New WA Solar Installs — What To Check Before Signing A Quote

From 1 May 2026, new inverter rules apply to solar and battery systems connected to WA’s main electricity grid, managed by Western Power.

Your installer is responsible for making sure your system meets the technical requirements – that’s their job. But there are two things worth discussing with them: how your export limits are configured and whether your system has room to grow.

This guide covers what to look for under the new rules. It’s not general solar buying advice – it’s specifically about new design decisions that matter because of the new rules.

What Changes For New Installations?

The main change for new solar and battery systems in WA is that all inverter capacity is now counted as a single combined total under a 30 kVA¹ limit. This affects how systems are designed from the outset, particularly where solar and battery inverters are installed together or where future expansion is being considered.

New systems must also meet updated export requirements, with either a fixed 1.5 kW export limit or remote export control under network management requirements set by Western Power.

What To Check Before Signing

System Size

If you’re getting quotes under the new rules, what matters is how your system’s total inverter capacity is counted. Under the 30 kVA aggregate limit, all inverter capacity on the property is added together, including both solar and battery inverters.

In AC-coupled designs, solar and battery systems use separate inverters, so each contributes to the total.

For example, a 25 kW solar inverter would only leave 5 kW for the battery inverter. That would take 5 hours to charge a 25 kWh battery, no matter how strong the sun was shining.

In a DC-coupled hybrid system, both functions run through a single inverter, so a 25 kW hybrid inverter system would allow 25kW² of solar panels and could charge a 25 kWh battery in one hour.

Export Limits

You should also confirm how export limits will be set up. Some systems will operate under a fixed 1.5 kW export cap, while others will use remote export control, where exports can be adjusted by the network depending on system conditions.

Fixed exports are easier to configure and understand, but flexible exports will export more, so they are more lucrative, as long as you are getting paid a feed-in tariff.

System Expansion

It’s also important to understand how much room your system leaves for future upgrades. Under the 30 kVA combined inverter limit, any additional inverter capacity – including a battery added later – still counts toward the same total allowance.

As noted earlier, AC-coupled systems use separate inverters for solar and batteries, so adding a battery later will use more of that available capacity. If most of it has already been used, there may be little room left without replacing existing equipment.

Systems built around a single hybrid inverter don’t require a second inverter for storage, which can make future expansion easier within the same overall limit. But you do need to be confident that compatible batteries will still be available when you are ready to buy them.

It is important to realise that the limit is not per-phase. If you’ve got 3-phase you are still limited to 30 kVA total.

Do Existing Solar Systems Need To Change?

Existing systems are not affected unless they are modified or upgraded, but any change – including adding battery capacity or increasing inverter size – will trigger reassessment under the updated 30 kVA combined inverter framework.

Avoiding Design Headaches Later

Getting the design decisions right at the quote stage – inverter sizing, export settings, and allowance for future expansion – is what helps avoid headaches later. Once installed under the 30 kVA framework, changes can be limited and may require redesign rather than simple upgrades. That’s why the detail in the initial quote matters just as much as the equipment itself.

More information on connection requirements and processes is available via the SolarQuotes WA solar connection rules and processes guide page.

For practical tips on assessing solar quotes, see our guide on getting and comparing solar quotes.