The short answer#
Most Australian homes have a single-phase supply. A dedicated 7 kW charger on that supply will recharge most EVs overnight and cover everyday driving comfortably. For most households, that is the end of the decision. If you are still working out what a home charger involves, start with the home EV charging guide.
Three-phase power can support 11 kW or 22 kW chargers, but the benefit depends entirely on the car. If the vehicle's onboard charger is limited to 7 kW, a three-phase charger will not charge it any faster. A supply upgrade is a substantial electrical project, so the car, the driving pattern and the cost all need to line up before it makes sense.
What single-phase and three-phase mean#
A single-phase supply uses one active conductor and a neutral. In Australia, the nominal voltage is 230 V. Most houses and apartments are connected this way.
A three-phase supply uses three active conductors. The voltage between any one phase and neutral is still 230 V, but the voltage between phases is 400 V. That allows more power to be delivered through the same size conductors, or the same power with smaller cables.
The arithmetic is simple enough:
- A 32 A single-phase circuit at 230 V delivers about 7.4 kW.
- A 16 A three-phase circuit at 400 V delivers about 11 kW.
- A 32 A three-phase circuit at 400 V delivers about 22 kW.
Those are the charger's maximum outputs. What the car actually accepts is a separate question.
How the supply changes charging speed#
The table below is a planning guide. Range added per hour varies with vehicle efficiency, temperature, state of charge and the onboard charger.
| Supply | Typical charger power | Indicative range added per hour |
|---|---|---|
| Single-phase, 16 A | 3.7 kW | 20–25 km |
| Single-phase, 32 A | 7.4 kW | 40–50 km |
| Three-phase, 16 A | 11 kW | 60–75 km |
| Three-phase, 32 A | 22 kW | 100–120 km |
For a 7 kW charger, eight hours of charging delivers roughly 56 kWh before losses. That is more energy than most daily commutes use. The case for faster charging is usually a short turnaround, a very long daily drive, a shared vehicle or a second EV — not the average week.
Check the car, not just the charger#
Vehicle specifications usually list AC charging power separately from DC fast charging power. A car might accept 7 kW on AC and 150 kW on a DC public charger. The home charger only affects the AC number.
Many EVs sold in Australia accept 7 kW or 11 kW on AC. Some accept 22 kW; many do not. If the car is limited to 7 kW, a 22 kW charger is an expensive way to deliver the same speed.
There is another subtlety. Some cars that accept 11 kW on three-phase may accept only 7 kW on single-phase, because of how the onboard charger uses the phases. Check the actual specification rather than assuming the number carries across.
What a three-phase upgrade involves#
If the property does not already have three-phase power, getting it can involve:
- an application to the electricity distributor
- a new or upgraded service connection
- new consumer mains and meter arrangements
- switchboard replacement or modification
- new cable routes and protection
- the charger itself
This is not a routine addition. It can cost several thousand dollars, and in some locations the network may not be able to provide the capacity without broader works. Apartments and shared properties add another layer of approval.
Even when three-phase is already present, the charger installation still needs a dedicated circuit, suitable protection and a check that the board can carry the load. The existing supply type is an advantage, not a guarantee.
Load management and the real constraint#
The charger is not the only load in the house. A 7 kW charger draws about 32 A continuously. On a 63 A single-phase supply, that leaves roughly 31 A for everything else. That is often enough, but not always.
Electric cooking, ducted air conditioning, a hot water system, a pool pump or a workshop can push the total over the limit. Older homes may have a 40 A or 50 A supply, which makes the margin tighter again.
There are three common responses:
- Reduce the charger's maximum current. A 7 kW charger can be set to 16 A or another lower limit. Charging is slower but the supply is safer.
- Use dynamic load management. The charger monitors the whole home and reduces charging when other loads are high. This can avoid a supply upgrade.
- Upgrade the supply. This is the expensive option, and it should be justified by a genuine need for speed or capacity rather than a sales pitch.
For two EVs, load sharing between chargers is often more sensible than paying for a bigger supply. The cars can take turns or split the available power overnight.
How to decide#
Work through these questions with the installer:
- What is the car's maximum AC charging power?
- How many kilometres do you drive on a normal day?
- How long is the car parked overnight?
- Is the supply single-phase or three-phase?
- What is the main switch rating, and what else runs at the same time?
- Is there space on the switchboard for a dedicated circuit?
- Would load management avoid an upgrade?
- What would a three-phase upgrade cost, including network work?
- Will a second EV be added in the next few years?
- Are you planning solar or a battery that changes the timing of charging?
If the answer to the first question is 7 kW, the answer to the supply question is usually single-phase. Do not buy a three-phase charger for a car that cannot use it, and do not upgrade the supply for a speed you will rarely need.
Bottom line#
Single-phase 7 kW charging is the sensible default for most Australian homes. Three-phase is useful when the car accepts 11 kW or 22 kW, when two EVs need to share a supply, or when the property already has the capacity. Otherwise, spend the money on a better charger, a proper load-management setup or solar instead of a supply upgrade you will not use.
Straight answers
Questions people ask about this
Is three-phase power better for EV charging?
It can be faster, but only with a vehicle and charger that support 11 kW or 22 kW on AC. For a car limited to 7 kW, three-phase offers no charging speed benefit. It may still help with two chargers or future needs.
How do I know if my house has three-phase power?
Ask a licensed electrician to check the switchboard and meter, or ask your electricity distributor. Do not remove switchboard covers yourself. Your electricity bill or meter configuration may also indicate the supply type.
Can I install a three-phase charger on single-phase power?
No. A three-phase charger needs a three-phase supply. Some models are configurable for single-phase or three-phase, but the installation must match the available supply and the manufacturer's instructions.
Sources and further reading
- Australian Government energy information
- Department of Climate Change, Energy, the Environment and Water
- Australian Energy Regulator
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