What is three phase power and do I need it?

Single phase supply is one active conductor and a neutral, and it is what the large majority of Australian homes have. Three phase brings three actives, which raises the total power the property can draw and lets individual circuits be spread across the phases so no single one is loaded to its limit.

How to tell what you have

Open the meter box and look at the main switch. A single, narrow main switch is single phase. A wide main switch spanning three poles, or three separate fuses feeding the board, indicates three phase. If there is any doubt, an electrician can tell you in a minute and it is worth knowing before you plan anything else.

When an upgrade is worth considering

• Ducted air conditioning sized for a large house, particularly combined with a pool pump and an EV charger.
• A workshop with equipment that is only made in a three phase version, such as a large welder or a kiln.
• Faster EV charging, since single phase charging is capped well below what a three phase charger can deliver.
• A large solar system with an inverter that would otherwise be limited by single phase export rules in your distribution area.

An upgrade is not a small job. It typically involves the distributor, new service cabling from the street or the pole, a new meter and often a new switchboard, and in some cases the pit or pole equipment has to change too. That is why the honest answer for most homes is that load management on a single phase supply is cheaper and does the same job.