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Single-Phase vs Three-Phase Solar and Batteries

Short answer. Single-phase homes have one live wire coming in, three-phase homes have three. Phase decides which inverter and battery models fit and whether a battery can back up the whole home. We confirm yours on the site visit, and both Sigenergy and GoodWe offer single-phase and three-phase systems.

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Phase is one of the first things we check on a site visit, because it decides which inverter and battery models fit and what a battery can back up in a blackout. It is easy to find out, and it does not need to put you off.

What single-phase and three-phase mean

Single-phase supply brings one live conductor into your home. Three-phase brings three. Most Northern Rivers homes are single-phase. Three-phase is more common on larger homes, rural properties with big sheds or pumps, and commercial sites. A three-phase supply can share the load across its three phases, which suits big motors, ducted air conditioning and three-phase EV chargers.

Sigenergy home battery installed by Sun Connect Solar, approved Sigenergy battery installer in the Northern Rivers NSW
A Sigenergy home battery installed by our own electricians. Single-phase and three-phase versions of these systems exist.

How to tell what you have

  • Look at the switchboard, without opening it. A one-pole main switch usually means single-phase. A three-pole main switch, or three linked switches, usually means three-phase.
  • Check the meter and your bill. The supply details on a power bill and the markings on the meter can show the phase count.
  • Look at the street connection. Three-phase connections have more conductors running from the pole to the house.
  • Ask us. If you are unsure, tell us on the call and we confirm it on the site visit. Please do not open the switchboard or the meter box yourself.

What it changes when you add solar

  • Inverter choice. Single-phase homes use single-phase inverters. On three-phase, we choose between a three-phase inverter and single-phase units, depending on size and on what you want to back up.
  • Export. Export limits and connection rules are set per connection by Essential Energy, so the phase count can change what is allowed. Your connection offer is what counts. See solar export limits in the Northern Rivers.
  • Balance. On three-phase, spreading solar across the phases rather than loading one of them is part of good design.

What it changes when you add a battery

The key point is backup. A single-phase battery on a three-phase home can only supply the circuits on the phase it is connected to, so in a blackout the other circuits stay off. If you want the whole home on, we usually look at a three-phase battery. If you are happy with essential circuits, we can sometimes group them onto one phase. See whole-home versus essential-circuits backup.

Sigenergy and GoodWe

Sigenergy. The SigenStor range comes in single-phase and three-phase versions, with matching backup gateways. See our Sigenergy page.

GoodWe. The ESA all-in-one range is made in single-phase versions and in three-phase versions with larger inverter sizes. See our GoodWe page.

Model names, sizes and approvals change often. We check the current datasheet for the exact model, and its compatibility with your supply, before we put it in a proposal. We also install Sungrow, Solax and Tesla systems, and the same phase questions apply.

How we handle it on our jobs

  1. On the free energy assessment call we ask if you know your phase. If not, no problem.
  2. On the face-to-face site visit we confirm it, check the switchboard (including any RCBO upgrades needed to meet current safety standards) and note what you want to keep running in a blackout.
  3. We then choose the inverter and battery model to suit, and tell you what that means for backup, in plain language, before you decide.

Our own electricians do all of the work, and our background is 25 years in solar and large commercial electrical work, so three-phase boards are routine. See also switchboard upgrades and RCBOs.

Questions we get asked

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

Look at the main switch in your switchboard. A single-phase home usually has one main switch, and a three-phase home has a three-pole main switch or three linked switches. The supply details on your power bill and the markings on your meter also help. Please do not open the board yourself. We confirm it on the site visit.

Can I put a single-phase battery on a three-phase home?

In many cases, yes, but a single-phase battery can only back up the circuits on the phase it is connected to. If you want the whole home backed up on a three-phase supply, we normally look at a three-phase battery system instead.

Does three-phase mean I need a bigger solar system?

No. Three-phase is about how your supply is wired, not how much solar you need. We size solar from your usage. Phase does affect which inverter and battery models suit, and how solar is balanced across the phases.

Do Sigenergy and GoodWe both come in three-phase?

Both brands list single-phase and three-phase versions of their home systems. Exact models and sizes change, so we confirm the right one for your supply and your loads on the site visit rather than quote from memory.

Can I convert from single-phase to three-phase?

Sometimes. It is a network and electrical job rather than a solar job, and it depends on what is available in your street. We tell you if it is worth pursuing for your project.

Sources

Last checked 6 October 2026. Manufacturer product ranges change. We do not rely on this page for a specific model and always check the current datasheet.

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