Access Canberra’s Electrical Inspection team has outlined several important updates to the AS/NZS 4777.1 standard, which was officially released on 23 August 2024 and took effect in February 2025. These updates are crucial for any electrician working with inverter energy systems (IESs).
1) Updated Supply Type Definitions
To improve clarity and align with AS/NZS 3000, the terminology around supply types has been revised:
- Normal Supply – Grid power managed via the main switch
- Supplementary Supply – Operates in parallel with the grid but cannot function alone
- Alternative Supply – Activates a backup source when the grid goes down
- Independent Supply – Powers the installation autonomously, using the grid only to recharge
- Substitute Supply – Powers a single outlet directly
2) Inverter Main Switch Limits
Switchboards that include loads can now have a maximum of two inverter main switches. If more than two are present, a single master switch must be used to isolate all inverters.
3) Better Alignment with Other Standards
AS/NZS 4777.1 has been brought into closer alignment with related standards such as AS/NZS 5139, 4777.2, and 5033. A notable change includes the removal of the 600V DC voltage limit, aligning with the updates in AS/NZS 5033.
4) Phase Balance Restrictions
For single-phase systems, a maximum capacity of 30kVA is now permitted, depending on the available grid supply and the system’s overcurrent protection.
5) Inverter Power Sharing Devices (IPSDs)
New provisions address shared solar scenarios, such as multi-dwelling units, where a single PV system may be shared between occupants using IPSDs.
6) Vehicle-to-Grid (V2G) Integration
Electric vehicles can now be more effectively integrated into the energy ecosystem, with support for drawing power from and feeding energy back to the grid.
While this summary covers the key updates, it’s not a complete list. Electricians are strongly encouraged to review AS/NZS 4777.1:2024 in full to ensure all installation practices meet the current requirements.
