Most homes and small businesses do not need everything on this page. They need one job done well. So here is what each common three phase job actually involves, who it suits, and what to ask a licensed electrician before any work begins.
Every job below depends on your load, the existing wiring and where the property is heading. A licensed electrician should assess the site before any figure is discussed.
Bringing a three phase supply into a property for the first time, or wiring a new build ready for it from day one. This suits larger homes, workshops, and any site planning big loads now or shortly.
Existing properties already on single phase that have outgrown it. The supply is converted, the circuits are balanced, and the board is labelled so the next person can read it.
Older ceramic fuses and worn boards are a common cause of nuisance trips and a frequent gap in a safety inspection. A switchboard upgrade replaces the board, fits modern protection devices, and tests every circuit.
Whole of home comfort should be designed around the floor plan rather than a standard kit dropped in. A system should be sized honestly, so it runs efficiently instead of fighting the house. If you are weighing up options, this guide to ducted air conditioning is a useful starting point.
Electric vehicle chargers draw a lot of power, often for hours at a time. Whether a home can support one on its existing supply, or needs a three phase upgrade first, depends on the charger rating and everything else running at the same time.
Solar inverters and batteries are wired into the switchboard, and the size of the system has to sit within the capacity of the supply and the board. Three phase can allow a larger system and better balance across the phases.
Many welders, hoists, compressors, saws and larger machine tools are built for three phase power and simply will not run on single phase. The circuit, protection and isolation all need to suit the machine.
Beyond the big ticket jobs, three phase properties still need the ordinary work that keeps a site running safely.
Powerpoints, lighting, ceiling fans, smoke alarms, outdoor and shed wiring, fault finding, and safety switches. Straightforward work that should always be done by a licensed electrician.
Fit outs, three phase machinery connections, distribution boards, emergency and exit lighting, and maintenance programs for retail, warehouse and office spaces.
Scheduled inspection and tagging for businesses that need records on file, plus fault calls when something stops working and downtime is costing money.
It is not a mystery job. Here is how it usually runs from your first enquiry to the moment the supply is switched on.
A licensed electrician looks at what you currently run and what you plan to add, then decides whether three phase is genuinely the right answer or whether another fix is cheaper.
A clear scope: what is included, what the supply authority charges, and any provisional items that depend on what is found once the board is open.
A three phase upgrade involves more than one party. Your electrician handles the paperwork and scheduling with your energy provider so you are not chasing phone queues.
Mains, meter box, switchboard and circuit distribution are set up and balanced across the three phases so no single phase carries the whole property.
Every circuit gets tested, the board gets labelled, and you receive the certificate of electrical safety plus a plain English walkthrough of what changed.
The honest answer depends on your load, not on how the job is marketed. This is the comparison worth running through with your electrician.
| Consideration | Stay single phase | Upgrade to three phase |
|---|---|---|
| Typical household | Standard lighting, powerpoints, one split system, no plans to add heavy loads. | Multiple large air conditioners, EV charging, pool pump, workshop tools. |
| Switchboard | Sound board with RCD protection already fitted. | Old fuses or a board that is out of spare ways and overdue for replacement. |
| Air conditioning | Single split system sized comfortably within existing capacity. | Ducted system covering the whole home, or several zones cooling at once. |
| Ongoing nuisance | No recurring tripping when appliances start together. | Mains tripping when the oven and air con run at the same time. |
| Best time to do it | Before adding any new high draw equipment. | Alongside a renovation, new build, or major appliance purchase. |
These questions apply to every job on this page, large or small.
Three phase jobs tend to fall into a few broad categories, and the same kinds of questions apply to each.
The right approach depends on your load, your existing board and what your energy distributor allows. That is why the assessment always comes before the quote, and why the licence check always comes before the work.
Short answers to the things people want to know before booking an electrician.
Describe what you are trying to run to a licensed electrician and ask whether it needs three phase, a board upgrade, or a simpler fix. Always check their electrical contractor licence number before any work begins.