Simplified cable selector
Basahin ang Appendix C device rating at voltage drop tables.
Reads AS/NZS 3000:2018. Tables checked 26 Sept 2026.
Subukan ang isang job 6
Nilalagyan ng halimbawang value ang bawat job. Palitan ang mga ito ng sarili mong value.
- Match a breaker to a 2.5 mm² cableThe largest breaker for a 2.5 mm² cable partly in ceiling insulation over 30 m.
- Match a breaker to lighting cableThe largest breaker for 1.5 mm² over 35 m.
- Match a breaker to 4 mm²The largest breaker for 4 mm² over 25 m.
- Match a breaker to oven cableThe largest breaker for 6 mm² over 15 m.
- Check a three‑phase 10 mm² circuitThe largest breaker for 10 mm², three phase, over 40 m.
- Match a breaker in full insulationThe largest breaker for 2.5 mm² fully in insulation.
Mga input
Worked example gamit ang mga default na input.
- Cable size
- 2.5 mm²
- Mga phase
- Single phase, 230 V
- Kondisyon ng installation
- Walang enclosure sa hangin
- Design current
- 20 A
- Haba ng ruta
- 25 m
- Limit ng voltage drop
- 5 %
Pinakamataas na rating ng device
25A
- Voltage drop
- 3.91%
- Ampere metro
- 500
- Sukatin para sa drop limit
- 2.5mm²
Design aid lang ang resultang ito. I-verify ito laban sa kasalukuyang standard.
Mga hakbang ng kalkulasyon
- Pinakamataas na device rating InResulta25A
AS/NZS 3000:2018 Tables C6 and C7
- Ampere metro500
AS/NZS 3000:2018 Table C8
- Ampere metro bawat porsiyento para sa laking ito128
AS/NZS 3000:2018 Table C8
- Voltage drop3.91%
AS/NZS 3000:2018 Table C8
- Ampere metro bawat porsiyento na kailangan para sa limitasyon100
AS/NZS 3000:2018 Table C8
- Pinakamaliit na laki para sa limit ng voltage drop2.5mm²
AS/NZS 3000:2018 Table C8
Tungkol sa calculator na ito
How this is calculated
The tool reads the simplified tables of AS/NZS 3000 Appendix C. They cover copper cable from 1 mm² to 25 mm². They give the largest device rating and the voltage drop in one pass.
- Maximum device rating. The tool reads the rating for your size, phases and installation condition from Tables C6 and C7.
- Ampere metres. It multiplies the load current by the one-way length.
- Ampere metres per percent. It reads the value for your size from Table C8.
- Voltage drop. It divides the ampere metres by that value. The result is the drop in percent.
- Size for the limit. It divides the ampere metres by your limit. It then picks the smallest size from Table C8 that meets the figure.
| Step | Table or clause | What it decides |
|---|---|---|
| Device rating | AS/NZS 3000 Tables C6 and C7 | The largest device for the size and condition |
| Drop and size | AS/NZS 3000 Table C8 | The drop for the run and the size for your limit |
Worked example
- 2.5 mm² on one phase over 25 m at 20 A. The cable is in unenclosed air. The maximum device rating is 25 A. The run is 500 ampere metres. The drop is 3.91 %, inside the 5 % limit. The size for the limit is 2.5 mm².
Limits
The tables assume one circuit on its own. Where circuits are grouped, use the cable size calculator. The tool does not apply correction factors. It does not read AS/NZS 3008.1 tables. It stops at 25 mm².
See also: Cable size for a 32 A single‑phase run of 25 m, AS/NZS 3000 Clause 3.6.2 voltage drop limit and Voltage drop basics.
Mga tanong
Design aid ang resulta. I-verify ito laban sa kasalukuyang standard.
Ano ang ginagawa ng Simplified Selector?
Binabasa ng tool ang AS/NZS 3000:2018 Tables C6 at C7 para sa pinakamalaking protective device na puwedeng dalhin ng cable na 1 hanggang 25 square millimetre. Pagkatapos, binabasa nito ang Table C8 para sa voltage drop sa run at sa pinakamaliit na laki na nakakatugon sa limit.
Kailan ko dapat gamitin sa halip ang full cable size tool?
Gamitin ang cable size tool kapag naka-group ang mga circuit, kapag hindi 30 degrees ang ambient temperature, kapag hindi PVC two‑core o four‑core and earth ang cable, o kapag higit sa 25 square millimetre ang laki. Ipinapalagay ng Appendix C na iisang circuit lang ang nasa sarili nitong.
Paano kinakalkula ang voltage drop?
I-multiply ang design current sa haba ng ruta para makuha ang ampere metres. Hatiin iyon sa ampere metres per percent para sa laki sa Table C8. Ang sagot ay ang voltage drop bilang porsyento ng 230 volts single phase o 400 volts three phase.
Aling installation condition ang dapat kong piliin?
Itugma ang paraan ng pagkakalagay ng cable. Ang cable na naka-clip sa free air ay binabasa bilang unenclosed. Ang cable sa conduit, duct o wall cavity ay binabasa bilang enclosed in air. Ang buried run ay binabasa bilang enclosed in ground. Ang insulation sa paligid ng cable ay binabasa bilang partly o completely surrounded. Ibinibigay ng Note 3 sa Table C6 ang buong mapping.
Mga clause at table na binabasa ng tool na ito
- AS/NZS 3000:2018 Table C6, C7Simplified protective device selection for 1 to 25 mm² cables
- AS/NZS 3000:2018 Table C8Simplified voltage drop, ampere metres per percent
Bawat clause at table, kasama kung paano ito na-verify
Huling na-check ang mga table noong 26 Sept 2026.
Mga kaugnay na tool
- Cable size calculatorFind the smallest cable size that passes each check.AS/NZS 3008.1.2AS/NZS 3008.1.1AS/NZS 3000
- Pagsusuri ng umiiral na circuitCheck an installed circuit: cable, device, drop and Zs.AS/NZS 3008.1.2AS/NZS 3008.1.1AS/NZS 3000
- Full load current calculatorCalculate full load current from power, voltage and phase.Walang standard
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