Single-Phase Power

What single-phase means

The electricity delivered to most Australian homes uses a single active conductor - one wire carrying alternating current at 230V (nominal), returning through a neutral wire. This is single-phase power.

The maximum current a standard residential circuit can carry is determined by the service fuse and the wiring. Most Australian homes have a 63A or 80A service fuse at the main switchboard, with individual circuits protected by 10A or 20A breakers. A dedicated EV charging circuit on a 32A breaker is the maximum for most residential single-phase installations.

The 7.4 kW ceiling

Power (watts) = Voltage × Current. At 230V on a 32A circuit, the maximum continuous draw is around 7.36 kW - which is why 7.4 kW is the standard figure quoted for single-phase home EV chargers. A wallbox installed on a dedicated 32A circuit and connected to a car with a 7.4 kW OBC will charge at this rate continuously until the battery reaches the charge limit.

This is genuinely sufficient for the overwhelming majority of EV owners in Australia. Charging at 7.4 kW for 8 hours adds around 400 km of range - more than most people drive in a week.

How to check your supply

Most houses built in Australia have single-phase supply. Signs of single-phase:

• One service fuse at the main switchboard (rather than three)
• The meter shows one active terminal
• No heavy industrial or agricultural equipment on the property

Three-phase supply is most common in new developments, homes with large ducted air conditioning or workshop equipment, and rural properties with heavy machinery. Ask your electrician if you’re unsure - they can confirm from the meter or switchboard in a few minutes.

Upgrading

Having a three-phase supply connected to a single-phase home is possible but involves a fee from your network distributor and potentially significant cabling work from the street. Most EV owners on single-phase power don’t need to bother - 7.4 kW home charging is sufficient. The only scenario where upgrading makes sense is if you’re installing a large commercial-grade charger (11+ kW) or if you already have a separate three-phase supply for other reasons.