In this guide
Ask two different Perth solar companies where your battery can go, and you might get two different answers — not because either is wrong, but because “the rules” for a WA battery installation actually come from two completely separate places. One governs where the physical unit is allowed to sit on your wall. The other governs how it connects to the grid. A system can satisfy one and still fail the other. This guide covers both properly, including a genuine regulatory change taking effect on 1 May 2026 that most existing content hasn’t caught up with yet.
Two Separate Rulesets, Not One
Placement — AS/NZS 5139
- Governs the physical location of the battery on your property
- Clearances, ignition source separation, mounting surface
- Applies to every grid-connected battery, regardless of brand or size
Connection — Western Power’s WEM Procedure
- Governs how the system connects to and communicates with the grid
- New requirements from 1 May 2026 for new or upgraded systems
- Determines your export options, not where the unit is mounted
An installer can nail one of these and get the other wrong — usually not from carelessness, but because they’re genuinely different disciplines: one is closer to fire safety and electrical installation practice, the other is closer to network engineering. This guide takes them in that order: where the battery goes, then how it connects.
AS/NZS 5139: Where a Battery Is Legally Allowed to Go
Every grid-connected battery in Australia has to comply with AS/NZS 5139:2019, the standard governing installation and safety for battery energy storage systems. It sets out clearance distances, ignition source separation, mounting surface requirements, and — critically — a list of locations a battery simply isn’t allowed to occupy, regardless of how convenient they might seem.
Clearance Requirements
The standard sets out several distinct clearance types, each serving a different purpose — surface clearance for heat dissipation, a working space for service access, and separation from anything that could act as an ignition source.
| Clearance type | What it’s for |
|---|---|
| Above, sides, below the unit | Airflow for cooling — smaller figures, typically well under 300mm depending on the specific requirement and battery model |
| In front of the unit | 600mm minimum — service access for maintenance and emergency response |
| From gas meters and regulators | Around 1.5m — ignition source separation |
| From gas appliance flues | Around 1m |
| From switchboards and AC units | Roughly 0.5–0.6m |
| From openable windows and exit doors | 600mm minimum |
Worth knowing: exact clearance figures vary between sources
Different clearance categories genuinely get reported differently across installer guides — surface-level clearance for cooling is smaller than the working space required in front of the unit for service access, and it’s easy for these to get conflated into a single figure. The table above reflects the clearance types the standard addresses; the precise millimetre figure for your specific battery model depends on the manufacturer’s installation manual, which can specify tighter or looser requirements than the standard’s general minimums. This is exactly what a proper site assessment confirms — not something to measure yourself off a general guide.
Mounting surface matters too: brick, concrete and masonry are compliant without further work. A timber-framed wall needs a fire-rated, non-combustible backing board — commonly cement sheeting — installed behind the unit first.
Locations That Are Ruled Out Entirely
Some placements aren’t a matter of clearance distance — they’re prohibited outright.
- Habitable rooms. Bedrooms, living rooms, kitchens, and any regularly occupied space are off-limits under AS/NZS 5139, full stop.
- Escape routes and stairwells. A battery can’t obstruct an evacuation path, including a hallway leading to an exit.
- Ceiling cavities and under stairs. Heat build-up in one case, escape-path obstruction in the other.
- Enclosed, unventilated spaces. Even a garage needs adequate ventilation — most achieve this through the roller door gap, but a fully sealed space needs an actual vent.
- Near flammable material storage. Paint, fuel containers, and timber stacks need to stay clear of the unit.
Perth Climate Considerations
The standard sets the legal minimum. Perth’s climate adds a practical layer on top of it that’s worth factoring in even where the standard doesn’t strictly require it.
Heat and wall orientation
- Batteries operate best in a moderate temperature range — sustained heat above roughly 40°C accelerates degradation
- Perth regularly exceeds 35–38°C from November to March, and a west-facing wall in direct afternoon sun runs hotter again
- A south or east-facing wall, or inside the garage, generally runs cooler than a west-facing external wall
Coastal exposure
- Homes within roughly 1km of the coast — think Cottesloe, Scarborough, or the Fremantle foreshore — face genuinely faster corrosion risk on external metalwork
- Marine-grade or additional corrosion protection is worth discussing with your installer for these locations specifically
- An IP65 or higher external rating handles Perth’s dust, insects, and occasional driving rain regardless of location
None of this changes what’s legally required — it’s the difference between a compliant install and one that also accounts for how a Perth summer actually behaves.
The December 2025 Amendment: What Actually Changed
AS/NZS 5139’s Amendment 1 became mandatory on 19 December 2025. It doesn’t replace the 2019 standard — it updates specific clauses within it, and the change most relevant to placement decisions is a new exception for garage door openings.
The garage-door exception
Previously, the standard’s general 600mm clearance from any exit — including a garage door — made placement near that opening difficult in smaller garages. The amendment adds a specific exception: a battery can be installed within 600mm of a garage door opening, provided the opening itself is wider than 900mm and safe walk-through clearance of at least 1m is maintained from the front or side a person would need to pass. Both conditions need to be met, not just one.
If you’ve read older advice suggesting garages were effectively unworkable near the door without extensive re-planning, this is worth revisiting — the practical answer changed in December 2025, even though the underlying standard’s edition number didn’t.
The New Grid Connection Rules From 1 May 2026
This is a separate, more recent change — and a genuinely significant one. From 1 May 2026, new or upgraded solar and battery systems on WA’s South West Interconnected System (SWIS) need to meet updated technical requirements set out in Western Power’s WEM Procedure, covering what the network calls “Standard Small User Facilities” — broadly, any connection under 1000V with a combined system capacity of 30kVA or less, which covers the overwhelming majority of homes.
WA’s SWIS is the largest genuinely isolated electricity grid in the world — it isn’t connected to any neighbouring state’s network the way most of the eastern seaboard is. That isolation, combined with the sheer volume of rooftop solar now feeding into it, is the practical reason behind the change: the system operator needs a more coordinated way to manage export from hundreds of thousands of individual homes without risking local network stability.
The Two Export Pathways
The practical part for homeowners isn’t a new blanket restriction — it’s a choice between two ways a system can be set up.
Standard export
- Fixed 1.5kW export limit
- No ongoing communications requirement after installation testing
- Simplest option if your inverter location has unreliable internet, or you’re not interested in future flexible export products
Flexible / future-ready export
- System is communications-capable, commissioned via CSIP-AUS for Synergy customers
- Supports future participation in dynamic exports and VPPs as those products roll out
- Requires a stable connection at the inverter’s location — commonly Wi-Fi
Neither path is inherently better — it depends on whether you value the simplicity of a fixed setup or want the system future-proofed for products that aren’t fully available yet. If communications drop after a flexible setup is running, the system doesn’t fail or get penalised — it defaults to a lower static export limit until the connection is restored, then automatically resumes flexible capability.
What This Means If You Already Have Solar
The new requirements apply going forward, not retrospectively — but the definition of “going forward” catches more people than it might first appear to.
- System installed and commissioned before 1 May 2026, no changes planned: nothing changes. You continue under the rules that applied when it was installed.
- Adding a battery to existing solar, on or after 1 May 2026: this counts as an upgrade, which means the new requirements apply to that work — even though the original solar installation predates the change.
- Like-for-like warranty inverter replacement: generally exempt from the new requirements on an ongoing basis.
- Older inverters that can’t be firmware-updated to communicate: a gateway device can usually bridge the gap — available for most existing inverter models on the market.
If you’re already planning to add a battery to an existing system, this is a genuine reason to raise the timing and the export-pathway choice directly with your installer before the job is scheduled, not after.
Get a site assessment that covers both rulesets
Placement and grid connection, checked together — not as two separate conversations after the job’s already underway.
Get a free assessmentExplore More Solar Red Guides
FAQ
- Can I install a solar battery in my garage in Perth?
- Yes, and it’s the most common placement for Perth homes — natural weather protection, cooler than an external wall in summer, and usually close to the switchboard. It still needs to meet AS/NZS 5139 clearance requirements and can’t obstruct the garage as an escape route.
- How close can a solar battery be to a window or door?
- AS/NZS 5139 generally requires at least 600mm clearance from openable windows and exit doors. A December 2025 amendment added a specific exception for garage door openings wider than 900mm, allowing closer placement provided safe walk-through clearance of at least 1m is maintained.
- What are the new WA solar and battery rules from May 2026?
- From 1 May 2026, new or upgraded systems on WA’s SWIS need to support updated grid connection standards, commissioned via CSIP-AUS for Synergy customers. Homeowners choose between a standard 1.5kW static export limit with no ongoing communication requirement, or a communications-capable setup enabling future flexible exports and VPP participation.
- Do the new May 2026 rules apply to my existing solar system?
- No. The new requirements only apply to systems installed or upgraded on or after 1 May 2026. If your system predates that and isn’t being upgraded, you continue under the rules that applied when it was installed.
- Does adding a battery to my existing solar count as an upgrade under the new rules?
- Yes. Adding a battery, or adding or changing an inverter, counts as an upgrade, so the requirements taking effect 1 May 2026 apply to that work, even though the original solar installation predates the change.
- Can I put a solar battery in my bedroom or living room?
- No. AS/NZS 5139 prohibits battery installation inside habitable rooms — bedrooms, living rooms, kitchens, and any regularly occupied space — and it can’t be installed along an escape route or evacuation path either.
- What happens if my internet drops out after choosing the flexible export pathway?
- The system isn’t penalised. It automatically defaults to a lower static export limit while communications are down, then resumes flexible export capability once the connection is restored.
- Can I install a battery myself to save money?
- No. Grid-connected battery systems must be installed by a licensed electrician holding SAA battery accreditation. DIY installation of a grid-connected battery is illegal in Australia, and it would void your warranty, your home insurance, and any rebate eligibility.
