Most NZ homes are single-phase. Adding three-phase supply costs $3,500–7,000, takes weeks, requires the network company's involvement, and is rarely worth it for residential charging. But it's the right call in some situations — here's how to tell which.
§01When three-phase is worth it
- Your house already has three-phase supply (most newer-build homes since 2010).
- You drive an EV that can actually accept 22kW AC — currently a small list, including Renault Zoe and some Audi e-trons. Most Teslas, Leafs, and Polestars cap at 11kW.
- You're a multi-EV household with both cars needing daily fast charging.
- You're already doing a major electrical upgrade (solar + battery + EV in one project).
§03When three-phase isn't worth it
- You drive a single EV with 7–11kW max AC capability.
- Your daily commute is under 80km — overnight 7kW is more than enough.
- Adding three-phase supply requires a transformer upgrade in your street (network company will tell you).
- You're planning to move within 5 years; the install doesn't depreciate well at resale.