What Is Three-Phase Power — and Do You Need It for Solar, a Battery or an EV Charger?

Three-phase power means your home is fed by three live wires instead of one, so it can carry a bigger electrical load. Single-phase has one live wire and is the normal supply for most Tasmanian houses. Three phases don’t make your power “better” — they just give you more capacity to work with.

A handy way to picture it: single-phase is one lane of traffic, three-phase is three lanes. Most households never fill the one lane they have.

Three-phase is more common in newer homes, large homes and rural properties. Older homes around Hobart, Launceston and regional Tasmania are usually single-phase, and that’s completely normal.

How do I tell if my house is single-phase or three-phase?

Open your meter box and look at the main switch. One pole (one switch body) usually means single-phase. Three poles linked together so they flip as one means three-phase. That 10-second look answers the question for most people — no electrician needed just to check.

If your meter box is old, crowded or hard to read, don’t force anything. An installer or electrician will confirm it as part of any site inspection, and they’ll also note whether your switchboard has room for new circuits.

Do I need three-phase power for solar panels in Tasmania?

Almost certainly not. TasNetworks allows a 10 kW single-phase inverter in Tasmania, which covers a system of around 13 kW of panels under the 133% inverter oversizing rule. That size is a sensible, future-proof default for a household heading towards an EV, a heat pump and induction cooking.

So the common worry — “I’ll have to upgrade my whole supply to go solar” — doesn’t apply to most Tasmanian homes.

Where three-phase does come into it is at the top end. Inverters above the single-phase limit may require a three-phase supply, and that limit varies with the equipment and the connection, so it’s a question for your designer rather than a number to memorise.

And if your household genuinely uses very little power, has no battery, no EV and no electrification plans, a smaller system may suit you better. Bigger isn’t automatically smarter.

What is an inverter?

The inverter is the box that converts the DC electricity your panels make into the AC electricity your house and the grid use. It’s the brain of the system: it manages output, talks to your monitoring app, and shuts down safely during a grid fault.

It’s also the component that decides whether you’re a single-phase or three-phase job. Panels don’t care about phases; inverters do.

Do I need three-phase for a home battery?

No. Typical home solar-and-battery combinations in the sizes most Tasmanian households install run on single-phase without any supply upgrade. Batteries are usually matched to your evening and overnight usage, not to your supply type.

Being honest about batteries in Tasmania: our power is relatively cheap and Aurora Energy’s regulated feed-in tariff is comparatively fair — 9.276 c/kWh from 1 July 2026, up from 8.782 c/kWh in 2025-26 — so the economics here move more slowly than on the mainland. The federal Cheaper Home Batteries Program, which began on 1 July 2025 and tapers each year to 2030, discounts an eligible battery where the eligibility conditions are met, and the battery must be paired with solar. There is no separate Tasmanian state battery rebate.

For most Aurora-tariff households, battery value comes from self-consumption and outage backup rather than trading. No vendor or retail VPP program operates in Tasmania, though wholesale-price exposure does exist through spot-passthrough retailing, and automated control can charge a battery when spot prices go negative and avoid peak imports. Solar Generation Tasmania runs exactly that setup on its own systems.

Do I need three-phase for an EV charger?

This is the one case where the answer is sometimes yes. A 7 kW charger works fine on single-phase and suits overnight charging at home. A 22 kW charger needs three-phase — there’s no way around it.

What you’re adding	Single-phase	Three-phase needed?
Solar up to a 10 kW inverter (~13 kW of panels)	Yes, fine	No
Typical home battery	Yes, fine	No
7 kW EV charger	Yes, fine	No
22 kW EV charger	No	Yes
Inverters above the single-phase limit	No	Yes

Before assuming you need 22 kW, do the maths on your own driving. A 7 kW charger running overnight adds a lot of range by morning, and most households plug in at home far more often than they realise.

What is tariff 93?

Tariff 93 is Tasmania’s default residential time-of-use tariff. Since 1 July 2024, every new or upgraded residential connection is assigned to it. It applies whole-of-home, with peak periods on weekdays 7-10am and 4-9pm (8-11am and 5-10pm during daylight saving) and everything else off-peak, including all weekend.

The older pair are Tariff 31 (general light and power, flat rate) and Tariff 41 (separately metered lower flat rate for hard-wired heating and hot water). Both closed to new installations on 30 June 2024, though existing homes may stay on them. Neither is time-of-use.

Then there’s Tariff 97, the newer opt-in residential consumer energy resources tariff for homes with solar, a battery or an EV. It’s worth knowing about here because of two details:

It is the only Tasmanian residential tariff with a super off-peak rate, midnight to 4am every day, weekends included — which lines up neatly with overnight EV charging.
Its peak is weekdays 7-10am and 4-10pm, an hour longer in the evening than Tariff 93.
All other times are off-peak, and it carries an excess demand charge above 8.5 kW.

That last point is the real link to three-phase. A high-powered charger can push your household demand well past 8.5 kW in a single moment, so if you’re on Tariff 97 the charger’s size affects your bill structure, not just your wiring. Tariff 97 is not a controlled-load or hot-water tariff — that’s Tariff 41 — and whether a Tariff 97 retail plan is available to you depends on your retailer.

Whichever tariff you’re on, the underlying logic is the same: with imported power running at roughly 28-30 c/kWh against that single-digit feed-in rate, using your own solar at home beats exporting it.

Can I get three-phase added to my house?

Yes, usually — it’s a TasNetworks supply upgrade, arranged through a licensed electrical contractor. Cost varies enormously depending on what’s available in your street and how far the supply has to run, so a site-specific quote is the only reliable guide. Treat any figure you hear second-hand as meaningless.

If I already have three-phase, does that change my system design?

A little, and in your favour. Solar and batteries can be connected across the phases, and your designer will balance the loads so no single phase does all the work. The technical detail is installer territory — you don’t need to manage it.

The practical takeaway

Work backwards from what you actually plan to plug in:

Check your main switch — one pole or three. Now you know what you’ve got.
Solar and a battery? Single-phase is almost certainly enough.
EV? Decide between a 7 kW and a 22 kW charger before you price any supply upgrade. That one decision is what makes three-phase relevant or irrelevant.
Ask your retailer which tariff you’re on and whether Tariff 97 is available to you, especially if you’re adding an EV.
Never budget from a rumour. If a supply upgrade is genuinely needed, get it quoted for your address.

The short version: three-phase power is a capacity question, not a quality one, and for the large majority of Tasmanian homes going solar, single-phase does the job.

This free community guide is written by the Tasmanian solar team at Solar Generation Tasmania, who are always happy to answer questions from fellow Tasmanians working through these decisions.

#solargentas #solargen #solargenerationtasmania

Published by Solar Generation Tasmania. General information current as at publication — rebates, tariffs and prices change, so confirm current figures before deciding.