- Single phase ceiling
- 7.4 kW 32 A, the standard NZ home charger
- Three phase
- 11–22 kW Only if the car accepts it
- New three-phase supply
- Lines company job Weeks, and quoted separately
This is where people spend money they didn't need to spend. A 22kW charger is a genuinely better product than a 7.4kW one, and for the large majority of New Zealand homes it will charge your car at exactly the same speed. Here's how to work out which side of that line you're on before you buy anything.
How do I tell if my house is single or three phase?
Look at the main switch at the top of your switchboard. A single-phase supply has one main switch, typically a single or double-width breaker with one incoming cable. A three-phase supply usually has a wider main switch spanning three poles, ganged together so they trip as one, and you'll often see three separate incoming conductors. Some boards are labelled outright. If it isn't obvious, a photo of the board with the door open plus one of the meter box will settle it, and that's exactly what we ask for.
What difference does it make to charging?
| Supply | Practical charger size | Roughly, overnight |
|---|---|---|
| Single phase | 7.4 kW (32 A) | A full night's charge covers far more than the average daily drive |
| Three phase | 11 kW or 22 kW | Faster, but only if the car's onboard AC charger can take it |
| 3-pin plug (no charger) | About 2 kW | EECA rates a smart charger at about three times the speed |
3-pin comparison from EECA.
Will my car even use 22kW?
Check the car's maximum AC charging rate on the maker's specification sheet, not the DC fast-charging figure that gets advertised. The onboard AC charger is a component inside the car, and it sets a hard ceiling: if the car accepts 7kW of AC, a 22kW wall charger delivers 7kW. Many popular electric cars and nearly all plug-in hybrids sold in New Zealand sit at or below 11kW on AC. We won't quote per-model numbers here until we've read each maker's New Zealand spec sheet, because that's exactly the sort of detail that goes stale and misleads people.
When is three phase actually worth it?
- You already have three phase. Then the extra cost is just the charger, and there's little reason not to, if the car can use it
- Your car accepts 11kW or 22kW on AC and you regularly need a big top-up in a short window rather than overnight
- Two EVs sharing one charger, where load management splits the available power between them
- You're already upgrading the supply for something else, so the lines-company work is happening anyway
What's involved in getting a new three-phase supply?
It stops being an electrician job and becomes a lines-company job. Your electricity distribution business, Vector in Auckland, Wellington Electricity in Wellington, WEL Networks in the Waikato, Powerco in the Bay of Plenty, Orion in Christchurch, Aurora in Dunedin, has to approve and often physically change the connection. Their fees and lead times are theirs, they vary by network and by street, and they are measured in weeks. We never fold that into a fixed price, because we can't control it. If your photos suggest you'd need it, we say so and price the rest separately.
So what should most people buy?
A 7.4kW single-phase charger, on the supply the house already has. It fits nearly every New Zealand home, it's the cheapest install by a distance, and overnight it puts back far more range than the average daily drive. Spend the difference on a longer cable or better connectivity if you need it, not on power your car can't accept. See the charger packages.
Frequently asked questions
How do I know if I have three phase at home?
Look at the main switch at the top of your switchboard: three ganged poles and three incoming conductors mean three phase, one means single phase. If it isn't clear, send a photo of the board with the door open and of the meter box.
Is a 22kW charger better than a 7.4kW one?
Only if your home has three phase and your car's onboard AC charger accepts more than 7kW. Otherwise it charges at exactly the same speed and costs more to buy and install.
Can I get a 22kW charger on single phase?
No. Single phase caps you at 7.4kW. Getting to 22kW means a new three-phase supply, which is a lines-company job quoted separately.
How much does it cost to go to three phase?
We don't publish a figure, because it depends on your lines company, your street and your existing connection, and we haven't found a source that supports a national range. It's approved and priced by the distribution business, and it takes weeks.
Is 7.4kW enough for a family with one EV?
For nearly everyone, yes. An overnight charge at 7.4kW adds far more range than the average New Zealand daily drive, and a smart charger schedules it into the off-peak window automatically.
What about 11kW?
11kW needs three phase too. It's the sweet spot for cars with an 11kW onboard charger, and it's a smaller step up in cost than 22kW. If you have three phase, tell us the car and we'll say which makes sense.