When homeowners think about solar battery safety, they usually think about fire risk from the battery itself — a legitimate concern and one that good brands like BYD and Sungrow take seriously. But there is a second risk that almost nobody talks about: the wiring behind the wall.
Across New South Wales, a significant number of solar battery installations are wired incorrectly. Not badly — incorrectly. There is a specific Australian Standard that governs how batteries must be wired into your home, and many homeowners have no idea it exists, let alone whether their own installer followed it.
This article explains what the standard is, what it requires, and the three questions you should ask any installer before you sign anything.

The Standard You Have Never Heard Of: AS/NZS 3000:2018
Australian electrical installations — including solar battery storage systems — are governed by AS/NZS 3000:2018, commonly known as the Wiring Rules. Every licensed electrician in NSW is legally required to follow it. The problem is not that the standard does not exist. The problem is that nobody tells homeowners about it, which means nobody thinks to check.
In 2019, the standard was updated with a companion document specifically for battery energy storage systems: AS/NZS 5139:2019. Together, these two documents set out exactly how a battery must be wired — from the cable sizing, to the isolator placement, to the earthing arrangement — to be considered safe and compliant.
What these standards actually require: A dedicated circuit for the battery, correctly sized DC and AC cables, a properly rated DC isolator between the battery and inverter, correct earthing and bonding, and a Certificate of Compliance issued by a licensed electrician before handover.
Why Most Homeowners Miss It
The solar and battery industry in NSW has grown rapidly. With that growth has come pressure on installers to move quickly, keep costs low, and compete on price. In that environment, some corners get cut — and wiring compliance is one of the first places shortcuts appear.
Here is what non-compliant wiring typically looks like in practice:
- The installation connects the battery to an existing circuit that already serves other loads, instead of using a dedicated run
- The cable used is undersized for the continuous discharge current of the battery — creating heat at the cable over time
- The DC isolator is missing, poorly placed, or not rated for the battery’s voltage and current
- No Certificate of Compliance is issued after the install — meaning there is no official record that the work meets the standard
None of these shortcuts are visible once the wall is closed. You would not know. Your installer might not even acknowledge the issue. But your insurer might — particularly if something goes wrong.
The Insurance Problem Nobody Warns You About
Home insurance policies in Australia typically contain a clause that voids coverage for damage caused by non-compliant electrical work. If your battery is wired incorrectly and causes a fire or electrical fault, your insurer can — and in some cases will — refuse to pay.
The risk is not just theoretical.
NSW Fair Trading and the Clean Energy Regulator have both received complaints about battery installations that failed inspection or caused issues after handover. In most cases, the homeowner had no idea the installation was non-compliant until the problem emerged.
This is not about fearmongering. The vast majority of battery installations are done correctly. But a ‘mostly fine’ installation rate is not the same as a ‘yours is definitely fine’ guarantee. Given that a compliant install and a non-compliant install often look identical from the outside, the only way to know is to ask the right questions before you sign.

The Three Questions to Ask Any Installer
You do not need to become an electrician to protect yourself. These three questions will quickly tell you whether an installer knows their obligations — and whether they are willing to meet them.
Question 1: Which wiring standard governs battery installations in NSW?
The correct answer is AS/NZS 3000:2018 (the Wiring Rules) and AS/NZS 5139:2019 (the battery-specific standard). An installer who cannot name either document — or who looks uncertain — is a red flag. This is not obscure knowledge. It is the legal foundation of their work.
Every licensed installer in NSW should hold current accreditation. You can verify your installer’s accreditation here before you agree to anything — it takes less than a minute and gives you immediate peace of mind.
Question 2: Will you provide a Certificate of Compliance after installation?
This certificate, sometimes called a Certificate of Compliance for Electrical Work (CCEW), is issued by a licensed electrician to confirm that the installation meets the required standard. It is not optional. If an installer says they do not usually provide one, or that you can request it separately, be cautious. It should be offered as standard.
Question 3: Will the battery have its own dedicated circuit?
A compliant battery installation requires a dedicated circuit — not a circuit shared with other appliances or with your existing solar setup. If the answer is vague or the installer suggests they will reuse existing wiring, that is a flag worth exploring further before proceeding.

A Note on NSW VPP Incentives and Compliance
If you plan to participate in a Virtual Power Plant (VPP) to access the NSW VPP battery incentive — which can add up to $1,500 on top of the federal rebate — you must ensure your battery installation passes a network assessment before enrollment.
That assessment includes a review of how the system is wired. If your installation doesn’t meet AS/NZS 3000 or 5139 standards, it won’t pass the network check. A simple wiring shortcut could end up costing you the entire incentive If you want to understand more about how the VPP incentive works in NSW, this guide to the NSW VPP battery incentive explains the full requirements and eligibility process.
What a Compliant Installation Includes
To be clear about what you should expect from a professional battery installation in NSW. Here is what the standards require:
- A dedicated battery circuit, separate from all other household wiring
- AC and DC cables sized correctly for the battery’s continuous discharge current
- A DC isolator installed between the battery and inverter, rated for the system voltage
- Correct earthing and bonding in line with AS/NZS 3000:2018
- Battery location meeting the clearance and ventilation requirements of AS/NZS 5139:2019
- A Certificate of Compliance issued by the licensed electrician who performed the work
None of this is expensive or time-consuming when done from the start. The problem only arises when an installer tries to save time by skipping steps — and the homeowner does not know what to ask.
The Honest Bottom Line
Solar batteries are safe when installed correctly. The Australian standards exist precisely because someone — or many someones — worked out what ‘correctly’ looks like in detail. They are not bureaucratic box-ticking. They are the engineering consensus on what a battery installation needs to look like to be reliably safe over its working life.
The single most effective thing you can do as a homeowner is ask the three questions above before you sign. A good installer will answer them clearly and confidently. A poor installer will not.
Ask anyway. The answer will tell you everything you need to know.
Get a Compliant Battery Installation Quote Today
Solar Battery Outlet installs to AS/NZS 3000:2018 and AS/NZS 5139:2019 as standard. Every job includes a Certificate of Compliance. No shortcuts, no excuses.
Call us on 1800 000 777 or visit solarbatteryoutlet.com.au to request your free quote.Serving NSW homeowners — fully accredited, government rebate ready.












