Single Phase or 3 Phase Power: Which Does Your Sydney Home Need?

What This Article Covers

A quick overview before you dive in:

• How single phase and three phase power differ, and why one supply is enough for most Sydney homes.
• The situations where three phase is usually worth considering, such as a 22 kW EV charger, large ducted air conditioning, a heated pool or spa or workshop machinery, and why what runs at the same time matters most.
• When a single phase switchboard upgrade is enough, for example to add circuits, safety switches, solar or a 7 kW EV charger, and what that costs.
• What a 3 phase upgrade involves, from the network application and any Level 2 work to the new board, testing and your compliance certificate.
• What a 3 phase upgrade costs ($7,000 to $11,000+ + GST, with network charges separate), what drives the price and how long it takes.
• The questions to ask before you accept advice that your home needs three phase.

Most Sydney homes run on single phase power, and for most of them it's plenty. Three phase power is usually worth considering for large loads such as a 22 kW EV charger, large ducted air conditioning or a heated pool or spa, especially when several of them run at the same time.

If a solar company, an EV charger installer or another electrician has told you to go three phase, this guide explains what that means, when it's worth it and what it costs, so you can ask the right questions before you commit. The prices in this guide are what Impulse Electrical Enterprise charges in Sydney.

Single Phase and Three Phase Power: The Difference

Single phase power reaches your home through one supply. That's enough for lighting, power points and everyday appliances, and usually for a 7 kW EV charger too. Three phase power brings in three supplies, so large loads can be spread across them, giving the home much more capacity when big appliances run at the same time. Moving to three phase means a new three phase switchboard and an application to your electricity network (Ausgrid, or Endeavour Energy in its area).

Three phase isn't a safety upgrade. It's about capacity: whether your supply can run everything you want at once.

When Three Phase Power Is Worth Considering

Three phase is usually worth considering if you're planning:

• A 22 kW EV charger.
• Large ducted air conditioning.
• A pool or spa with heating.
• Workshop machinery.
• A large home, or a big renovation that adds a lot of new appliances.

What matters most is what runs at the same time. A home that adds a 7 kW EV charger, solar and ducted air conditioning, but rarely runs them all flat out together, may be fine on single phase. A home running a 22 kW charger, ducted air and a pool heater at the same time is a much stronger case for three phase. We check your expected load when we quote.

Solar is another common reason people are told to go three phase. Three phase can sometimes give more options for a larger solar system, but a single phase export limit doesn't automatically mean you need it, and upgrading doesn't guarantee a higher approved export limit. Export limits and connection requirements are set by your network, so we look at your solar system, inverter and current supply before recommending an upgrade.

When a Single Phase Switchboard Upgrade Is Enough

If you mainly need more circuits and safety switches (RCDs), or room for solar, a battery or a 7 kW EV charger, a single phase switchboard upgrade may be all you need. Single phase upgrades start from $1,200 + GST, and a larger board with room for solar, a battery or an EV charger typically costs $4,000 to $7,000+ + GST. These prices assume suitable existing wiring and reasonable access to the board. Extra equipment, new circuits and other work are quoted separately, and your final price is confirmed in a free, fixed quote.

If lights dim when a big appliance starts, the cause may be an overloaded circuit, undersized wiring or a loose connection rather than the supply itself. A safety switch that keeps tripping has usually found a fault, typically a faulty appliance or a problem with the wiring, so get it checked rather than assuming you need more supply. Our switchboard upgrade cost guide explains each price range in more detail.

What Going Three Phase Involves

1. Assessment and quote. We look at your meter, your switchboard and the appliances you want to run together, and give you a fixed price before you book.
2. Network application. The change to three phase needs approval from your network, Ausgrid or Endeavour Energy. We arrange the application and any Level 2 work on the network side, so you only deal with us. Level 2 work is done by an Accredited Service Provider (Level 2), who installs, repairs or maintains the service lines between your home and the network.
3. New switchboard. A new three phase board goes in, with safety switches and every circuit labelled, and the meter to board cable is upgraded if it needs to be. Expect about two days of work on site. The network's approval sets the overall timeframe, which we give you with your quote.
4. Testing and certificate. We test everything before the power goes back on, and you receive a Certificate of Compliance for Electrical Work (CCEW). NSW electricians submit these through the BCNSW eCert portal, and a copy is sent to you.

How Much a 3 Phase Upgrade Costs in Sydney

Most 3 phase upgrades cost $7,000 to $11,000+ + GST. Prices assume reasonable access to your switchboard and meter. Depending on the job, the price may include the Level 2 work on the network side, and your quote shows exactly what's included. Any network charges are separate, and your final price is confirmed in a free, fixed quote before we start.

Three things move the price: the distance from the street connection to your meter and board, whether the board has to move, and how big the new board needs to be. The work needed on the network side also varies from street to street. Our 3 phase switchboard upgrade service has more detail and recent jobs.

Questions to Ask Before You Go Three Phase

• If it's for an EV charger, can my car actually charge at more than 7 kW on AC?
• What will I run at the same time, and does that really exceed my single phase supply?
• Would a single phase switchboard upgrade solve the problem for less?
• Does the quote include the network application, any Level 2 work, the new board, the meter to board cabling and the CCEW?
• Which network charges are separate, and what timeframe should I expect?

If you've been told you need three phase without a clear reason, ask for one before any work is quoted.

Questions About Three Phase Power for Sydney Homes

Do I need 3 phase power for an EV charger?

It depends on the charger and your car. Single phase home chargers usually top out at around 7 kW, which suits most drivers charging overnight. An 11 kW or 22 kW charger needs three phase power, and many EVs charge at up to 11 kW on AC, so check what your car can use before paying for 22 kW. Our EV charger installation service can help you choose the right charger for your home.

Is three phase power safer than single phase?

No. Three phase is about capacity, not safety. Safety comes from a modern switchboard with safety switches (RCDs) protecting your circuits, which a single phase upgrade gives you too.

Can any house be upgraded to three phase?

Most can. Whether yours can depends on the supply in your street, which is checked as part of the network application, and if there's a problem we tell you early.

Not Sure Whether You Need Three Phase?

Tell us what you want to run at the same time, such as a 22 kW EV charger and ducted air conditioning, and we'll tell you whether your home needs three phase or whether a single phase upgrade will do. Call 0481 228 836 or request a free quote. Our phones are answered 24/7, and we're based in Strathfield, working across the Inner West and greater Sydney.