Three-Phase Power and Solar: What You Need to Know

In simple terms, three-phase power uses three separate electrical circuits to deliver electricity to your property. Each circuit (or “phase”) carries an alternating current that peaks at a different time, creating a smooth, continuous flow of power. Think of it like three runners on a relay team: while one rests, the other two keep moving.

Most Australian homes are connected to single-phase power at 230 volts. This is perfectly fine for standard household loads like lighting, fridges, and a few air conditioners. Three-phase power, at 400 volts across the phases, is typically found in larger homes, rural properties, homes with workshops, and all commercial and industrial premises. It handles heavier loads more efficiently and allows you to run bigger equipment without overloading any single circuit.

Not sure what you have? Open your switchboard. If you see one main switch feeding your circuit breakers, you are on single-phase. If you see three mains (often labelled L1, L2, L3), you have three-phase. Your electrician or energy distributor can confirm this in seconds.

The biggest impact is on your inverter choice. If you have three-phase supply but install a single-phase inverter, all your solar generation feeds into just one of the three phases. Appliances running on the other two phases still pull power from the grid, even while your solar is generating surplus on phase one. Your meter measures each phase independently in most cases, so you could be exporting on one phase while importing on the other two at the same time. That is money left on the table.

A three-phase solar inverter spreads your generation evenly across all three phases. This means more of your solar power is consumed on-site before any surplus gets exported. It also avoids a common problem: some distributors impose export limits per phase (typically 5kW). With a single-phase inverter on a three-phase connection, you hit that limit quickly. A three-phase inverter distributes exports across three phases, effectively tripling your export headroom.

For systems larger than 5kW, most network operators require a three-phase inverter if your property has three-phase supply. This is not just a recommendation. It is a connection requirement in many distribution areas across Australia.

If your home has three-phase supply, a three-phase inverter is almost always the right call. Here is why:

• check_circleIt distributes solar production evenly across all three phases, maximising self-consumption.
• check_circleIt avoids export limiting issues that occur when all generation sits on one phase.
• check_circleIt supports larger system sizes (10kW, 13kW, or bigger) without needing special network approval.
• check_circleMany network distributors require it for systems above 5kW on three-phase connections.

The price difference between a single-phase and three-phase inverter of the same capacity is usually modest, often just $200 to $500 more. Given the benefits, it is hard to justify going single-phase on a three-phase property.

The exception: if your property is single-phase and your solar system is 5kW or under, a single-phase inverter is the correct and only option.

Australian installers have access to several well-proven three-phase inverter ranges. Here are the ones you will see on most quotes:

Yes. Upgrading from single-phase to three-phase is a common job for electricians and your local energy distributor. The process involves running two additional cables from the street transformer to your meter, upgrading your switchboard, and having your distributor reconfigure the connection. The whole job typically takes 2 to 6 weeks including distributor approvals.

Cost is the main consideration. Expect to pay between $2,000 and $5,000, depending on your distance from the nearest transformer and your distributor's fees. In some areas, particularly rural properties where the transformer is further away, costs can run higher.

It is worth the investment if you are planning any of the following:

• boltA solar system larger than 5kW (common for families or homes with pools).
• boltAn EV charger, especially a 7kW or 22kW unit that benefits from three-phase.
• boltHeavy workshop equipment, ducted air conditioning, or large pool pumps.
• boltA future battery system where balanced phase loading improves performance.

If you are already getting solar quotes, ask your installer whether a three-phase upgrade makes sense. Many installers can coordinate the upgrade alongside your solar installation, sometimes bundling the cost into the overall project.

Not everyone needs three-phase. If your home runs a 5kW or 6.6kW solar system, you do not have an EV or pool, and your electricity consumption is under 20kWh per day, single-phase is more than adequate. The upgrade cost of $2,000 to $5,000 is hard to justify if your energy needs are modest.

The key question is whether your current supply limits what you want to do. If you are hitting the 5kW inverter cap and want a bigger system, or you are getting voltage rise issues that cause your inverter to throttle, those are signs that three-phase would solve a real problem. Otherwise, single-phase works just fine for the majority of Australian households.