Most Adelaide homes run on single phase, which is fine for everyday use. A three-phase upgrade makes sense when you want solar above about 10 kW of inverter, fast EV charging, large ducted air con or three-phase machinery, or your supply struggles under combined load. SA Power Networks must approve it, and cost depends on your street supply, mains run and switchboard.
- Most Adelaide homes don't need three phase for everyday use.
- Big solar, fast EV charging, ducted air con and machinery are the usual triggers.
- SA Power Networks must approve it and three phase must be available in your street.
- Network and metering steps take longer than the on-site work.
- Check whether a switchboard upgrade or load management solves it first.
Single phase vs three phase: what actually changes
Single phase brings power into your home on one active wire. Three phase brings three, each carrying power out of step with the others. Same voltage at your power points, but roughly three times the capacity overall.
- More capacity. Big loads can be spread across three phases instead of piling onto one.
- Smoother running. Motors, pumps and larger inverters run more evenly on three phase.
- Bigger solar. SA Power Networks usually limits single-phase homes to around 10 kW of inverter. Three-phase homes can usually connect more, within SA Power Networks' limits.
It doesn't make each kWh cheaper. It just lets you run more at once.
Do I need three-phase power? Six signs
- Your solar or battery quote needs more than single phase allows. Common once you want a large array or a big battery inverter.
- You want a fast EV charger. Standard home chargers run fine on single phase. Faster ones may need three phase, if your car can use it.
- Breakers trip when several big appliances run together. Air con, oven, hot water and a charger at once can be too much for one phase.
- Lights dim when motors start. Pool pumps, compressors or air con kicking in shouldn't dim the house.
- You've bought equipment that's three-phase only. Workshop machinery, some heat pumps and commercial kit.
- A business has changed what it does. New ovens, cool rooms or machines added after the supply was set up.
Tell us what you're planning to add. We'll check your supply and tell you straight whether you need three phase.
Which Adelaide properties most often need it
Homes going all-electric at once
Solar, a battery, an EV charger, ducted air con and a heat pump hot water system can add up fast. Planning it as one job is cheaper than upgrading in pieces. Our Hayborough install, 18.3 kW of solar with a 35 kWh battery, is one of our three-phase systems.
Rural and hobby-farm properties
Bore pumps, sheds and workshops are typical three-phase loads.
Businesses whose equipment outgrew the supply
Shops, cafes and workshops often add equipment over years without anyone checking the supply. See our commercial electrical services.
How a three-phase upgrade works
| Step | What happens |
|---|---|
| 1. Load assessment | We look at what you run now and plan to add, and check whether three phase is actually the answer. |
| 2. Network application | We apply to SA Power Networks. Three phase has to be available in your street. |
| 3. Switchboard and mains | Usually a new or upgraded switchboard and new mains cable from the street connection. |
| 4. Metering | The meter is changed to suit three phase, arranged through your retailer. |
| 5. Balance and test | Circuits are spread across the phases, tested and signed off. |
The on-site electrical work is usually the quick part. The network and metering steps are what take the longest, so it pays to start early if you have a solar or battery install planned.
Three phase, solar and batteries
Solar is the most common reason Adelaide homes ask us about three phase. On single phase, SA Power Networks usually caps you at around 10 kW of inverter. If your roof and usage suit a bigger system, three phase can let you install more.
It's not automatic, though. Three-phase homes still have export limits set by SA Power Networks, and a bigger system only pays off if you can use or store the power. We'll show you the numbers both ways on your quote. If you're already three phase, make sure your inverter and battery are designed for it, so loads and solar are balanced properly. See our solar battery page for how we size storage.
What drives the cost of a three-phase upgrade
There's no standard price because the biggest cost drivers are outside your house. Here's what we look at:
- Whether three phase is already in your street
- Overhead or underground supply, and the distance to your switchboard
- Whether your switchboard can be upgraded or needs replacing
- How many circuits need moving or rebalancing
- Trenching, boring or wall chasing for the new mains
- Network and metering charges
We'll come out, check the site and give you a free, itemised quote that shows each part.
Is three phase always the right answer?
No. We'd rather tell you that up front than sell you an upgrade you don't need.
- A switchboard upgrade may be enough. Old fuses and a full board are often the real problem.
- Load management. Smart EV chargers and load controllers like Catch Power can stop big loads running at the same time.
- Single-phase equipment. Many heat pumps, chargers and battery inverters come in single-phase versions.
If you're planning solar, a battery or an EV charger, ask us to check your supply as part of the quote. Our three-phase upgrade service page has more detail.