A three-phase upgrade for EV charging sounds like the obvious way to charge faster. Sometimes it is. Whether it pays off depends on three things, checked in a fixed order: the car, the network and the house.
We are DUKE EV, part of DUKE Electrical Group. Our A-grade electricians handle the whole job under REC 35838, from reading your car’s specifications to lodging the network application, upgrading the switchboard and fitting the charger.
Single-phase and three-phase supply, without the jargon
The Victorian Service and Installation Rules (VSIR) list the standard low-voltage supplies as single-phase 230 volt, three-phase 400/230 volt and a three-wire 460/230 volt system. A single-phase home has one active conductor coming in from the street. A three-phase home has three, each able to carry its own share of the load.
For charging, that is the gap between about 7.4 kW (230 volts at 32 amps on one phase) and about 11 kW or 22 kW (16 or 32 amps on each of three phases). United Energy puts the practical difference this way: a typical 22 kW charger requires three-phase power and charges modern EVs in five to eight hours, while a basic 7 kW home unit takes eight to 12. The 11 kW step deserves a look too, because some cars stop at 11 kW on AC, as the next section shows.
Three phases also spread the big loads. Ducted heating and cooling, an induction cooktop, a pool heat pump and a charger can sit on different phases instead of piling onto one. In a large all-electric house that balance can be the better reason to upgrade, with faster charging as the bonus.
Check the car before you check the pole
The car’s onboard charger caps how much AC power it accepts, and that cap varies by model. Polestar’s Australian specifications for the Polestar 2, for example, list 11 kW AC charging on a three-phase 16 amp supply. Put that car on a 22 kW wall charger and it still charges at 11 kW.
A car with a single-phase onboard charger gets less again. Whatever is on the wall, it charges at its single-phase rate, so for that car a three-phase upgrade does nothing for charging speed at all.
So we start with the specification sheet for your exact model and year, not a forum figure. Two EVs change the sums, though. With three phases, two single-phase chargers can sit on different phases rather than sharing one, which is a fair reason to upgrade even when neither car can use three phases on its own. And if you are about to change cars, check the new model’s AC figure before booking anything; the upgrade only makes sense against the car you will actually be charging.
How a three-phase upgrade for EV charging moves through the network
A supply upgrade involves more parties than most electrical work, and the Victorian Service and Installation Rules give each one a defined job.
| Who | What they do |
|---|---|
| You | Agree the supply you need with your electrician and choose your electricity retailer |
| DUKE EV, your registered electrical contractor | Assesses the site, lodges the application, does the electrical work and issues the Certificate of Electrical Safety |
| Licensed Electrical Inspector | Inspects prescribed work, such as new consumer mains or a main switchboard, before it is connected |
| Your distributor | Assesses the network, sets any conditions and connects the new supply on receipt of the certificate |
| Your retailer and its metering provider | Receive the Electrical Work Request; the metering provider installs the meters and asks the distributor to connect |
Each network has its own front door. CitiPower and Powercor take changes to an existing power supply through their eConnect portal, list “changing your supply setup (such as single or three-phase power)” among them, and say alteration applications “can only be submitted by a qualified registered electrical contractor (REC)”. United Energy takes alteration requests through its myEnergy portal, and AusNet through EnergyConnect. Jemena treats a change from one phase to three as an alteration, unless the point of supply moves, say to a new pole, which makes it a new connection.
Timing is set by the network, not by us. CitiPower says most works take between 3 and 8 weeks, depending on complexity, and can take longer because of missed appointments, unsuccessful field visits or delays with retailer service orders.
The Victorian Service and Installation Rules, in their advice on equipment that may disturb supply, say no expense should be incurred until the distributor has advised whether, and on what terms, supply will be given. We apply that to every supply upgrade: nothing gets ordered until the application comes back.
What drives the cost and the timeline
We won’t put a figure on a three-phase upgrade here, because two houses in the same street can need very different work. These are the things that move it:
- The service cable route. Clause 7.4.4.8.2 of the VSIR covers capacity upgrades, including multiphase supplies. A service cable over a neighbour’s property is only allowed if there is no risk of obstruction and it covers no more than 25% of their front boundary or 2 metres of their side boundary, and service cables can’t run over pools or spas. A route that fails those tests has to change.
- Overhead or underground. An underground service can mean trenching across a garden or driveway, and work on council land needs its own approval. Stonnington requires road and footpath opening consent for connecting new services such as an underground power supply, and the Mornington Peninsula Shire requires an occupation permit to work on a road or footpath.
- New mains and a matching board. Three phases need consumer mains and a main switchboard to match, and both count as prescribed work that an independent inspector checks. That side of the job is covered under upgrading a switchboard for an EV charger.
- Metering. The retailer’s metering provider installs the new meter, which adds a party and an appointment to coordinate.
- Network capacity. Where the network can’t support a change, CitiPower and Powercor run a network upgrade process, and they name high-capacity EV charging installations among the examples. United Energy lists premises needing 170 amps or more among its typical negotiated connections, where the network itself may have to be upgraded or extended.
- The charger and the final run. The charger model and the distance from the new board to the parking spot finish the picture.
Which Melbourne network you are on
Your distributor is set by your address, not by your retailer. CitiPower serves Melbourne’s CBD and inner suburbs, and United Energy the south-east and the Mornington Peninsula. Powercor covers the western suburbs and central and western Victoria, Jemena the northern and south-western suburbs in the VSIR’s description, and AusNet Melbourne’s north and east along with eastern and north-eastern Victoria.
CitiPower and Powercor’s postcode network locator shows which network supplies you. On its data, South Yarra, Toorak, Windsor and the CBD are CitiPower, while Brighton, Beaumaris and Portsea are United Energy. The data works at postcode level, so we confirm the network for your property during the assessment, and our page on EV charger installation in South Yarra covers CitiPower’s inner-city patch.
Network capacity can also follow the calendar. United Energy’s planning report says maximum demand at its Sorrento zone substation, which supplies Blairgowrie, Portsea, Rye and Sorrento, normally occurs over the Christmas and New Year holidays. A Portsea holiday house asking for three phases is asking a network that peaks exactly when the house is full. For the holiday-home side of peninsula charging, read EV charger installation in Portsea.
Solar owners have one more reason to care. United Energy’s 2022 installer FAQ, still linked from its EV page, says systems up to 10 kVA with 5 kVA export on a single-phase site, or 30 kVA with 15 kVA export on a three-phase site, are covered by its model standing offer. Each site is still assessed, and pairing panels with a charger is covered under solar EV charger installation.
Alternatives that often make more sense
Honestly, if charging is the only reason, a three-phase upgrade is hard to justify for most single-car households. Three options usually come first.
A single-phase 7 kW charger
Eight hours overnight at about 7.4 kW delivers roughly 59 kWh before charging losses. Compare that with your battery size and your weekly driving before deciding you need more. Our page on single-phase home EV charger installation covers choosing and placing one.
Load management
If the worry is the house running short of capacity with the charger on, a load-managed charger turns itself down when the rest of the house is busy. It trades a little charging speed at peak times for skipping the supply upgrade and its network application.
Smarter scheduling
Charging in the cheapest hours does more for running costs than charging faster. A smart charger scheduled around time-of-use rates, or around your solar output, needs no extra phases.
We would upgrade when there is a second reason: a second EV, an all-electric renovation, a bigger solar system, or a switchboard that is being replaced anyway.
Frequently asked questions about three-phase upgrades
Will a three-phase supply make my EV charge faster?
Only if the car’s onboard charger accepts three-phase AC, and only up to its own limit. We check the specifications for your model before recommending the upgrade.
Can I organise the upgrade with the network myself?
On CitiPower and Powercor’s networks, alteration applications can only be submitted by a registered electrical contractor, and the electrician arranges the appointments. We lodge the application and coordinate the inspector, the retailer and the metering provider for you.
Will I need a new meter?
Expect one. In the VSIR’s connection process, the retailer’s metering provider installs the meters for the new supply and then asks the distributor to connect.
Do I need three-phase power for a 22 kW charger?
Yes. CitiPower and United Energy both say a 22 kW charger needs three-phase power. With single-phase power, about 7 kW is the usual ceiling for a home wall charger.
What happens if the network can’t support three phases at my address?
Then the network has to do its own work first. CitiPower and Powercor, for example, apply a network upgrade process, and we wait for the distributor’s answer before anything is ordered.
Have your car’s make, model and year handy, and a photo of your meter box if you can, and we can say whether three phases would change anything for you. Talk to us about a three-phase upgrade through our contact page, or ring 1300 003 853 between 7am and 7pm, Monday to Saturday.