EV Charger Installation in Christchurch: How We Wire Your EV Home Charger
What actually happens between your switchboard and the charger on the wall, why each part is there, and what a proper job costs.
The Sydenham Charger That Shared a Circuit With the Freezer
Last autumn a Sydenham homeowner asked us to look at a charger that kept tripping. It had been fitted by a mate of a mate. The charger was fine. The wiring behind it was not: a 2.5mm cable on a 20A breaker, shared with the garage sockets and a chest freezer, and no RCD anywhere on the circuit. Every evening the car and the freezer fought over one cable, and the breaker kept stepping in before the cable cooked.
We ran a new dedicated circuit, fitted an RCBO for the charger and gave the freezer its socket back. Nothing has tripped since. The point of the story is simple: the charger on the wall is the easy part. The installation is what keeps it safe.
What Goes Into an EV Charger Installation, Part by Part
| Part | What it does | Why it matters |
|---|---|---|
| Dedicated 32A circuit | Feeds the charger and nothing else | A 7kW charger draws close to 32A for hours. Sharing that with sockets is how cables overheat. |
| RCBO at the board | Overload and earth-leakage protection in one device | Trips if current leaks to earth, which is what happens when a person becomes part of the circuit. |
| DC leakage protection | Built into most modern chargers | A car can leak DC current, which an ordinary RCD can miss. We check the charger covers it. |
| Correctly sized cable | Usually 6mm² on a short 32A run, heavier over long distances | Undersized cable runs hot and drops voltage, so the car charges slower. |
| Isolator switch | A local off switch beside the charger | Lets you or a service tech kill the power at the wall without opening the board. |
| CT clamp, where fitted | Measures household current for load management | Lets a 7kW charger share a 63A supply without tripping the mains. |
Cable size depends on the distance and the way the cable is run. We work it out from your photos and confirm it on the day.
Signs of a Good Install
- The charger has its own labelled breaker in the switchboard
- Cable is clipped tidily, in conduit outside, never loose across the floor
- The isolator sits within reach of the charger and is clearly marked
- Your car is plugged in and tested at full rate before anyone leaves
- Your Certificate of Compliance lands in your inbox the same day
Signs It Was Done on the Cheap
- The charger is wired off an existing socket or lighting circuit
- Nothing on the board protects the charger circuit against earth leakage
- Nobody mentions a CoC, or tells you that you do not need one
- The quote is an hourly rate with materials on top
What EV Charger Installation Costs Here
Labour for a standard installation is $873 including GST, with the dedicated circuit, up to 10m of cable and your Certificate of Compliance. Supplied with a 7kW smart charger, most jobs start at $1,422 and land between $1,422 and $2,868. Longer cable runs, trenching to a detached garage or a tired switchboard add to that, and every extra is written on the quote before you agree to it.
The installation cost guide breaks every line down, with three real Canterbury jobs and an estimator.
Book Your EV Charger Installation
Four photos are all we need: your switchboard with the door open, the spot where the charger will go, the path between them and your meter board. One written number comes back, usually the same day.