Two-phase properties can run Sigenergy hardware. That is the short finding from two technical documents Sigenergy issued in mid-2025: a Declaration of Two-Phase Operation Compatibility from the Sigenergy service team (May 2025) and a two-phase design scenarios overview (V2, dated 7 June 2025). I have been through both, and the details matter more because the answer splits in two depending on the type of two-phase supply the property has. One route preserves whole-site backup at reduced output. The other limit is that backup is limited to a single phase. This analysis walks through what each document permits, what it rules out, and where the design limits sit.
TL;DR
- Sigenergy systems install on two-phase supplies, but the supply type dictates the hardware pathway
- 415V two-phase sites (120° phase shift) can run the 3-phase SigenStor EC with the 3-phase Gateway, with output limited to two-thirds of rated capacity
- 480V split-phase and SWER-derived sites (180° phase shift) use the single-phase pathway, with backup available on one phase only
- The 3-phase option requires firmware V100R001C21SPC108 or higher
- 3-phase generators are not compatible with any two-phase Sigenergy configuration
Contents
What a two-phase supply is
A two-phase supply delivers two live conductors and a neutral to the property instead of one (single-phase) or three (3-phase). In Western Australia it shows up in two distinct forms, and they are not interchangeable.
The first is 415V two-phase, where the property receives two of the three phases from a standard 3-phase distribution network. The two phases sit 120° apart, giving roughly 240V phase-to-neutral and 415V phase-to-phase. This arrangement is common on the urban fringe and in semi-rural areas where 3-phase infrastructure runs past the property but only two phases were ever connected.
The second is 480V split-phase, where a single-phase transformer splits the supply into two live conductors sitting 180° apart. Phase-to-neutral stays at 240V, but phase-to-phase reaches 480V. This is the configuration typically found on SWER (single wire earth return) networks across rural WA, where Western Power runs a single conductor over long distances and the return path is through the earth itself.
From the switchboard, both look like “two phases”. Electrically, they behave differently, and that 120° versus 180° distinction is the single most important fact in this whole topic.
Step one: Identify
which two-phase you have
Before any system design starts, the supply type needs confirming. A licensed electrician can measure the phase-to-phase voltage at the main switchboard: a reading around 415V indicates the 120° configuration, while a reading around 480V indicates split-phase. The network operator (Western Power for most of the South West Interconnected System) can also confirm the supply arrangement on record for the property.
If you’re not sure whether the property is even two-phase to begin with, the PSW Energy guide on identifying single-phase or 3-phase supplies covers the visual checks. Get this step wrong and the system design that follows is wrong. A 3-phase SigenStor configured for a 415V site will not operate on a 480V split-phase supply.
415V two-phase sites
the 3-phase Gateway
Here is the finding that surprised me. Sigenergy’s 3-phase hybrid inverters and the 3-phase Energy Gateway can operate on a site where only two phases are available, provided those phases carry a 120° shift. The May 2025 declaration confirms this formally, with one hard condition: inverter firmware V100R001C21SPC108 or higher.
During commissioning, the system detects the absence of the third phase and configures itself for two-phase operation. The control logic then limits operation to the two connected phases, protecting the power electronics and keeping delivery balanced across the live conductors.
There is a trade-off, and it’s a predictable one: with one of three phase legs unused, total output is limited to two-thirds of the inverter’s rated capacity. A 15kW 3-phase SigenStor EC operating on a 415V two-phase supply delivers a maximum of 10kW. That isn’t a fault. It’s the expected behaviour of a 3-phase machine running on two legs, and system sizing needs to account for it from the start. The configuration limits for this setup, per the design scenarios document:
Backup capacity of up to 20kVA per phase through the 3-phase Gateway
Up to 60kVA of total SigenStor capacity on a site
Supports ~230V phase-to-neutral or ~415V phase-to-phase supplies
Both neutral lines continue to the neutral bar, with earth to the earth bar link inside the Gateway or main switchboard
A 3-phase SigenSensor handles consumption monitoring
For a rural workshop or a property running 415V two-phase equipment, this configuration preserves whole-site backup across both connected phases. On my read, that makes it the stronger option wherever the supply type allows it.
480V split-phase and SWER sites
the single-phase setup
The 3-phase option does not apply here. Sigenergy specifies its 3-phase two-phase operation for the 120° shift only, so a 480V split-phase site takes a different route: single-phase SigenStor EC units paired with the single-phase Gateway, installed on one of the two legs. The single-phase Gateway itself accommodates either supply type (the design scenarios list it for both 120° and 180° shifted sites), which makes it the universal fallback when the supply type is uncertain or the 3-phase route is ruled out.
SigenStor SP units connect to one phase (L1), with backup of up to 12kVA available on that phase only
The second phase (L2) continues to operate from the grid and is net metered while the grid is up
Maximum of 12kVA total SigenStor capacity, with two breakers inside the Gateway
A 3-phase SigenSensor monitors consumption across both legs, so the system still sees whole-of-site loads
An optional single-phase diesel generator can be integrated for extended outages
The consequence is clear: during a grid outage, only the loads on the phase carrying the SigenStor stay powered. Backup cannot transfer between the phases, because the phase angle between the two legs makes cross-feeding impossible. Planning which circuits sit on the backed-up phase becomes a genuine design decision. Essential circuits (refrigeration, water pumping, communications, lighting) belong on L1 with the storage; discretionary loads can stay on L2.
Adding storage to both phases
A second SigenStor system can be installed on the other phase where backup is needed across both legs. On a 480V split-phase site the two systems cannot share a single plant in the monitoring platform, so they appear as two separate systems in the mySigen app. Installers typically name them as a pair (“Smith Family 1” and “Smith Family 2”). Functionally both systems operate normally; it’s a monitoring-structure quirk rather than a performance limitation.
Sites with existing third-party solar
An existing single-phase solar inverter from another manufacturer can coexist with the single-phase setup. The design scenarios add one condition: the third-party inverter’s capacity must not exceed the SigenStor capacity on the site. A second, single-phase SigenSensor is added to track the third-party generation alongside the 3-phase consumption sensor.
Generator compatibility
and our one firm rule
This one is worth its own section because getting it wrong can destroy equipment. A 3-phase generator must not be used with a two-phase Sigenergy configuration. Generators built for balanced 3-phase output rely on all three phases being loaded evenly. Running one with a phase unused causes unstable voltage, mechanical stress and overheating, and can permanently damage the generator. Sigenergy’s declaration states this directly, and it deserves the emphasis.
On the single-phase setup, a single-phase diesel generator is supported as an optional input through the Gateway. On the 3-phase two-phase configuration, no generator is supported at all. If generator backup is a hard requirement for the site, that constraint may decide the configuration before anything else does.
System sizing
Three design rules fall out of all the above.
Derating comes first on 415V sites. If the load assessment says the property needs 12kW of inverter capacity, a 3-phase unit needs a nameplate rating of at least 18kW to deliver it on two phases. Sizing from the nameplate without applying the two-thirds factor undersizes the system.
Phase allocation comes first on 480V sites. The backup ceiling is 12kVA on a single leg. The design conversation shifts from “how much capacity” to “which circuits matter most”, and the switchboard work to regroup essential circuits onto the backed-up phase is part of the install scope.
Firmware and commissioning matter. The 3-phase setup requires a minimum firmware version and a correct two-phase configuration during commissioning. This is exactly the category of install where who does the work matters more than what the brochure says. Whoever quotes the job should be able to tell you which option applies, what firmware the inverter ships with, and how the two-phase configuration will be verified at commissioning. If they can’t, that tells you something.
One limitation to note: both documents are current as of mid-2025, and design rules of this kind get revised. Before any design is finalised, the figures here should be checked against the latest Sigenergy AU design guidance. Two-phase properties have spent years being quoted around rather than quoted properly. The hardware now supports doing it right, and the 120° versus 180° distinction is the first question any competent design conversation should start with.
If we are unable to accommodate your two-phase power supply needs in Western Australia, we recommend contacting Off-Grid WA.
