“Are you single phase or three phase?” is one of the first questions we ask when someone calls us about a battery — and it’s usually met with a pause. Fair enough. Most homeowners have never had a reason to know the answer, and it’s not written anywhere obvious on your bill.

Here’s why it matters, and how to find out in under two minutes.

What “phase” actually means

Australian homes are supplied with either one, two, or three “phases” of electricity from the grid. Think of each phase as a separate lane of power arriving at your switchboard. Most suburban homes run on single phase — one lane, which is plenty for lighting, appliances, and a standard air conditioner. Larger homes, homes with bigger air conditioning systems, or homes with certain solar setups often run on three phase — three lanes, giving access to more total power and better load balancing.

Neither one is “better” in a general sense — it depends on what your home actually needs. But it changes what battery equipment is compatible with your switchboard, and sometimes what work is required to get there.

Why it matters for a battery

Some battery inverters are single-phase only. Others are three-phase, or can be configured either way. If you’re on three-phase power and your installer quotes you a single-phase-only inverter without asking, one of two things happens: either they haven’t checked properly, or you’ll end up with a system that only manages part of your home’s load — which limits how much backup power and bill savings you actually get.

There’s also a practical question of where your solar and battery sit relative to your phases. If your solar panels are connected to one phase and your heaviest evening loads (like ducted air conditioning) are on a different phase, a single-phase battery might not be able to offset the usage you actually want it to offset. This is exactly the kind of detail that separates a proper site assessment from a desktop quote emailed to you sight unseen.

How to check which one you are

You don’t need to guess. Here are the three fastest ways to find out:

1. Look at your main switchboard. Three-phase homes typically have three main circuit breakers side by side (often larger, and sometimes labelled A/B/C or R/W/B). Single-phase homes usually have one main breaker.
2. Check your meter. Three-phase meters generally have more terminals and are visibly larger than a standard single-phase meter.
3. Check your bill. Some retailers note “phase” or “supply type” on your electricity bill or in your account portal — though not all do, which is why the switchboard is the most reliable check.

If you’re still not sure, that’s completely normal — and it’s exactly why “not sure” is a valid answer on our enquiry form. We’ll confirm it during your site assessment rather than making you guess.

The bigger picture

Phase type is one of several things that genuinely changes what system suits your home — alongside your existing solar size, your average quarterly bill, and how much backup you actually want during an outage. None of it is complicated once someone walks you through it, but it’s also exactly the kind of detail that gets skipped over in a rushed sales call focused on getting a signature before you’ve had time to think.

If in doubt, send us a photo of your switchboard and meter box — it takes us seconds to confirm, and it means your quote is based on what your home can actually support, not a generic assumption.