Free Tool  |  AS/NZS 3000 & BS 7671  |  No Signup

EV Charger
Load Calculator

Can your electrical panel handle an EV charger? Enter your panel details, proposed charger, and existing loads to find out — with recommended breaker, cable size, and RCD protection.

Free. Works on mobile. Standards-compliant.

40A
Typical breaker for 7.4kW charger
6.0 mm²
Typical cable for 7.4kW charger
<80%
Recommended panel utilisation

Check Your Panel

Enter your existing panel details and proposed EV charger to see if your panel can handle it.

Existing Electrical Panel

Check your main switch rating

EV Charger & Existing Loads

Home chargers: 7.4kW is most common

Sum of all existing circuits on the panel

From main switchboard to charger location

How It Works

Panel Utilisation Check

See exactly how much of your panel capacity the EV charger will use.

Breaker & Cable Sizing

Get recommended breaker size and cable size based on your charger rating.

RCD Protection

Correct RCD type for EV charger installations per AS/NZS 3000.

All Charger Types

Supports 3.6kW, 7.4kW, 11kW, and 22kW chargers on single and three phase.

Why Use This Calculator

Free — no signup required
AS/NZS 3000 and BS 7671 compliant calculations
Instant results as you change inputs
Shows if panel upgrade is needed before installation
Recommends exact breaker and cable size
Works on mobile for on-site use

Frequently Asked Questions

Can my panel handle a 7.4kW EV charger?

A 7.4kW charger draws approximately 32 amps on single phase. Most NZ homes have a 63-amp main switch. If your existing loads total less than 30 amps, you can typically add a 7.4kW charger without upgrading the panel.

Do I need three phase for an EV charger?

For chargers up to 7.4kW, single phase (230V) is sufficient. For 11kW or 22kW chargers, you need a three-phase supply (400V). Most residential homes in NZ and AU have single phase.

What size breaker do I need for an EV charger?

The circuit breaker should be rated at 125% of the charger continuous load. A 7.4kW charger (32A) typically needs a 40A breaker. A 3.6kW charger (15A) needs a 20A breaker.

What cable size for a 7kW EV charger?

For a 7.4kW charger on a 40A breaker, a 6.0 mm\u00B2 copper cable is typically suitable for runs up to 25 metres. For longer runs, 10.0 mm\u00B2 may be required to stay within voltage drop limits.

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