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Is your home running on single phase power?
Most Melbourne homes are, and for a long time, that was perfectly fine. But the way we use electricity at home has changed dramatically. EV chargers, ducted reverse-cycle systems, solar inverters, induction cooktops – single phase power wasn’t designed to carry all of that at once.
So how do you know if it’s time to upgrade? Here’s what you need to know.
A Quick Introduction
- Single phase power (230V, one live wire) suits most standard homes with typical appliance loads.
- Three phase power (three live wires) gives you significantly more capacity and a more stable supply.
- You likely need to consider a three phase power upgrade if you’re installing an EV charger, multiple air conditioners, large solar, or running heavy workshop equipment.
- The upgrade involves your electrician, your network distributor (e.g. AusNet, Powercor, CitiPower), and usually a switchboard upgrade.
- Most streets in inner and middle Melbourne already have three phase supply available, it just needs to be connected.
What’s the Difference Between Single Phase and Three Phase Power?
Think of single phase as one lane of traffic. It delivers electricity in a single alternating wave, which works well for everyday loads – lighting, the TV, the dishwasher.
Three phase power is three lanes. Electricity is delivered across three separate wires simultaneously, each carrying the same voltage but staggered in timing. This means the load is spread more evenly, the supply is more stable, and your home can handle significantly more power without overloading a single circuit.
In practical terms: single phase connections in Australia typically max out at around 63 amps, which equates to roughly 14kW of continuous capacity.
But once you start stacking high-draw appliances with things like ducted air conditioning pulling 8kW, a heat pump drawing 3kW, and an EV charger adding another 7kW, you’re pushing up against that limit.
Three phase spreads that demand across three circuits instead of one.
When Do You Actually Need a Three Phase Power Upgrade?
This is the question most Melbourne homeowners are asking. Realistically, you probably don’t need three phase for a standard home with standard appliances. But you should seriously consider it if any of these apply.
You’re installing an EV charger
Most three phase chargers deliver up to 22kW, compared to just 7kW on single phase power. If you want to charge overnight without waiting all day, three phase makes a real difference.
You’re adding multiple air conditioners or a large ducted system
Each unit draws significant power. Running two or three simultaneously on single phase regularly trips circuits. Three phase handles this comfortably.
You’re installing a large solar system
With three phase, power is more evenly distributed, allowing your inverter to operate at peak performance. If you’re going beyond a 5kW system, three phase is often the better foundation.
You’re running a home workshop
Three phase motors are more efficient and better suited to heavier equipment like lathes, compressors, and welders.
You’re building or doing a major renovation
If you’re already pulling the walls apart, it’s the lowest-cost time to upgrade. you’re not paying for access twice.
What Does a Three Phase Power Upgrade Involve?
The process has a couple of steps, but a licensed electrician will manage most of it on your behalf.
- First, your electrician assesses your current setup: the age and capacity of your switchboard, the condition of your mains cabling, and whether your street has three phase supply available (luckily, most streets in inner Melbourne do)/
- From there, an application goes to your network distributor (AusNet, Powercor, CitiPower, or Jemena depending on your suburb). They upgrade the connection at the street, and your electrician handles everything on the property side, including a switchboard upgrade if your current board isn’t up to the job.
It’s also worth checking your mains cabling at this stage. Older Melbourne homes sometimes still have cotton-insulated cable running to the main switch – it’s unsafe and will need replacing regardless.
The whole process typically takes a few weeks from application to completion, with the physical work done in a day or two.
Will Three Phase Power Cost More to Run?
Not necessarily.
Having three phase supply doesn’t increase your bill, as you only pay for what you use. The supply charge may increase slightly depending on your retailer’s tariff structure, but the difference is typically small. And for most homeowners adding solar, that’s quickly offset anyway.
The upfront cost of the upgrade is the main consideration – and that varies depending on your switchboard, mains cabling, and distributor charges.
It’s worth getting a fixed-price quote so you know exactly what you’ll pay.
Need to Upgrade?
If you’re loading up your home with modern, high-draw appliances and noticing tripped breakers or slow charging times, it’s worth a conversation.
Sometimes a power upgrade is the answer rather than a full three phase conversion – it depends entirely on your situation.
O’Shea has been helping Melbourne homeowners work this out for over 40 years. We’ll assess your setup honestly and tell you what you actually need, not just what costs the most.
Call us on (03) 9900 1010 for an obligation-free assessment, or request a quote online. We’re available 7 days a week across Melbourne.