Single-phase vs three-phase solar
Your power supply decides how big a solar system can be. Here's how to tell which you have, the usual limits in Victoria, and when an upgrade makes sense.
Updated November 2026 · Litmec Electrical, REC-10383
Most Melbourne homes are single phase. Distributors in Victoria usually allow up to about 10 kW of inverter on single phase, with exports limited to about 5 kW. Panels can be sized up to a third larger than the inverter.
Three-phase homes can usually take larger systems, which matters with big roofs, pools, electric cars and all-electric homes. Exact limits depend on your distributor and are confirmed in the connection application.
How to tell which you have
- Main switch: at the switchboard, a single main switch usually means single phase; three switches joined together, or one wide three-pole switch, usually means three phase.
- Meter: three-phase meters often show three sets of readings or an "L1 L2 L3" display.
- Ask us: we check on the site visit.
Typical limits
| Supply | Inverter, usually up to | Export, usually up to | Panels on that inverter |
|---|---|---|---|
| Single phase | about 10 kW | about 5 kW | up to about 13 kW |
| Three phase | about 30 kW (10 per phase) | set by distributor | up to about 40 kW |
Does a single-phase home need to upgrade?
Usually not. A 6.6 to 10 kW system covers most households. An upgrade to three phase starts to make sense when you add several large loads at once: a big system plus a battery, plus an EV charger, plus ducted heating or a pool. Then one supply upgrade done properly beats three separate fixes.
Three-phase conversions are done by our own electricians and coordinated with your distributor. See three-phase upgrades on our main site.
Export limits and clipping
An export limit caps what flows to the grid at any moment, not what the panels make. Power you use in the house is never limited. On a sunny midday a large single-phase system can be clipped; batteries, daytime loads and east-west layouts all reduce it.
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Questions
How big a solar system can I put on single phase in Victoria?
Usually up to about 10 kW of inverter, with exports limited to about 5 kW, and panels up to about a third larger than the inverter. Your distributor confirms the limit when the connection is applied for.
Do I need three-phase power for solar?
No. Most homes have single phase and a 6.6 to 10 kW system suits them. Three phase helps when you need a larger system, a battery and an EV charger together.
How do I know if my house is three phase?
Look at the main switch: three linked switches or a wide three-pole switch usually means three phase. An electrician can confirm on the site visit.
Check it on your roof
One minute online, then a free visit from a licensed electrician who checks your roof and switchboard.