When we sit down with a new customer to design their solar system, one of the first things we check is whether their home is on single phase or three phase power. It’s a question that shapes every decision that follows – inverter choice, battery options, EV charging capability and how much the system can grow in the future.
Most homeowners have never needed to think about this before. Here’s what you need to know…
What’s the Difference?
The electricity grid delivers power to your home through alternating current (AC) that cycles at 50Hz. Single phase power delivers this through one active wire. Three phase power delivers it through three active wires, each offset by 120 degrees, which together provide a smoother, more capable power supply.
In practical terms:
- Single phase is standard in most Australian homes, particularly older and smaller properties
- Three phase is common in larger homes, newer estates, and most commercial properties
- Single phase is limited to a maximum continuous supply of around 63 amps, while three phase can supply significantly more (roughly three times more)
You can check which supply you have by opening your switchboard. Single phase will have one main circuit breaker and fuse. Three phase will have three, typically grouped together or visible as a three-pole breaker.
Why Does It Matter for Solar?
Single phase and three phase homes can both run solar panels and batteries without any issues. The difference shows up in three specific areas.
Inverter sizing. Single phase inverters in NSW are generally limited to 5kW or 10kW export capacity under network rules (though systems can be designed larger with export limiting). Three phase homes can export across all three phases simultaneously, making larger systems more straightforward to approve and connect.
Battery integration. Most modern battery systems – Sungrow SBR, AlphaESS SMILE, Sigenergy SigenStor – work on both single and three phase. However, on a three phase home, three phase backup power during a blackout can be configured to cover all three phases, giving you more flexibility about which circuits stay live when the grid goes down.
EV charging. This is where three phase starts to shine noticeably. A three phase EV charger can deliver up to 22kW of charging power, compared to around 7kW on single phase. If you’re planning to charge an EV from solar, three phase gives you a significantly larger window to capture solar generation during the day if your EV can accept it.
Can You Upgrade from Single Phase to Three Phase?
Yes – but it’s not a simple job. Upgrading requires an application to your local distribution network service provider (DNSP), a licensed electrician to run new cabling from the street, and a new meter installation. It’s a worthwhile upgrade for homes planning a large solar system, a battery, and an EV charger, but it adds time and cost to the project.
We always assess whether an upgrade makes sense for your situation before recommending it. For many single phase homes, a well-designed solar and battery system works perfectly without any upgrade at all.
What We Recommend
If you’re on single phase and planning solar only, or solar plus a battery, you’re unlikely to need a three phase upgrade. Single phase solar systems are efficient, well-supported by all the brands we install, and approved quickly by local networks.
If you’re on single phase and planning to add an EV charger now or in the next few years, it’s worth having a conversation about three phase before you commit. Upgrading later costs more than planning for it upfront.
If you’re already on three phase, you’re in a strong position. We’ll design a system that takes full advantage of what three phase offers.
Not Sure Which You Have?
That’s completely normal – most homeowners don’t know offhand whether they have Single Phase vs Three Phase power. When you call us for a quote, we’ll confirm your supply type as part of the site assessment. It takes about 30 seconds to check and it shapes everything that follows.
Call us on 0479 170 789 or get in touch at iconicsolar.com.au and we’ll sort it out from there.