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Identification Tool

Single or Three-Phase Supply Check

Use visible main-switch or meter clues to identify a likely single- or three-phase supply without opening the switchboard.

Sources listedReviewed July 2026Our methodology

Inputs

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Look but don’t touch. Switchboards carry mains voltage.

Live result

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Likely supply

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Key takeaways
  • Uses a visible main-switch or meter clue to identify the likely existing supply.
  • Does not recommend a supply upgrade or infer network connection limits.
  • Keeps the check external to the switchboard and directs uncertain users to a licensed electrician.

How it works

This check identifies a likely existing supply from one of two visible clues, without opening or touching the switchboard:

  • Main switch width. A narrow, single-pole main switch is single-phase; a wide, three-pole (ganged) switch is three-phase.
  • Active wires at the meter. One active conductor (plus neutral) is single-phase; three actives is three-phase.

The result is an identification aid, not a recommendation to change the supply and not a network-connection assessment. Confirm the supply and the applicable inverter or export conditions from the network information or with a licensed electrician. If you can't tell, send your electrician a photo taken from a safe position. Never open the switchboard yourself.

Estimates only: for guidance, not a quote or a compliance certificate. Verify against the current AS/NZS standards and a licensed design. The maths runs in your browser. Nothing is sent to Wattbench unless you sign in and deliberately save the result.

Source ledger2 sources

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Frequently asked

Is this tool free to use?
Yes. The phase checker is free and needs no sign-up. It runs entirely in your browser.
Is my data stored or sent anywhere?
The calculation runs in your browser. Nothing is sent to Wattbench unless you sign in and deliberately select Save result.
Why does single or three-phase matter for solar?
The existing supply is one input to inverter connection and export design. This tool only identifies the likely supply from a visible clue; it does not recommend a phase or determine network limits.
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