated associated-appliance classification if it sits in a restricted location.
- Check fire-barrier materials meet the 6mm minimum thickness where used as exempt materials.
- For paralleled pre-assembled battery systems, recalculate the OCPD kA rating against the combined fault current using Appendix I.
- Confirm a physical SDS copy is on site and stored in a protective pouch before handover.
- Verify your state’s specific compliance timeline before telling a client the installation is (or isn’t) required to meet Amendment 1 yet.
Frequently Asked Questions
When did AS/NZS 5139 Amendment 1 take effect?
It was published on 19 December 2025. NSW treats it as mandatory immediately. Western Australia requires full compliance from 19 June 2026, after a six-month transition period. Confirm the position in your own state before quoting a date.
What is the garage door exception under this amendment?
Under the amended Clause 4.2.2.2, a battery can be installed within 600mm of an opening wider than 900mm — such as a garage door — provided safe egress is maintained and clearance is no less than 1m from any front or side a person might need to pass through.
Does this amendment change where inverters can be installed?
Yes. Power conversion equipment is now classified as an associated appliance, which means it can be installed inside a restricted location where it previously couldn’t.
What is Appendix I, and what does it calculate?
Appendix I is a new addition that sets out how to calculate cell short-circuit current within a battery system. It’s needed to correctly size overcurrent protection for paralleled pre-assembled battery systems under the amendment’s new kA rating requirement.
Do the pre-existing restricted-location rules still apply under Amendment 1?
Yes, unchanged. Batteries still can’t be installed within 600mm of exits, windows, ventilation openings, or appliances, within 900mm below those items, or in ceiling spaces, wall cavities, roofs, under stairways, escape routes, or habitable rooms. Amendment 1 only added the specific wide-opening exception and the inverter reclassification — it didn’t touch the base restricted-location list.
Further Reading
Australia’s New Battery Rules: The 2026 Compliance Stack
Australia has new battery rules for 2026, and they arrived from three different directions at once. Between August 2025 and December 2025, regulators updated the inverter standard, the battery safety standard, and the cable selection standard. Two of them landed on the very same day. So anyone installing, supplying, or specifying a BESS in Australia now answers to all three of these new battery rules. Miss one, and the other two won’t save the project.
| Quick Answer Australia’s new battery rules for 2026 span three standards. AS/NZS 5139:2019 Amendment 1 (published 19 Dec 2025) covers battery system safety. AS/NZS 4777.2:2020 Amendment 2 (mandatory from 23 Aug 2025) governs inverter performance and grid behaviour. AS/NZS 3008.1.1:2025 (also published 19 Dec 2025) sets cable selection and DC ratings. In Western Australia, full compliance with both the 5139 and 3008.1.1 updates is required from 19 June 2026, following a six-month transition period — other states administer their own timelines. A compliant BESS install needs all three standards, and a battery’s international product certifications (IEC 62619, UL 1973, UN38.3) do not substitute for any of them. |
What Are Australia’s New Battery Rules?
Together, Australia’s new battery rules form what’s best understood as a compliance stack, not three unrelated updates. A battery energy storage system never sits under a single rulebook. Instead, it sits at the intersection of three. AS/NZS 5139 governs how the battery gets installed, ventilated, and protected. AS/NZS 4777.2 governs how the inverter behaves once it talks to the grid. AS/NZS 3008.1.1 governs every cable that connects the two. So a design can pass one standard and still fail the job. Also, it only takes one missed layer to cause it.
It’s also worth separating two things international suppliers often conflate. So battery product certification and Australian installation compliance are not the same thing. A cell or module can carry IEC 62619, UL 1973, and UN38.3 certification and still fail an Australian project if the installation, inverter, or cable design doesn’t separately satisfy the three standards below.
This page works as a living hub, not a one-time post, since Australia’s new battery rules will keep changing. Also, each standard below links out to its own detailed guide as those go live. As amendments publish, this hub updates first, then the change log at the bottom records exactly what moved and when. Bookmark this page, not a single standard’s guide — the compliance stack shifts as a set, not one piece at a time.
Australia’s New Battery Rules: Compliance Stack Overview
The table below summarises where each standard sits today. Full detail on each one follows in its own section, and a dedicated guide for each standard is in progress.
| Standard | Governs | Published | Mandatory From | Administered By |
| AS/NZS 5139:2019 | Battery system and BESS installation safety | Amendment 1: 19 Dec 2025 | Immediate in NSW; full compliance from 19 Jun 2026 in WA (6-month transition) — confirm with your state regulator | Standards Australia / Standards NZ; state electrical safety regulators |
| AS/NZS 4777.2:2020 | Grid-connect inverter performance | Amendment 2: Aug 2024 | 23 Aug 2025 | Standards Australia / Standards NZ; Clean Energy Council; DNSPs |
| AS/NZS 3008.1.1 | Cable selection, current-carrying capacity, DC ratings to 1500V | 2025 edition: 19 Dec 2025 | Full compliance from 19 Jun 2026 in WA (6-month transition); NZ 2017 edition withdrawal ~Nov 2026 | Standards Australia / Standards NZ |
Note on dates: AS/NZS 5139 Amendment 1 and AS/NZS 3008.1.1:2025 were both published on 19 December 2025, not on separate dates. Mandatory compliance timing varies by state; Western Australia’s Building and Energy division has published the clearest specific deadline (19 June 2026, after a six-month dual-acceptance period), while NSW guidance describes the 5139 update as mandatory immediately on publication. Confirm the position in your specific state before quoting a date to a client.
Australia’s New Battery Rules, Part 1: AS/NZS 5139:2019 Amendment 1 — Battery System Safety
Amendment 1 to AS/NZS 5139:2019 was published on 19 December 2025. The NSW Building Commission confirms that a battery installation failing to meet the updated requirements no longer complies with the Standard in NSW.
Western Australia’s Building and Energy division has set a specific full-compliance date: 19 June 2026. That follows a six-month transition period, during which both the 2019 base standard and the amended version are acceptable.
So the amendment touches definitions, installation diagrams, clearances, overcurrent protection, and safety documentation.
What Changed in Amendment 1
Several changes matter for day-to-day design work. First, Clause 1.3 introduces new and updated definitions. So terminology used on drawings needs a fresh check. Also, the typical BESS installation diagrams were revised — new figures 4.1A through 4.2A cover egress clearance, door and opening clearance, and unimpeded access to a pre-assembled integrated BESS.
Location, Fire Barriers, and Overcurrent Protection
Still, location rules loosened in one specific way. A battery system may now sit within 600mm of an opening, provided that opening is wider than 900mm, such as a garage door. Inverters are also now treated as an associated appliance, and are permitted inside a restricted location, which they previously were not.
Fire-barrier requirements got stricter instead. So exempt materials used as a barrier to a habitable room must now be at least 6mm thick. Building materials within 1 metre of a battery system classed as a chemical hazard also face new requirements.
Also, overcurrent protection for paralleled pre-assembled battery systems changed. The protection device’s kA rating must now match or exceed the combined fault current of every paralleled battery system, not just one. So a new Appendix I sets out how to calculate that cell short-circuit current. This pairs directly with existing short-circuit protection design work on the DC side of the system.
Safety Data Sheets
Safety Data Sheet handling was clarified too. A physical copy must stay on site, protected from damage — for example inside a sealed, durable, clear pouch. Installers should treat SDS storage as part of the handover package, not an afterthought.
AS/NZS 5139 Compliance Checklist for BESS Suppliers and Installers
- Battery enclosure design meets updated location and clearance rules
- Installation clearances reflect revised figures 4.1A–4.2A
- Fire protection strategy accounts for the 6mm minimum barrier thickness
- Overcurrent protection kA rating is calculated against combined paralleled fault current (Appendix I)
- Safety Data Sheets are on-site in a protective pouch
- Installation manuals and terminology match Clause 1.3 definitions
- Maintenance and emergency access procedures documented
Full guide: AS/NZS 5139 Battery Safety Standard — Amendment 1 Explained
Australia’s New Battery Rules, Part 2: AS/NZS 4777.2:2020 Amendment 2 — Inverter Requirements
AS/NZS 4777.2:2020 Amendment 2 governs how grid-connect inverters behave once installed. It is the second of the three new rules. Standards Australia released it in August 2024, then set a 12-month transition period. Full compliance became mandatory from 23 August 2025. So it now applies to every new low-voltage grid-connect inverter installation. That makes it the second pillar of the battery compliance stack.
CSIP-AUS and Smart Communication
First, the headline addition is CSIP-AUS, the Common Smart Inverter Profile for Australia. This communication protocol lets network operators manage dynamic export limits. In some cases, it also allows remote curtailment. A modern compliant inverter is built to be talked to by the grid, not just to push power onto it. The Clean Energy Council’s approved inverter list now reflects Amendment 2 as the current benchmark. Clean Energy Council’s approved inverter list now reflects Amendment 2 as the current benchmark.
What Installers Must Check
Older CEC listings did not carry over automatically. So manufacturers had to submit a declaration plus supporting evidence that their products met Amendment 2 before their listings kept standing. Installers should verify the exact model against the current CEC list — never trust a listing checked before August 2025.
Power quality settings still follow a region-based profile — Australia A, B, or C — set by the local distribution network service provider. This includes the ride-through behaviour covered in our LVRT and HVRT guide. This includes the ride-through behaviour covered in our LVRT and HVRT guide.
EV and V2G Provisions
Next, the amendment adds requirements supporting vehicle-to-grid and vehicle-to-building inverters. So bidirectional EV charging now shares the same grid-connect framework as solar and battery inverters. See our PCS overvoltage protection guide for how these settings interact with anti-islanding and ride-through coordination.
AS/NZS 4777.2 Compliance Checklist
- CEC approval status confirmed against the current list, not a pre-Aug-2025 listing
- Correct firmware version installed
- Grid protection settings match the DNSP’s region profile (A, B, or C)
- Anti-islanding function verified
- Export control compatibility confirmed
- CSIP-AUS capability documented
- LVRT/HVRT settings verified against ride-through requirements
Full guide: AS/NZS 4777.2 Amendment 2: What Changed for Inverter Requirements
Australia’s New Battery Rules, Part 3: AS/NZS 3008.1.1:2025 — Cable Selection
AS/NZS 3008.1.1:2025 is the third of Australia’s new battery rules. It replaces the 2017 edition that governed cable selection for eight years. Standards Australia published the new edition on 19 December 2025. That’s the same day as AS/NZS 5139 Amendment 1, not late 2024 as some secondary sources report. Both editions currently remain valid during the transition. In Western Australia, full compliance with the 2025 edition is required from 19 June 2026. This is the third and final pillar of the battery compliance stack.
New 1500V DC Cable Ratings
So the most significant scope change is new DC cable rating provisions up to 1500 volts. The 2017 edition barely covered DC circuits above 1000 volts. That left utility-scale solar strings and BESS rack-to-inverter cabling without a proper rating table. So the 2025 edition adds explicit current-rating tables for single-core DC cables, plus new provisions for DC fast-charger cabling. These new tables are already referenced alongside the DC specifications in our Understanding BESS Specifications guide.
Revised Grouping and Soil Derating Factors
Also, grouping and soil derating factors tightened. Cables on unperforated trays now carry lower derating factors than before. A six-circuit run on a solid tray, for instance, drops from a factor of 0.73 to 0.68. So that can push a cable size up a full commercial step. A new “very dry soil” row now covers desert and remote mining conditions the 2017 tables never addressed.
Transition Timeline
New Zealand runs its own transition clock. Still, the 2025 edition became available there at the same time as in Australia. But the 2017 edition is expected to be formally withdrawn around November 2026, once the standard 24-month transition period closes. Western Australia’s Building and Energy division confirms that both AS/NZS 5139 Amd 1:2025 and AS/NZS 3008.1.1:2025 were published 19 December 2025, with full compliance required from 19 June 2026 following a six-month period in which either edition is acceptable.
AS/NZS 3008.1.1 Compliance Checklist
- Cable voltage rating confirmed for the full DC operating window (up to 1500V where applicable)
- Maximum operating current calculated against the 2025 tables
- Short-circuit withstand capability checked against combined fault current
- Grouping and derating factors recalculated for unperforated trays with six or more circuits
- Soil thermal resistivity checked for underground runs, including the new “very dry soil” category
- Voltage drop calculation completed for the full cable run
Full guide: AS/NZS 3008.1.1:2025: What Changed for Cable Selection
Battery Product Certification vs. Australian Installation Compliance
One misunderstanding shows up often among international BESS suppliers. Often, they assume battery product certification alone satisfies Australia’s new battery rules and allows market entry. It doesn’t. A battery module can pass every relevant international safety test and still fail an Australian project. That happens whenever the installation, inverter, or cable design doesn’t separately satisfy AS/NZS 5139, AS/NZS 4777.2, and AS/NZS 3008.1.1. So product certification and installation compliance are different regulatory layers, and both are required.
Common Battery Product Certifications Referenced in Australian BESS Projects
| Certification | What It Covers | Typical Use |
| IEC 62619 | Industrial lithium-ion battery safety: electrical abuse protection, thermal safety, operational reliability | Commercial and industrial BESS, telecom energy storage |
| UL 1973 | Stationary battery safety at module, rack, and system level | Utility-scale and North American-influenced BESS specifications |
| UN38.3 | Transport safety: altitude, temperature, vibration, shock, short-circuit, and overcharge testing | Required before any international lithium battery shipment |
| IEC 63056 | Secondary lithium battery safety for stationary energy storage applications | Residential and commercial ESS, increasingly requested alongside IEC 62619 |
For a full breakdown of these certifications — what each one tests, who issues it, and typical cost and timeline — see our complete BESS Certifications Guide.
So none of these substitute for AS/NZS 5139 installation compliance, AS/NZS 4777.2 inverter or CEC approval, or AS/NZS 3008.1.1 cable design. For suppliers planning an Australian entry, compliance needs to be considered during BESS design. Enclosure layout, protection settings, and documentation format all belong at the design stage. None of it works well retrofitted after manufacturing is locked in.
How Australia’s New Battery Rules Work Together on One Job
These three standards do not operate in isolation on a real job. Take a paralleled battery system as an example, since it shows how Australia’s new battery rules stack on top of one another. First, AS/NZS 5139 Amendment 1 sets the required kA rating for its overcurrent protection device, based on the combined fault current. Then that same fault current drives the short-circuit withstand check on the DC cable under AS/NZS 3008.1.1. Meanwhile, the inverter tying it all to the grid still needs a valid CEC listing under AS/NZS 4777.2 Amendment 2. Miss any one layer, and the other two will not save the design.
So treat the battery compliance stack as one system, not three separate checklists. A designer who only checks the inverter datasheet will eventually hit a cable run that neither standard alone was built to catch. The same goes for a designer who only checks enclosure clearances. Check all three, every time — and check that the underlying battery product certification is in place before any of it matters.
Change Log — Australia’s New Battery Rules Hub
| Date | Version | Update |
|---|---|---|
| 26 Jul 2026 | v1.0 | Initial publication covering AS/NZS 5139 Amendment 1, AS/NZS 4777.2 Amendment 2, and AS/NZS 3008.1.1:2025. |
| 26 Jul 2026 | v2.0 | Corrected the AS/NZS 3008.1.1:2025 publication date to 19 December 2025. Added Western Australia’s specific 19 June 2026 compliance date. Added a new section comparing battery product certification (IEC 62619, UL 1973, UN38.3) with Australian installation compliance. |
| 26 Jul 2026 | v3.0 | Updated the page framing to lead with “Australia’s new battery rules” for clarity. |
| 26 Jul 2026 | v3.1 | Finalised page details ahead of publishing. |
| 28 Jul 2026 | v3.2 | Published all three detailed guides — AS/NZS 5139 Amendment 1, AS/NZS 4777.2 Amendment 2, and AS/NZS 3008.1.1:2025 — and linked them from their respective sections above. |
Australia’s New Battery Rules Checklist for 2026
- Confirm every new BESS design references AS/NZS 5139:2019 including Amendment 1, and check your state’s specific enforcement timeline.
- Check the inverter model against the current CEC approved list for AS/NZS 4777.2:2020 Amendment 2 compliance — a pre-amendment listing did not carry over automatically.
- Specify cable sizing to AS/NZS 3008.1.1:2025 for new designs, even during the transition period.
- Recalculate DC cable sizes on unperforated trays with six or more circuits — the 2025 grouping factors are more conservative.
- Confirm battery product certifications (IEC 62619, UL 1973, UN38.3, IEC 63056 as applicable) are current, and don’t treat them as a substitute for the three installation standards above.
- Revisit this hub whenever an amendment publishes — the battery compliance stack changes faster than most single-standard guides track.
Frequently Asked Questions
What are Australia’s new battery rules?
It’s the combination of standards required for a compliant BESS installation in Australia: AS/NZS 5139 for battery system safety, AS/NZS 4777.2 for inverter/grid-connect performance, and AS/NZS 3008.1.1 for cable selection. A project needs all three — passing one doesn’t clear the others.
When did AS/NZS 5139 Amendment 1 and AS/NZS 3008.1.1:2025 take effect?
Both were published on 19 December 2025. NSW guidance treats the 5139 update as mandatory immediately on publication. Western Australia’s Building and Energy division has set 19 June 2026 as the date full compliance is required for both standards, following a six-month transition period. Confirm the position with your specific state regulator, since implementation timing is not uniform nationally.
Does every battery inverter need CEC approval in Australia?
Grid-connected inverters used in eligible Australian installations generally require approval through the Clean Energy Council’s approved inverter list, and that listing must reflect AS/NZS 4777.2 Amendment 2 compliance specifically — pre-August-2025 listings did not carry over automatically.
Are IEC 62619 or UL 1973-certified batteries automatically approved for use in Australia?
No. These certifications demonstrate battery product safety, but the complete BESS system still needs to separately satisfy AS/NZS 5139 installation compliance, AS/NZS 4777.2 inverter compliance, and AS/NZS 3008.1.1 cable design compliance.
What standard covers BESS cable sizing in Australia?
AS/NZS 3008.1.1:2025 provides current-carrying capacity, voltage drop, and derating guidance for AC and DC cables, including the new tables for DC systems up to 1500V introduced in the 2025 edition.
Further Reading
- Changes to the Battery Standard — NSW Government
- Updated Electrical Installation Standards for Battery Systems and Cable Selection — WA Government (Building and Energy)
- AS/NZS 4777.2 Inverter Standards Change — Clean Energy Council
- AS/NZS 3008.1.1:2025 Updates for Solar Cable Design — GSES
- AS/NZS 5139:2019 (incorporating Amendment 1) — Standards Australia Store
- BESS Short Circuit Protection
- PCS Overvoltage Protection
- LVRT and HVRT Ride-Through
- Understanding BESS Specifications
- VEU Rebate for Victoria: What the Program Actually Covers in 2026
Earthing (Grounding) for a Battery Energy Storage System (BESS): A Complete Design Guide
A BESS grounding system ties every battery rack, enclosure, and steel structure back to a common earth point. So, when a fault happens, current gets a fast path home. But get the BESS grounding system wrong, and one insulation fault can turn a cabinet into a shock hazard. It can also start a slow fire risk. So this guide covers the earthing methods, code rules, and design steps that keep a battery storage site safe. First, it covers soil testing. Then it covers ground grid sizing.
| Quick Answer A BESS grounding system bonds every metal part of a battery storage site to a common earth reference. Earthing is the term IEC-based countries use. Grounding is the U.S. term. But both mean the same thing. In the U.S., NEC Article 706 sets the rules for systems above 50V AC or 60V DC. Meanwhile, most other countries follow IEC 60364 instead. That standard defines TN, TT, and IT earthing systems. Also, a strong BESS grounding system needs a buried grounding electrode system. Many modern DC buses add high-resistance grounding too. So an insulation monitoring device watches for faults, instead of a solid ground wire alone. |
Why a BESS Grounding System Matters
Grounding is not paperwork. Instead, it decides whether a fault trips a breaker in milliseconds. Or, it decides whether a fault energizes a cabinet a technician is standing next to. A BESS site packs high fault current into a small footprint. Also, workers open enclosures often for maintenance. So the margin for error stays thin.
Personnel Safety
A bonded enclosure stays close to earth potential during a fault. But without that bond, a failure inside a battery cabinet can raise the metal casing to a dangerous voltage. Then anyone touching it completes the circuit. So this is the core safety case behind every BESS grounding system, at any project size.
Equipment and Fire Protection
A fast, low-impedance fault path lets breakers clear a ground fault quickly. Otherwise, the fault can grow into an arcing fault. And arcing near lithium-ion cells is a real ignition risk.
Our BESS short-circuit protection guide covers that risk in detail. So a sound BESS grounding system and short-circuit protection work as one safety strategy, not two separate items.
Protective-Device Coordination
Relays and fuses only work as fast as the fault path allows. But a weak ground path slows fault detection down. As a result, a fault can stay energized far longer than planned. So grounding design and protection coordination need to be solved together.
Earthing vs. Grounding: Same Idea, Different Vocabulary
Earthing and grounding name the same practice. First, IEC-based markets say earthing. That includes the UK, the EU, Australia, and most of Asia. Then, NEC-based markets say grounding. The United States is the main example. Still, both terms mean bonding conductive parts to earth for safety. So this guide uses both terms, matching whichever code applies to a given project.
Codes and Standards Behind a BESS Grounding System
No single global code covers earthing for battery storage. Instead, a BESS grounding system usually has to satisfy several overlapping standards. So the table below summarizes the main ones.
| Standard | Region | What It Covers |
|---|---|---|
| NEC (NFPA 70) Article 706 | United States | Covers permanently installed ESS above 50V AC or 60V DC. Sets bonding, disconnect, and circuit-protection rules |
| IEC 60364 | International | Defines TN, TT, and IT earthing system classes for low-voltage installations |
| IEEE Std 80 | International reference | Guide for AC substation grounding. Sets step- and touch-voltage limits for larger ground grids |
| IEEE Std 142 (Green Book) | International reference | General power-system grounding practice, covering equipment and system grounding |
| NFPA 855 | United States | ESS siting and spacing, which pairs with grounding design |
For example, NEC Article 706 sets the U.S. baseline for a BESS grounding system. Also, our NFPA 855 guide covers the fire-code side of siting and spacing. Meanwhile, lightning protection sits alongside a BESS grounding system, not inside it. We cover that later in this guide.
NEC Article 706’s scope line matters most for design choices. So it applies to any permanently installed ESS above 50V AC or 60V DC. That covers nearly every commercial and utility-scale BESS grounding system built today.
Types of Earthing Systems in a BESS Grounding System
TN, TT, and IT Systems (IEC 60364)
IEC 60364 uses a two-letter code for each earthing system. First, the first letter shows how the source relates to earth. Then, the second shows how equipment is earthed. TN systems bond equipment to the source’s earthed neutral. So that gives fast fault clearance through ordinary breakers. TT systems instead use a separate, independent earth electrode at the site. They rely on residual-current devices to catch smaller faults. IT systems isolate the source from earth, or use high impedance instead. So this favors continuity of supply over instant clearance. It is a common choice for critical DC sections.
See this IEC 60364 earthing system overview for the full classification breakdown.
Solidly Grounded, Ungrounded, and High-Resistance Grounded DC Buses
The battery-side DC bus needs its own decision, separate from the AC earthing system. First, older, PV-derived designs often grounded the DC bus solidly. Then a ground-fault detector-interrupter opened the bond on a fault. Today, many modern, transformerless power conversion systems instead run the DC bus ungrounded or high-resistance grounded. So an insulation monitoring device watches it continuously, instead of a fuse-based interrupter. The table below compares all three approaches.
| Approach | Fault Detection | Typical BESS Use |
|---|---|---|
| Solidly grounded | Fast — an overcurrent device clears the fault path directly | Legacy PV-battery hybrids, some low-voltage residential or C&I designs |
| Ungrounded (floating) | Continuous insulation-resistance monitoring, no automatic first-fault trip | Modern transformerless PCS topologies where uptime matters most |
| High-resistance grounded | Limits fault current while a monitoring device flags the fault | Utility-scale strings and central PCS designs balancing safety and uptime |
This choice depends heavily on PCS topology. So it belongs in the same conversation as PCS overvoltage protection and grid-forming versus grid-following control. It should never be bolted on after the fact.
Core Components of a BESS Grounding System
Equipment Grounding and Bonding in a BESS Grounding System
Every metal enclosure, rack, and structural part needs a bonding jumper. That jumper must reach back to the grounding system. Also, it needs to be sized for the worst-case fault current. First, painted surfaces need a bare-metal bonding point, since paint is an insulator. Also, fence gates and conduit expansion joints need flexible jumpers, so thermal movement never breaks continuity.
Conductor size follows the code, not a guess. So the table below gives quick reference points for both major code families.
| Reference | Basis | Quick Rule |
|---|---|---|
| NEC Table 250.66 (GEC sizing) | Size of the largest ungrounded service conductor | A GEC run solely to a rod, pipe, or plate electrode never needs to exceed 6 AWG copper |
| NEC Table 250.122 (EGC sizing) | Rating of the upstream overcurrent device | Equipment grounding conductors scale with breaker or fuse size, not with the circuit conductor size |
| IEC 60364-5-54 (PE sizing) | Cross-sectional area of the phase conductor | PE equals the phase size up to 16 mm², stays at 16 mm² up to 35 mm², then drops to half the phase size above that |
The Grounding Electrode System
This is the buried hardware that gives fault current a path into the earth. It can be ground rods, a ground ring, or a full mesh grid. So, site size drives the choice. First, a small C&I rooftop or pad-mounted BESS can use a simple rod-based electrode system. Then, a utility-scale site instead needs a buried copper mesh grid. That grid must meet IEEE 80 step- and touch-voltage limits.
Grounding a Containerized or Mobile BESS
Containerized and trailer-mounted BESS units add a wrinkle. Often, they sit on gravel, asphalt, or a temporary pad, not poured concrete. So a concrete-encased electrode is rarely an option there. Instead, crews drive temporary ground rods, or lay a portable ground mat, at each deployment site. Also, every container or trailer section needs a bonding strap back to that temporary electrode, plus jumpers between linked sections. Since soil conditions change from site to site, resistance needs a fresh test at every new location, not just once back at the factory.
DC Ground-Fault Detection and Insulation Monitoring
On the DC side, ground-fault detector-interrupters and insulation monitoring devices solve the same problem in different ways. Both catch a fault between a live conductor and ground before it becomes an arc. Also, an insulation monitoring device measures leakage resistance continuously. So it raises an alarm well before resistance drops to a dangerous level. That is why it has become the default choice on ungrounded and high-resistance grounded DC buses.
Avoiding Ground Loops in a BESS Grounding System
Power grounding is not the only ground reference on a BESS site. Comms wiring also needs care. That includes CAN bus, RS-485, or IEC 61850 links between racks, the BMS, and the PCS. So a shielded comms cable should bond to ground at one end only. Otherwise, bonding both ends creates a ground loop. Then, even a small voltage difference between the two ground points drives current through the shield. That current, in turn, induces noise onto the signal pair. Common symptoms include noisy cell-voltage readings, checksum errors, and comms dropouts, especially during heavy charge or discharge events. So plan single-point grounding for comms at design time, not after commissioning turns up faults.
Designing a BESS Grounding System’s Electrode Network
Soil Resistivity Testing
Soil resistivity, not conductor size, drives ground rod performance the most. It shifts with moisture, temperature, and soil type. So a resistivity survey should happen early in site design, not after the rods are already buried. The four-pin Wenner method is the standard test. Also, sandy or rocky soil can carry resistivity several times higher than loam. That directly raises the rod count, the grid area, or the need for ground-enhancement material.
The Concrete-Encased Electrode (Ufer Ground)
Most C&I and utility-scale BESS pads already sit on poured concrete. So that concrete can double as a grounding electrode. NEC 250.52(A)(3) allows this. A concrete-encased electrode, often called a Ufer ground, uses at least 20 feet of rebar or bare copper conductor, encased in at least 2 inches of concrete that touches the earth. Since a Ufer ground typically beats a driven rod on resistance, especially in dry or rocky soil, it is worth planning before the pour, not after. Once the concrete cures, adding one later means breaking into a finished pad.
Worked Example: Sizing Ground Rods for a C&I BESS Pad
Take a standard 8-foot, 5/8-inch copper-clad ground rod. Place it in average loam soil, with a resistivity of 100 Ω·m. Using the standard single-rod resistance formula, that rod works out to roughly 40 Ω. So that is above the 25 Ω threshold NEC 250.53(A)(2) sets for a single rod, pipe, or plate electrode. Then, a second rod, spaced at least 6 feet away, usually brings the combined resistance under that 25 Ω limit. But mutual interference between rods means the drop is never a clean 50%. In high-resistivity ground — sandy or rocky soil at 300 Ω·m or more — a single rod can exceed 100 Ω. There, the fix shifts from adding rods to a driven ground ring, chemical rods, or ground-enhancement backfill.
Step and Touch Voltage for Utility-Scale Sites
Larger sites need more than a resistance number. So IEEE Std 80 sets tolerable step- and touch-voltage limits. These depend on soil resistivity, fault-current size, and clearing time. Then, the standard works backward to the mesh spacing a ground grid needs. Still, a grid can show low overall resistance and still fail an IEEE 80 check. That happens when the voltage gradient across the grid surface runs too steep. So resistance alone is never the full design target for a utility-scale BESS grounding system.
See this IEEE Std 80 grounding interpretation for the underlying safety criteria.
Lightning Protection Sits Alongside Earthing
Lightning protection systems use their own down-conductor and electrode network. NFPA 780 covers this in the U.S. IEC 62305 covers it internationally. So this network is engineered for high-frequency surge current. It stays distinct from the power-system grounding electrode system. Still, the two networks are typically bonded together at grade. That prevents a dangerous potential difference between them during a strike.
Surge protective devices on the AC and DC sides, covered in our PCS overvoltage protection guide, round out the site’s full surge coordination plan.
Common BESS Grounding System Mistakes
- Treating a painted enclosure surface as a bonding point, instead of scraping to bare metal first.
- Installing a single ground rod without testing resistance, then assuming it clears the NEC 25 Ω threshold.
- Skipping flexible bonding jumpers across fence gates and conduit joints, which breaks continuity as materials move.
- Solidly grounding a DC bus on a transformerless PCS without checking manufacturer guidance, which can cause nuisance trips.
- Sizing a ground grid to a resistance target alone, with no IEEE 80 step- and touch-voltage check on a utility-scale site.
- Bonding bare copper directly to galvanized steel rebar or racking in humid or coastal soil, which speeds up galvanic corrosion at the connection point.
- Never re-testing soil resistivity or ground resistance after commissioning, even though seasonal moisture changes both.
Key Takeaways
- A BESS grounding system bonds every conductive part to a common earth reference. That gives fault current a defined, low-impedance path home.
- NEC Article 706 governs U.S. installations above 50V AC or 60V DC. IEC 60364’s TN, TT, and IT classes govern most other markets.
- Many modern, transformerless PCS designs run the DC bus ungrounded or high-resistance grounded. An insulation monitoring device watches it instead of a solidly grounded fuse-based interrupter.
- A single ground rod in average soil rarely meets NEC’s 25 Ω threshold alone. Test soil resistivity before the rods go in the ground, not after.
- A poured concrete BESS pad can double as a Ufer ground under NEC 250.52(A)(3), often beating a driven rod on resistance in dry or rocky soil.
- Keep comms shields single-point grounded. Bonding both ends of a CAN bus, RS-485, or IEC 61850 shield creates a ground loop that shows up as noisy readings and comms dropouts.
- Utility-scale sites need an IEEE 80 step- and touch-voltage check. A low resistance reading alone does not guarantee a safe voltage gradient.
- Lightning protection and power-system grounding are separate networks. Bond them together at grade; do not treat them as one system.
- Grounding design, short-circuit protection, and overvoltage protection form one coordinated safety strategy, not three separate checklists.
Frequently Asked Questions
Does the NEC Require a BESS Grounding System?
Yes. For any permanently installed ESS above 50V AC or 60V DC, NEC Article 706 sets bonding, disconnect, and circuit-protection rules. These form the core of a compliant BESS grounding system.
What Ground Resistance Does a BESS Grounding System Need?
The NEC benchmark for a single rod, pipe, or plate electrode is 25 Ω or less. If one rod misses that mark, add a supplemental rod at least 6 feet away. Utility-scale sites also need an IEEE 80 step- and touch-voltage check, on top of a lower target resistance.
Should a BESS DC bus be grounded or ungrounded?
It depends on the PCS topology. Many modern, transformerless designs use an ungrounded or high-resistance grounded DC bus with continuous insulation monitoring. Some legacy or transformer-based designs still solidly ground the bus with a ground-fault detector-interrupter. Follow the PCS manufacturer’s guidance rather than a default assumption.
Does a Containerized or Mobile BESS Need Different Grounding?
Yes, somewhat. A fixed pad lets a BESS grounding system use a concrete-encased electrode. A mobile or trailer-mounted unit usually cannot rely on that. So it needs temporary ground rods or a portable ground mat at each site, plus fresh resistance testing every time it moves.
How often should a BESS grounding system be tested?
Test ground resistance and bonding continuity at commissioning first, using a fall-of-potential test or a clamp-on ground resistance tester. Then, re-test on a regular maintenance schedule. Soil resistivity shifts with seasonal moisture and temperature, so a compliant reading at commissioning can drift over time.
Further Reading
- BESS Short Circuit Protection
- PCS Overvoltage Protection
- Understanding BESS Specifications
- NFPA 855 Guide
- LVRT and HVRT Ride-Through
- Grid-Forming vs. Grid-Following BESS
- BESS PCS Functions and Features
- NEC Article 706 overview (up.codes)
- IEEE Std 80 substation grounding interpretation (standards.ieee.org)
- IEC 60364 earthing system classification overview (ecalpro.com)