If you’re deep into your research around home solar systems, then there’s a good chance you’ve stumbled across the term ‘3-phase power’ or ‘3-phase solar’. Renowned for its higher capacity, 3-phase solar may seem like the perfect fit on face value. But there are some limitations to this type of solar connection, particularly if you are looking to install solar at a residential property.
To help you distinguish which type of system would be best suited to your property, we’ve broken down the basics of a 3-phase solar system with this Canstar Blue guide.
On this page:
- What is a 3-phase power supply?
- What’s the difference between a single-phase and a 3-phase power supply?
- How do I know if I have a 3-phase power supply?
- How does a 3-phase solar system work?
- Do I need a 3-phase solar system?
- Single-phase solar vs 3-phase solar power
- How much does it cost to install a 3-phase solar system?
- 3-phase solar inverter brands
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What is a 3-phase power supply?
To understand 3-phase solar, you’ll need to be familiar with 3-phase power supplies. The power supply is the connection point that your home has to the grid and it generally comes in two forms: single and 3-phase. 3-phase, as the name suggests, uses three active wires and one neutral to transmit electricity from the grid to your appliances. In comparison, single-phase only uses one active and one neutral wire.
Single-phase power supplies are most common among residential properties in Australia, with 3-phase being reserved for larger homes and commercial properties. However, you may find some older homes will have a 3-phase power supply.
What’s the difference between 3-phase and single-phase power supplies?
The main difference between a single-phase and 3-phase power supply is the number of wires used to transmit electricity from the grid to a property. As the names suggest, a single-phase connection will use just one live wire, whereas 3-phase incorporates three active wires.
A 3-phase power supply is generally better equipped to handle bigger energy loads, as it has the capacity to draw more power from the grid due to the additional wires. This is why this connection type is more common in commercial properties that tend to consume energy at a higher capacity. But 3-phase power can be useful for homes that operate large appliances such as heaters, pool pumps, spas or electric vehicle chargers.
With a 3-phase power supply, electricity distribution is essentially divided among the three wires, meaning that certain appliances may only be powered by certain wires. For example, your dishwasher and washing machine may be powered by one supply, while your home appliances run on another. On a single-phase connection, all household power is supplied through the single wire.
How do I know if I have a 3-phase power supply?
If you are not sure what power supply your home runs on, you should be able to find this information on your electricity meter. On the meter, it should state whether you have ‘1-phase’ or ‘3-phase’ power. You can also check the number of breakers you have on your fuse box under the ‘main switch’ tab – if you have just the one, you’ll likely have single-phase power. Keep in mind that your switchboard is live with power and to avoid touching the board.
If you can’t find this information written on your meter, or you’re struggling to decipher the electrical jargon, you can also contact your energy distributor for confirmation.
How does a 3-phase solar system work?
3-phase solar systems run on a similar principle to 3-phase power, in that the system sends electricity across three wires, as opposed to one. This allows the system to minimise the risk of voltage issues and triple the solar power supply being sent to appliances (or the grid), and to run at a higher efficiency and capacity.
A 3-phase solar system operates the same as an ordinary solar panel system. However, instead of a single phase solar inverter, you’ll need to incorporate a 3-phase inverter. You’ll still be able to install standard solar photovoltaic (PV) panels as part of a 3-phase solar system – it’s just the inverter type that changes.
Do I need a 3-phase solar system?
Whether you should install a 3-phase solar system will depend on your property’s power supply. If you have a single-phase power supply, you will need to install a single-phase solar inverter and system. This is because a single-phase power connection cannot absorb and transmit power from three different supply points.
If you have a 3-phase power supply, you can install either single or 3-phase solar. Typically, 3-phase power supply is separated across three mains, which means that certain appliances will only be powered by certain wires. However, you have the option to install a single-phase inverter on just one power supply so the appliances on that connection run on solar. Excess solar from this supply can still be diverted to the other two connections through the use of a bi-directional meter (which is generally installed with your solar), before being sent to the grid in exchange for a solar feed-in tariff (FiT).
Be aware that installing a single-phase solar inverter on a 3-phase power supply could impact the voltage on your system. This is due to single-phase inverters having a lower capacity than 3-phase connections, meaning it has to work much harder to transmit the solar power to be used. As a result, a single-phase inverter may trip more frequently than it would if it were 3-phase.
Solar energy plans and prices
Here are some solar-specific energy deals available in New South Wales, Victoria, Queensland and South Australia. These are plans that are marketed towards customers with solar panels and typically offer a higher feed-in tariff than standard market offers. Be sure to read the fine print and double check the base rates on these offers before making a purchase decision.
Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on the Ausgrid network in Sydney but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 3911kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information.
Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on the Citipower network in Melbourne but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 4000kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information.
Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on the Energex network in Brisbane but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 4613kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information.
Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on SA Power network in Adelaide but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 4011kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information.
Single-phase solar power vs 3-phase solar power
Both 3-phase and single-phase solar inverters and systems have their advantages and disadvantages. Here’s a quick look at the pros of each type.
| Single-phase solar | 3-phase solar |
|---|---|
| Significantly cheaper | Reduces issues with voltage rise |
| Can be used with both single-phase and 3-phase power supplies | Higher system capacity and efficiency |
If you operate appliances that have a high-power consumption rate, you may find it worthwhile to install a 3-phase solar inverter and system, as it can generally pull more power in and handle bigger loads.
If you are looking to avoid a higher price tag, you may prefer to install a single-phase solar system.
How much does it cost to install a 3-phase solar system?
The price of a 3-phase solar system will vary depending on a number of factors such as system size, roofing space and the products chosen. According to SolarChoice, you can expect a 3-phase solar inverter to cost you around $500 more than a standard single-phase one.
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3-phase solar inverter brands
There are a number of manufacturers that make 3-phase solar inverters, including:
- Fronius
- SMA
- SolarEdge
- SunGrow
- Huawei
- Growatt
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