With electrical vehicles growing in popularity in Australia – especially major cities like Melbourne – more and more people are considering installing home EV chargers for the best convenience. One of the most common questions asked is whether you need a 3-phase mains upgrade to cope with the power demands and what it might cost to upgrade.
This depends on multiple variables, most especially the capacity of the EV charger’s battery and your home’s existing electrical circuitry. Your charging patterns are another consideration. Many EV chargers can run on a single-phase power supply overnight to give enough charge for the next day. However, 3-phase power offers distinct advantages when it comes to faster and more efficient charging, or when you have a more powerful EV charging unit.
Single-Phase Charging Explained
Most Australian homes use single-phase power. It’s all you usually need for standard appliances and other electricity needs. This is also sufficient for basic home EV chargers that don’t draw more than 7 kW, which is the maximum power output limit of a single-phase system. These smaller chargers will charge overnight at a rate of around 35-40 km of range per charging hour, which is plenty if you’re mostly using your car to commute to work and back.
However, while single-phase power is reliable in this scenario, it imposes a few constraints on EV charging capacity. Larger batteries in EV chargers for MPVs or higher performance cars will be slower to charge, so you might not get a full charge overnight, limiting your driving range. You can also only charge one car at a time with single-phase power, which is a clear problem for households with two breadwinners who both need to charge their vehicles overnight. A 3-phase power installation will make your life a lot easier.
3-Phase EV Charging Benefits
A 3-phase mains upgrade provides more power for EV charging and offers more flexibility. It can deliver up to 22kW. This not only allows you to charge larger units in MPVs and the like; it can also triple the charging speed compared to a single-phase circuit.
You’ll gain:
- Faster charging for larger EV batteries – you won’t have to rely on long overnight charging.
- More stable and efficient power delivery – electrical demand is spread across 3 phases rather than only one, which reduces strain on your electrical circuit.
- Household future-proofing – 3-phase power installation gives your home a robust foundation to support multiple EV chargers and additional appliances safely and reliably, such as induction stovetops and heat pumps.
When to Consider a 3-Phase Mains Upgrade
We’ve noted that not every EV charger needs 3-phase power, but there are scenarios where you should consider converting – and not only to run multiple EV chargers.
If your household already has several power-hungry major appliances and equipment like induction cooktops, ducted air conditioning, pool heaters or a Jacuzzi, you’ll need a 3-phase power installation to use EV chargers at the same time. A more capable electrical system can handle such high loads safely without voltage loss.
Larger vehicles have higher capacity batteries requiring more powerful charging input. A 3-phase system will ensure that you can fully charge them much faster. And of course, businesses with EV fleets will gain efficiency and save valuable road time by being able to charge multiple vehicles at once.
Costs and Practicalities
In general you can expect a 3-phase power installation in Melbourne to cost between around $2,500 to $6,000. This wide disparity is down to several factors:
- How far your switchboard is from your DNSP street point, and whether trenching or boring is required to lay cabling to it.
- The existing capacity and condition of your wiring system.
- The type of switchboard you have – outdated ones will need to be replaced to handle 3-phase power.
- Whether any installations need to be moved, such as your electricity meter.
Note that the actual EV charger installation has nothing to do with your 3-phase mains upgrade. It’s a separate cost, but it’s much simpler if you already have 3-phase power. Moreover, getting it done sooner will provide electrical future-proofing that’s worth the investment.
3-Phase EV Charging FAQs
Can I install a 22 kW charger on single-phase?
No, a single-phase electricity supply can only support up to 7.4 kW. If you want to install a 22 kW charger you’ll need to upgrade to 3-phase power.
Does my car need to support 3-phase to benefit?
Yes, your vehicle needs to have a 3-phase AC charger to accept the 22 kW input. Make sure that yours is compatible before you convert your electrical system, as some models can only use single-phase alternating current.
Can apartments upgrade to 3-phase?
Some modern apartment buildings already have 3-phase power, while older ones may need significant upgrading to install it. Of course this usually requires approval from the body corporate or the building owners.
Is it worth upgrading if I only charge overnight?
If you only have one small EV, single-phase overnight charging could be all you need. However, you won’t be able to run a second EV charger or fully charge a more powerful vehicle if you get one later.
Learn more about our single to three phase mains upgrades in Melbourne and get your home EV-ready today.
