Home EV charger electrical plan: prepare a clear installation

Why prepare the plan before choosing the charger?

The power printed on a charger is only one part of the design. The vehicle, parking time, electricity plan, existing switchboard and distance to the parking space all affect the final solution.

An electrical plan brings these decisions together. It shows the actual parking position, the side of the vehicle charging port, the possible cable route and the equipment needed near the switchboard.

• Location of the wallbox or dedicated EV socket-outlet.
• Distance and route between the switchboard and parking space.
• Indoor, wall, garage or underground conduit route.
• Possible location of load management and sub-metering equipment.

Dedicated socket-outlet or wallbox: what should the plan show?

A dedicated socket-outlet (Mode 2 charging, with the cable supplied with the car) can suit low daily mileage when the vehicle stays parked for a long time. A wallbox (Mode 3) usually offers more power, finer load control and scheduling or monitoring features. In New Zealand, socket-outlets must not be installed for Mode 1 charging (clause 7.9.3.1).

Common comparison points include up to 3.7 kW for slower charging, 7.4 kW on single phase, and 11 or 22 kW when both the vehicle and a three-phase installation support it. The actual rating must be validated against the property and the vehicle.

• Daily driving range to recover.
• Usual parking duration at home.
• Maximum AC power accepted by the vehicle.
• Available supply and load-management options.

3.7, 7.4, 11 or 22 kW: which power should you install?

Charger power is measured in kilowatts (kW), while kilowatt-hours (kWh) measure battery capacity. The power actually received by the car is always limited by the weakest link: charger, vehicle onboard charger, supply capacity or the property installation.

The most powerful wallbox is therefore not automatically the best choice. When a car stays parked overnight, 3.7 or 7.4 kW may be enough; 11 or 22 kW is mainly relevant with a three-phase supply, a compatible vehicle and a need for faster charging.

• 3.7 kW — single phase, roughly 16 A: slow, but enough for a short commute and a car parked all night.
• 7.4 kW — single phase, roughly 32 A: the usual home wallbox, and what most home installations end up being.
• 11 kW — three phase, roughly 16 A per phase: only relevant if the property has a three-phase supply.
• 22 kW — three phase, roughly 32 A per phase: needs three phase, a compatible car and the supply capacity to match. Many vehicles cap AC charging at 7.4 or 11 kW anyway.

What should appear on the electrical plan?

The plan should be detailed enough to prepare a quote without pretending to replace the electrician’s technical study. Show the charger, its dedicated route to the switchboard and the visible constraints along that route.

In Planelico, you can distinguish a wall-mounted charger, pedestal charger, dedicated socket-outlet or future provision. Dedicated symbols also cover dynamic load management, sub-metering, emergency isolation and an outdoor conduit.

After placing a wallbox, select it in the editor to choose 3.7, 7.4, 11 or 22 kW. “Generate circuits & panel” then creates the dedicated circuit, sizes a single-phase wallbox at 32 A at least, puts it behind a Type B RCD and adds the isolating switch to the quote.

• Charger, dedicated socket-outlet or provision for future work.
• Dedicated circuit kept separate from general power circuits.
• Dynamic load manager linked to the meter or switchboard.
• Conduit, penetrations and approximate route length.
• Notes about access, weather exposure and future extensions.

AS/NZS 3000 clause 7.9 and what it means for the circuit

In New Zealand, clause 7.9 of AS/NZS 3000 sets mandatory rules for EV charging. The supply must be TN-C-S (MEN), and the charger must not be supplied from a switchboard fed by a PEN conductor under the outbuilding provisions (clause 7.9.2). The charging facility sits next to the parking area.

For a home, every charging circuit is dedicated and protected by a 30 mA Type B RCD that switches both active and neutral; an RCBO may be used. A Mode 2 socket-outlet needs a circuit of at least 20 A; a single-phase Mode 3 wallbox needs a circuit of at least 32 A, a direct connection and an isolating switch of at least 32 A. The socket-outlet or charging cable outlet sits at least 800 mm above the floor or ground (clause 7.9.3).

WorkSafe’s EV charging safety guidelines and their addenda add detail — for example on accepted alternatives to a Type B RCD. Your electrician applies the current version.

• A dedicated circuit, at least 32 A for a single-phase wallbox.
• 30 mA Type B RCD switching active and neutral (RCBO allowed).
• Isolating switch of at least 32 A for a wallbox.
• Charging outlet at least 800 mm above the floor or ground.

Plan smart charging before increasing the supply

Dynamic load management adapts charging to the home’s live demand. It can temporarily reduce the charger when cooking, hot water or air-conditioning loads are high and increase it again when capacity becomes available.

Many chargers schedule charging for off-peak tariffs or solar surplus. Show the intended control link on the plan, not just the power cable: a current transformer on the incoming supply is common and needs a route of its own.

Incentives: check the current scheme, not an old article

Support for home chargers in New Zealand has changed over time and depends on current government and power-company programmes. Eligibility and amounts change.

Check the current schemes at the point you accept a quote, rather than relying on a figure quoted in an older article or by an installer.

What the plan does not replace

The plan prepares the location, route and desired equipment. On its own it does not calculate voltage drop, final cable size under AS/NZS 3008, protective devices, earthing, maximum demand or the suitability of the existing switchboard.

Give the PDF to a licensed electrician so they can inspect the property, size the circuit and confirm the usable charging power before work starts.

Quick method with Planelico

1. 1

   Import the property plan

   Add the PDF for the home, garage and any relevant outdoor area.

2. 2

   Place the charger

   Position the wallbox, pedestal, dedicated socket-outlet or future provision beside the parking space.

3. 3

   Locate the switchboard

   Mark the board that will supply the dedicated circuit, and note whether it has a spare way.

4. 4

   Draw the proposed route

   Show the cable route, penetrations and any outdoor conduit.

5. 5

   Add smart controls

   Mark load management, the current transformer on the incoming supply and any sub-metering.

6. 6

   Export for quotation

   Generate a readable PDF for pricing and validation by a licensed electrician.

Frequently asked questions

Official sources

• Standards Australia — AS/NZS 3000 Wiring Rules
• WorkSafe New Zealand — Electric vehicle charging safety guidelines
• WorkSafe New Zealand — low voltage electrical installations