The Quick Answer: Circuit Breaker Sizing for EV Chargers in Australia
Wondering what size circuit breaker for EV charger installations you actually need? For most Australian homes using a Level 2 AC charger (7kW), a 32-amp dedicated circuit breaker is the standard requirement. Homes with higher-output chargers (up to 22kW) may need a 40-amp or larger breaker, always installed by a licensed electrician under Australian wiring rules.
Why Circuit Breaker Sizing Matters for EV Charging
Getting the breaker size right isn’t just a technical formality — it directly affects safety, charging speed, and the longevity of your home’s electrical system. An undersized breaker will trip repeatedly during charging sessions, while an oversized one can fail to protect your wiring from dangerous overloads.
EV chargers draw sustained, high loads for hours at a time. Unlike a kettle that runs for two minutes, your charger might pull near its maximum current for six to eight hours overnight. That kind of continuous load demands careful circuit design, not guesswork.
Understanding Australian EV Charger Types and Their Electrical Demands
Before you can determine what size circuit breaker for an EV charger you need, you have to understand which type of charger you’re installing. There are two main categories relevant to Melbourne homeowners in 2026:
- Mode 2 (Portable/Granny Charger): Plugs into a standard 10-amp or 15-amp GPO. Slow charging (1.4–2.4kW). Usually no dedicated circuit required, though a dedicated outlet is strongly recommended.
- Mode 3 (Dedicated Wall Charger / EVSE): Hardwired or plugged into a dedicated circuit. Typically 7kW (single-phase) or up to 22kW (three-phase). This is the setup most Melbourne homeowners are installing.
The vast majority of residential EV charger installations in Australia use a single-phase 7kW unit, which draws approximately 32 amps at 230V. That figure is your starting point for breaker selection.
What Size Circuit Breaker for EV Charger Installations: The Numbers Explained
Australian wiring rules (AS/NZS 3000, commonly known as the Wiring Rules) require that a circuit breaker be rated to handle the continuous load of the connected equipment, with a standard derating factor applied for sustained loads. Here’s how the typical sizing breaks down:
- 7kW single-phase charger: Draws ~32A continuously — requires a 32-amp Type B or Type C circuit breaker on a dedicated circuit with 6mm² cable.
- 11kW three-phase charger: Draws ~16A per phase — requires a 3-pole 20-amp circuit breaker with appropriate three-phase wiring.
- 22kW three-phase charger: Draws ~32A per phase — requires a 3-pole 32-amp circuit breaker, typically only suited to homes already on three-phase supply.
It’s also worth noting that many EV charger manufacturers specify a minimum breaker rating in their installation manuals. Always cross-reference the charger’s documentation with your electrician’s assessment — manufacturer specs and AS/NZS 3000 both apply.
Does Your Melbourne Home’s Switchboard Need an Upgrade?
Many older Melbourne homes — particularly those built before the 1990s — still have ceramic fuse boards or older switchboards that can’t safely accommodate a new dedicated EV charging circuit. If your switchboard is full, outdated, or lacks residual current devices (RCDs), an upgrade will likely be required before installation.
A switchboard upgrade isn’t just a compliance exercise. It’s an opportunity to future-proof your home’s electrical infrastructure as energy demands increase. Adding solar, a battery system, or additional high-load appliances like ducted air conditioning all place greater demands on your switchboard — so upgrading now makes good long-term sense.
You can explore more about managing high-load electrical systems in your home on the Goldworks Electrical blog, where we cover a range of topics relevant to Melbourne homeowners.
Single-Phase vs Three-Phase Supply: What’s in Your Street?
Whether you have single-phase or three-phase power supplied to your property determines which chargers are available to you. Most Melbourne residential properties have single-phase supply (230V), which limits you to a maximum of 7kW charging without a supply upgrade.
Three-phase supply (400V) is more common in newer estates, properties on corner blocks, or homes that have previously requested an upgrade from their distribution network service provider (DNSP). If you’re unsure what supply you have, your licensed electrician can check your meter box and confirm with your DNSP.
Upgrading from single-phase to three-phase is possible but involves your network operator and can take several weeks to arrange. It’s worth investigating early if you’re purchasing a vehicle that supports faster three-phase charging.
Safety Standards and Compliance in Australia
All EV charger installations in Australia must comply with AS/NZS 3000 (Wiring Rules) and, where applicable, AS/NZS 3001.1 for electrical installations in caravans and similar. In Victoria, licensed electricians must also comply with Energy Safe Victoria requirements and obtain the necessary certificates of electrical safety upon completing the work.
Only a licensed electrician is legally permitted to install, alter, or connect a dedicated EV charging circuit in Victoria. This is non-negotiable — unlicensed electrical work is not only dangerous but also invalidates your home insurance and may create serious liability issues.
When to Call a Professional
If you’re planning an EV charger installation, the honest answer is: call a professional from the very beginning. Determining what size circuit breaker for an EV charger you need involves assessing your existing switchboard capacity, cable run distances, load calculations, and compliance with AS/NZS 3000 — all of which require a licensed electrician.
The team at Goldworks Electrical specialises in EV charger installations across Melbourne. Whether you need a straightforward 7kW charger circuit or a full switchboard upgrade to accommodate three-phase charging, Goldworks Electrical can assess your property, recommend the right setup, and complete the work to the highest safety standard. Get in touch today to book your EV charger installation consultation.
Conclusion
Understanding what size circuit breaker for an EV charger you need comes down to your charger’s output, your home’s existing electrical supply, and compliance with Australian wiring rules. For most Melbourne homes, a 32-amp dedicated breaker on a single-phase circuit covers a standard 7kW charger — but your specific situation may require a switchboard upgrade or three-phase supply assessment.
Don’t leave this to chance. EV charger circuits carry sustained high loads and must be installed correctly the first time. Reach out to Goldworks Electrical to get expert advice tailored to your Melbourne home and have your charger installed safely, compliantly, and ready for years of reliable use.
Frequently Asked Questions
Can I use an existing power point to charge my EV at home?
Yes, you can use a standard 10-amp GPO with a Mode 2 portable charger, but it’s very slow — typically adding only 10–15km of range per hour. For practical overnight charging, a dedicated Mode 3 wall charger on its own circuit is strongly recommended. A licensed electrician should inspect the outlet and circuit before regular EV charging use.
Do I need a dedicated circuit for my EV charger in Australia?
Yes. Any hardwired or high-current EV charger (Mode 3) must be installed on a dedicated circuit with its own circuit breaker in your switchboard. Sharing a circuit with other appliances is not compliant with AS/NZS 3000 and creates a genuine overload risk, particularly given the sustained current draw of EV charging.
What type of circuit breaker is best for an EV charger — Type B or Type C?
Most EV charger manufacturers and Australian electricians recommend a Type B RCD/MCB combination (also called a Type B RCCB) for EV charging circuits. This is because EV chargers can produce smooth DC fault currents that standard Type A RCDs cannot detect. Always check your charger’s installation manual and confirm with your electrician which type is specified.
How long does an EV charger installation take in Melbourne?
A straightforward EV charger installation — where the switchboard has spare capacity and the cable run is simple — typically takes three to five hours. If a switchboard upgrade is required or the cable run is complex (e.g., through a double-brick wall or underground to a detached garage), the job may take a full day or require a follow-up visit. Your electrician will provide a clearer timeframe after inspecting your property.
