HomeSingle Phase vs Three Phase
Power Supply Comparison

Single vs Three Phase Power: Do You Actually Need the Upgrade?

EV chargers, ducted air con, induction cooking and heat pumps are pushing Sydney homes to the limit of single-phase supply. When three-phase is genuinely necessary, what it costs in 2026, and when you can skip it.

Quick Answer

Most Sydney homes are fine on single phase. You genuinely need three-phase for a 22kW EV charger, ducted air conditioning above roughly 14kW, serious workshop machinery, or when your combined peak load (EV + heat pump + induction + AC) exceeds the single-phase supply. A single-to-three-phase conversion costs $6,500–$9,500 fully installed in 2026 — or $9,500–$14,000 if the network needs augmenting — plus $1,800–$3,500 for the three-phase switchboard it almost always requires. This is Level 2 ASP work end to end, and we handle the network application, metering and certification as one job.

Comparison

Side by Side

FactorSingle PhaseThree Phase
What it isOne active conductor — standard for most homesThree actives — triple the deliverable power
EV charging7kW max — overnight charging, fine for most drivers22kW — full charge in a few hours
Ducted ACUp to ~14kW coolingRequired above that — large homes, two-storey ducted
Workshop / machineryDomestic tools onlyWelders, compressors, lifts, commercial kitchen gear
Conversion cost$6,500–$9,500 (+$1,800–$3,500 switchboard)
Who can do itLevel 2 ASP only — new service line, metering, POA and network notification
When It's Worth It

When Three Phase Is the Right Call

1

22kW EV charging. It will never run on single phase — if fast home charging matters to you, three-phase is mandatory, not optional.

2

Whole-home electrification. Stacking an EV, heat pump hot water, induction cooktop and big AC on one phase means load-shedding your own house on a summer evening.

3

Building or renovating anyway. If walls are open and the switchboard's being touched, adding three-phase now is far cheaper than retrofitting in five years.

4

Granny flats and dual occupancy. Separate metering and higher combined load often make three-phase the sensible supply for the site.

Honest Advice

When You Can Skip It

Single phase is completely adequate for most homes

A 7kW single-phase EV charger fully recharges most cars overnight. If you're not running oversized ducted AC or machinery, and you're not electrifying everything at once, single phase with a decent switchboard upgrade is thousands cheaper and completely adequate. We'll tell you straight which camp you're in — see our three-phase upgrade service and the 2026 cost guide.

Common Questions

FAQs

How do I know if my house already has three phase?

Look at the main switch in your board — a wide switch spanning three poles usually means three-phase, a single-pole switch means single. Three separate actives at the service pit or attachment is the other giveaway. We confirm it in seconds during a quote.

How long does a three-phase conversion take?

The on-site work is typically a day once the network disconnection is scheduled. The lead time is in coordination — metering, distributor notification and, if needed, network augmentation.

Can a regular electrician install three-phase power?

No. The new service line, metering, point of attachment work and network notification are Level 2 ASP territory. A standard electrician can wire three-phase circuits inside the house once the supply exists. See Level 2 vs standard electrician.

Get a Straight Answer and a Fixed Quote

Tell us what you're planning to run — we'll confirm whether you need three-phase, and quote the conversion end to end.

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