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AS/NZS 3008.1.1:2025, the updated Australian and New Zealand cable sizing standard, was published in December 2025. The revision introduces several changes affecting current-carrying capacity tables, correction factors, installation cases, and guidance for modern power systems.
Engineers performing cable sizing calculations under AS/NZS 3008 should review these updates to ensure designs align with the latest standard. If you need a refresher on the calculation process, see our guide to AS/NZS 3008 cable sizing calculations.
DC Cable Sizing Tables Introduced
AS/NZS 3008.1.1:2025 now includes dedicated tables for DC systems.
The standard provides:
DC current-carrying capacity tables
DC conductor resistance values
DC voltage drop tables (mV/A·m)
These additions support the growing use of DC systems in applications such as solar PV, battery energy storage, and data centres.
Previously, engineers often relied on AC table adaptations or external references when performing DC cable sizing calculations. For an example of DC cable sizing in solar installations, see DC cable sizing calculations for solar PV systems.
Updated Correction Factors for Cable Grouping
Correction factor tables have been expanded to include multi-row cable group arrangements.
The standard also replaces the term “derating factor” with “correction factor.”
The new grouping tables better reflect practical installation scenarios in which cables are installed in multiple rows in trays, ducts, or racks, thereby improving the accuracy of current-carrying capacity adjustments.
Expanded Current-Carrying Capacity Tables
The 2025 edition introduces additional current-carrying capacity values, including:
Tables for 110 °C aluminium conductors
Additional conductor sizes
Expanded installation cases
These updates provide guidance for conductor types and operating temperatures that were not fully covered in previous editions.
Simplified Copper Conductor Tables
The copper current-carrying capacity tables have been simplified.
Stranded and flexible copper conductors now share the same current-carrying capacity column, eliminating the need to select separate entries for conductor construction types with effectively equivalent thermal performance.
New Installation Cases for Thermal Insulation
The standard now includes current-carrying capacity values for cables installed in conduits surrounded by thermal insulation.
These cases apply to installations where conduits are:
partially surrounded by insulation
completely surrounded by insulation
In previous editions, several table entries for these conditions were not populated.
The new tables provide guidance for installations commonly encountered in modern buildings and service infrastructure.
Voltage Rise for Export Circuits
AS/NZS 3008.1.1:2025 now formally recognises and defines voltage rise.
The standard includes guidance and worked examples for:
Generator circuits
Solar export circuits
Unbalanced multiphase systems
Voltage-rise calculations use vector (phasor) addition to assess voltage drop in unbalanced multiphase systems. If you want to understand the underlying principles, see our article explaining voltage rise calculations.
Short-Circuit Withstand Tables
The new edition introduces tabulated short-circuit withstand values for common cable types.
These tables allow engineers to quickly verify whether a cable withstands a specified fault current for a given duration, reducing the need for manual thermal withstand calculations.
For a deeper explanation of the underlying theory, see short-circuit rating calculations for cables.
Key Takeaways
The 2025 revision of AS/NZS 3008.1.1 introduces several practical updates affecting cable sizing calculations and installation assessment.
Key additions include:
DC cable sizing tables
Updated grouping correction factors
Expanded conductor and installation cases
Simplified copper current-carrying capacity tables
Voltage rise guidance for export circuits
Tabulated short-circuit withstand values
Engineers responsible for cable design and verification should review these changes when performing cable sizing calculations and ensure design tools are updated accordingly.
Frequently Asked Questions
1 — How should DC circuits be sized under AS/NZS 3008.1.1:2025?
The AS/NZS 3008.1.1:2025 edition introduces dedicated DC table sets covering DC current-carrying capacity, DC resistance, and DC voltage-drop factors. For applications such as solar PVs, batteries and DC feeders, sizing should be based on these DC tables rather than relying on AC table assumptions.
2 — What has changed in the correction factors for grouped cables?
AS/NZS 3008.1.1:2025 updates terminology from derating factor to correction factor. The edition also introduces expanded grouping tables for multi-row arrangements (stacked layers on trays, ladders, etc.). When applying grouping corrections, confirm whether the installation is single-row or multi-row and select the corresponding table.
3 — What additional current-carrying capacity data is now available in the 2025 edition?
The 2025 edition expands CCC coverage in several practical ways: Aluminium (110°C) conductor CCC values are now included in the Standard, with additional conductor sizes (0.5, 0.75 mm²). Copper CCC tables are simplified: flexible and stranded copper conductors now share the same CCC column throughout.
4 — What is “voltage rise” in AS/NZS 3008.1.1:2025, and when should it be assessed?
The 2025 edition explicitly addresses voltage rise for circuits that export power to the network (e.g., PV inverter feeders), including guidance and worked examples. In these cases, the same conductor impedance that causes a voltage drop under load can produce a rise under export, and the design should verify compliance under the expected export conditions.
5 — What is the intent of the short-circuit tables included in AS/NZS 3008.1.1:2025?
The 2025 edition includes tabulated short-circuit withstand information for common cable types/sizes as a quick reference. These tables support rapid screening and design validation, but final suitability should still be confirmed against the project’s fault level and calculated using the adiabatic equation.
6 — What is the scale of change in AS/NZS 3008.1.1:2025 compared with the 2017 edition?
In total, the preface lists 23 discrete changes. Compared with AS/NZS 3008.1.1:2017, the 2025 edition makes major changes: it renumbers, adds to, and extends existing current‑carrying tables, and includes new DC tables and new 110°C aluminium ratings. It updates existing correction factor values and adds new correction factor tables (especially for multi‑row grouping), broadens the voltage drop section to cover DC and voltage rise calculations with new DC resistance tables, and reorganises the short‑circuit section with new tabulated withstand values, while keeping the core adiabatic and voltage‑drop equations broadly consistent.
