AS/NZS 3008.1.1:2025 is the fourth edition of the Australian part of AS/NZS 3008.1. It replaces the 2017 edition. This page lists what changed and runs four circuits on both editions.
In AmpSize, set the Standard select to AU. Then pick 2017 or 2025 in the Edition select. A link or a saved calculation with no edition reads 2017, so an old result keeps its numbers.
What changed
The Preface lists the changes. In AmpSize's words, they fall into nine groups.
- d.c. to 1500 V. The part now covers d.c. circuits up to 1500 V d.c., as well as a.c. to 0.6/1 kV. Tables 3.21 to 3.26 give d.c. ratings for two single‑core cables and for 2‑core cables. The DC cable size calculator reads them.
- New table numbers. Each table now takes the number of its section. Table 13 is now Table 3.18. Table 22 is now 3.33, Table 27 is now 3.44 and 3.45, and Table 52 is now 5.1.
- One copper column set. The flexible and the non‑flexible copper columns are now one set. Each rating table has 20 columns: 10 installation methods, each for copper and aluminium.
- Small buried cables. A calculation to the IEC 60287 series now sets the buried-direct ratings up to 10 mm². These ratings rise in every a.c. rating table that AmpSize reads.
- Large enclosed cables. Ratings for cables enclosed in air or partly in insulation now reach 630 mm² for two single‑core cables. Multicore ratings reach 500 mm². The 2017 edition printed a dash at those sizes.
- Ambient, depth and grouping. A new method derives the ambient air and soil factors. The depth factors now follow ERA 69-30 Pt III, and some of them change. Two grouping factors change, at 7 and 8 circuits in one touching layer.
- k to one more figure. Table 5.1 gives k with one more significant figure than 2017 did.
- d.c. resistance and voltage drop. Tables 4.6, 4.8 and 4.11 give d.c. resistance. Tables 4.16, 4.18, 4.21, 4.23, 4.26 and 4.28 give d.c. voltage drop in mV/A.m.
- A new name. The edition says correction factor (derating factor in 2017). This page uses correction factor from here on.
The a.c. resistance and reactance values that AmpSize reads are the same in both editions. So an AU voltage drop result does not change with the edition. For example, 16 mm² multicore copper at 50 A over 60 m, three phase, drops 1.69 % on the 2017 edition and on the 2025 edition.
Four circuits on both editions
Each circuit has two links. The first opens it on the 2017 edition, and the second on the 2025 edition. Every figure comes from the calculator.
1. A small cable buried direct. The inputs are 400 V three phase, 30 A and 20 m. The cable is multicore copper with PVC insulation, buried direct in soil at 25 °C.
- 2017: 2.5 mm² carries 25 A, which is less than 30 A. The calculator selects 4 mm² at 33 A.
- 2025: 2.5 mm² carries 34 A. The calculator selects 2.5 mm². The voltage drop is 2.12 %.
- The 2025 result adds a note. Check that the protective device lets the cable reach its rating.
Open on 2017 and open on 2025.
2. A hot roof space. The inputs are 230 V single phase, 63 A and 20 m. The cable is multicore copper with PVC insulation, unenclosed and touching, in air at 45 °C.
- 2017: the correction factor is 0.91. 16 mm² carries 61.88 A, which is less than 63 A. The calculator selects 25 mm² at 82.81 A.
- 2025: the correction factor is 0.93. 16 mm² carries 63.24 A and passes. The calculator selects 16 mm². The voltage drop is 1.42 % and the earth conductor is 6 mm².
Open on 2017 and open on 2025.
3. A large submain enclosed in air. The inputs are 400 V three phase, 400 A and 30 m. The cable is multicore copper with XLPE insulation, enclosed in air at 40 °C.
- 2017: no single cable passes. 240 mm² carries 386 A, and the larger sizes have no rating.
- 2025: the calculator selects 300 mm² at 437 A. The voltage drop is 0.53 %.
Open on 2017 and open on 2025.
4. Fault withstand. A 10 kA fault clears in 0.1 s on 35 mm² copper with PVC insulation.
- 2017: k is 111. The minimum size is 28.49 mm², so 35 mm² passes.
- 2025: k is 111.2. The minimum size is 28.44 mm², so 35 mm² passes.
- The size changes only when the minimum sits very close to a standard size.
Open on 2017 and open on 2025.
On 2025, circuits 1 and 2 take a smaller cable, and circuit 3 finds a cable. A grouped circuit can need a larger cable on 2025. Run your own circuit on both editions before you change a design.
Dates and the transition
- The New Zealand Standards Approval Board approved the edition on 5 November 2025.
- Standards Australia approved it on 2 December 2025.
- The publication date is 19 December 2025.
- The Preface says that regulators indicated a six-month transition from the date of publication.
Ask your regulator whether the transition applies to your work, and when it ends. Also ask whether a design that started on 2017 can finish on 2017.
AS/NZS 3008.1.1 is the Australian part. For New Zealand, AmpSize reads AS/NZS 3008.1.2:2017.
How to keep a design reproducible
Each step of a result names the edition and the table it read. The 2025 steps give the new numbers, such as Table 3.18 and Tables 3.44 and 3.45.
- Write the edition beside the size in the cable schedule. A size alone does not say which data set it came from.
- Keep a 2017 design on 2017. Open its saved link, and the result does not move.
- Run a new design on 2025, then compare it with 2017 on the same inputs.
The standards page lists the 2025 tables and clauses that AmpSize reads. The glossary defines the correction factor. The page on current-carrying capacity and derating explains how the factors combine.
This page is a design aid. Verify every value against the current edition of the standard.