Calculators
Cable sizing, voltage drop, maximum demand and LED spacing. Each one runs on the current Australian Standards, with the derating factors and limits built in. No spreadsheets, no guesswork, a result you can stand behind.
Try the calculators freeThe calculator suite
The calculations an electrician reaches for on a job, each grounded in the standard it answers to.
Picks the minimum cable that satisfies current carrying capacity, voltage drop and short circuit at once.
AS/NZS 3008Works the total drop across consumer mains, submains and the final subcircuit, against the Wiring Rules limit.
AS/NZS 3000Adds your loads and applies the diversity factors, so the main switch and submains are sized correctly.
AS/NZS 3000Returns the fitting count and grid layout to hit a target lux level across the room evenly.
AS/NZS 1680Grounded in the standards
A calculator is only as good as the standard behind it. Every result here is worked against the current Australian Standards, with the derating factors and limits built in, so the number you get is the number you can put on a compliance note.
Cable selection follows AS/NZS 3008.1.1. Current-carrying capacity is not a single tabulated figure: it is derated for the installation method, for grouping with other circuits, for ambient temperature, and for thermal insulation. Thermal insulation is the factor most often missed on site. A cable that carries a circuit comfortably in free air can fall short once it runs through a fully insulated ceiling.
Voltage drop is the second calculation, and AS/NZS 3000, the Wiring Rules, caps the total drop from the point of supply across the consumer mains, submains and final subcircuit combined. On a long run, voltage drop, not current capacity, decides the cable size. The cable you install has to satisfy both calculations: the larger answer wins.
For the full explanation of how the two calculations fit together, read the guide to cable sizing and voltage drop under AS/NZS 3008.
Why it matters
A calculation done at the quote is a calculation that saves a reorder, a callback and a hard conversation later.
Run the numbers at quoting, not after the reel is on the truck. A cable that falls short on a long run is a reorder and a return.
Every figure is worked against the current standard, with the derating and the limits built in. The number you read is the number you can sign behind.
No formulas to keep current, no tabs that break when a tab is renamed. Open the calculator, enter the job, read the answer.
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