When building a new home or renovating, you want to be well-informed about energy efficiency. One of the key decisions to make is whether you want a single-phase or three-phase power connection to the electricity grid.
Traditionally most Australian homes have a single-phase connection. But recently, we’ve seen a trend towards new build homes installing a three-phase power supply.
Three-phase power combined with rooftop solar can reduce your household power bills to next-to-nothing.
It also provides you with scope to add energy-intensive appliances and power them for free with your solar electricity.
Getting a three-phase connection at the build stage is cheaper than doing it later. It also gives you greater scope to power your home 24/7 with solar panels and battery storage – and easily add fast charging for an electric vehicle down the track.
On this post we explain:
- What three-phase power is
- How can you tell if you have three-phase power?
- Pros and cons of three-phase power combined with solar
What is three-phase power?
Three-phase power has four wires: three active and one neutral. In contrast, single-phase power has two wires: one active and one neutral.
Because three-phase power has three times more active wires than single-phase power, it effectively triples the power available to your home.
Three-phase connection can supply power at the standard 240V and at 415V for appliances that need greater power like some air conditioners, pool pumps etc.
With a three-phase connection, appliances can be split across each of the three phases.
Three-phase power is common in larger homes and commercial premises. It is increasingly becoming the power supply of choice for solar-savvy households.
How can you tell if you have three-phase power?
To check whether you’ve got single-phase or three-phase power to your home, look at your fuse box. If you have three fuses (black rectangular cartridges) you have three-phase power. If you have one fuse, you have single-phase power.
Other ways to check are:
- Look to see if there is one or three wires from the electrical transformer on your street to your house.
- Call your Distributed Network Service Provider (DNSP). You’ll find their details on your electricity bill. The DNSP is not your electricity retailer, but the company who maintains the poles and wires that carry electricity to your home. They are also the company to call in case of power outages. Call them, quoting your NMI number (your Net Meter Identifier) which is on your electricity bill. They will tell you the type of power connection you have.
Pros and cons of three-phase power combined with solar
Here is a list of the pros and cons of getting three-phase power combined with a rooftop solar system. As you will see, the list of pros heavily outweighs the cons!
| Pros of three-phase power and solar | Cons of three-phase power and solar |
| You can install a much bigger solar panels system, at least 15kW and even up to 30kW depending on where you live and what your DNSP will allow.
| Three-phase power is more expensive to set up than single-phase power supply.
It is not guaranteed that all homes can have a three-phase power supply. Contact your DNSP to find out. Or ask us to help.
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| You can export a lot more solar to the grid and receive a solar feed-in credit for it.
As a rule of thumb, you can export between 3 to 6 times more solar with a three-phase connection compared to single-phase. | To make the most of your three-phase power connection and your solar power system, you will need a three-phase solar inverter.
This is approximately $300-$500 more expensive than a single-phase solar inverter.
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| You can run several power-intensive electrical appliances at the same time without tripping your power supply.
You can power these appliances from your free solar electricity during the daytime.
Add battery storage and you can run your entire home on free solar power, 24/7.
| May be unnecessary if:
· Your electricity usage is small, and you don’t intend to make greater use of electricity in your home at any time in the future.
· You don’t envisage purchasing an electric car in the next 10 or so years.
· You aren’t interested in reducing your reliance on electricity from the grid.
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| Problems with voltage rise (common with single-phase homes) will be largely eliminated.
Voltage rise can cause your solar inverter to trip off and shut down your solar power system.
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| More stable voltage to your home, which will prolong the lifespan of your electrical appliances.
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| Charge your future electric car up to 6 times faster than on single-phase.
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| Increases the feasibility for making your home all-electric. |
Get in touch for advice and a quote
If you’d like advice and help to decide whether three-phase power is going to be worth it for you – get in touch!
We can help with:
- Liaison with your Distributed Network Service Provider (DNSP) to establish whether you can get three-phase power supplied to your property
- Getting costings for a three-phase power connection
- Finding out from your DNSP how much solar you can install with three-phase power.
- Finding out from your DNSP how much surplus solar power you can export with three-phase power.
- Quoting for a suitable size solar panels system to maximise the value from your three-phase power connection, as well as battery storage and fast EV charging if required.
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