The electrical industry is on the verge of getting an update to the Wiring Rules. Lucy Finlay explains what the relevant committees are focusing on and what it might change for electricians.

Six months have transpired, and no less than 65 working group and technical committee meetings have been held since I outlined the strategy of EL-001 in delivering the next edition of AS/NZS 3000, the Wiring Rules.

In addition to the main technical committee, five separate working groups were established to make contributions on specific topics. EL-001 set a very ambitious target to publish the next edition by mid-2027. To achieve this target, the draft needs to be released for public comment before the middle of next year.

If this target is not met, it won’t be through lack of planning or effort. It’s important that EL-001 hits this target. As I have previously written, the nature of the electrical installation is rapidly changing.

While the capacity of solar systems continues to increase in both domestic and commercial installations, the continued electrification of all buildings is generating increased electrical demand.

At the same time, the cheaper home batteries program has seen demand for batteries soar. It’s not surprising to also see the average size of battery systems increasing to 17kWh, according to Solar Quotes. The demand for electric vehicles (EVs) has continued to rise to 13.1% of all new car sales in Q2 2025, per data from the Electric Vehicle Council (EVC).

The need to not just revisit, but reimagine topics such as maximum demand, phase balance and energy systems is very real.

It has become clear during the first half of 2025 that the next edition of AS/NZS 3000 will not just be another edition. Three topics are driving this reimagination of some core principles: Earthing, energy systems and EV charging.

The current edition of AS/NZS 3000 makes a fleeting connection between our multiple earthed neutral (MEN) earthing system and the internationally described TN-C-S system. EL-001 intends to incorporate new requirements and guidance for all earthing systems described in IEC 60364-1 Low-voltage electrical installations – Part 1: Fundamental principles, assessment of general characteristics, definitions.

This includes earthing systems such as TT, IT and TN, which are deployed at differing scales around the world. While our MEN, or TN-C-S, earthing system has served Australia and New Zealand well and is expected to remain the predominant earthing system, challenges such as providing an adequate supply in remote areas may necessitate the deployment of a TT earthing system. Each earthing system presents unique opportunities and challenges in the provision of electrical safety.

The imminent publication of the sixth edition of IEC 60364-1 will redefine what we have always known as ‘earthing systems’ as ‘electric systems’. The sixth edition will also provide more detailed requirements for systems with more than one source of supply.

This is where EL-001 are carefully considering the interaction of multiple sources of supply and our MEN system. Terminology such as “electricity generation systems”, the existing title for AS/NZS 3000 Section 7.3, no longer accurately describes the reality of multiple sources of supply.

Questions such as: Will a single earth electrode be sufficient when an electrical installation operates in island mode in the event of a grid failure? Need to be considered.

EL-001 intend to include new recommendations and requirements when multiple sources of supply exist within an electrical installation. This is particularly important when multiple supplies are connected to the same busbar. With only one supply, the relevant protective device is sized to protect the busbar. When a second supply is added, there is a potential for the current flowing through the busbar to exceed its rating.

In larger systems, temperature rise must also be carefully considered. In the instance that one of the additional supplies is bi-directional, for example, a battery, the considerations become even more complex.

These considerations are not foreign to large and complex installations, where engineered designs can accommodate such challenges. EL-001 are faced with the challenge of providing requirements for multiple supplies that are equally consistent for the smallest of installations, all the way through to large and complex installations.

The existing informative guidance in AS/NZS 3000 Appendix P for EV charging applications requires 100% of the rated capacity of an EV charger to be used for determining the maximum demand of the respective sub-circuit.

At scale, this requirement has presented many issues for the industry. EL-001 are considering how technologies such as Electrical Energy Management Systems (EEMS) can be used to redefine maximum demand considerations, thus creating more efficient electrical installations through astute deployment of infrastructure.

International standards such as IEC 60364-7-722 and overseas standards such as BS 7671, the UK electrical installation standard, have already considered the interaction between earthing systems and EV charging. EL-001 are studying developments in both standards to determine if our MEN (TN-C-S) system provides adequate electric shock protection for all EV charging applications.

The most recent changes in BS 7671 are particularly relevant as the UK also deploys a TN-C-S earthing system known as Protective Multiple Earthing (PME). While the UK PME system does slightly differ from our MEN system, they are both TN-C-S systems. Not surprisingly, Australia and the UK have a shared experience with neutral faults. It is partly for this reason that BS 7671 prohibits the use of a PME earthing facility as the means of earthing an EV charging point when charging could be expected to occur outside, unless specific countermeasures are used.

EL-001 have recognised that significant explanation as to the merits and details behind each of these changes will be required between now and mid-2027. Together with Standards Australia, nominating organisations that are represented on EL-001 each have a role to play in animating these discussions with industry.

I encourage everyone in the industry to keep an eye out for information sessions. Companies such as Schneider Electric will be doing their best to keep the industry informed of what is expected, so you can ensure your business is ready.