While the RCD requirements for new installations seems to be understood, there is still some confusion regarding residential properties for sale or rent. Below is an article published by Building and Energy to clarify the requirements.
Under the Electricity Regulations 1947 all residential premises sold, rented or hired must have all socket outlets and lighting final sub-circuits protected by at least 2 RCDs. It is also essential to ensure that there are no more than 3 final sub-circuits per RCD and the lighting circuits (if 2 or more) are separated over the RCDs. Further details appear in the Electricity Regulations 1947, Regulations 12 to 16 which can be downloaded here.
The new 2018 edition of AS/NZS 3000:2018, Wiring Rules requires all circuits in residential premises to be RCD protected but this does not apply to existing residences. It only applies to residences constructed after 1 January 2019. There has been no change to the rules applying to RCDs required in residences being sold, rented or hired.
However, owners may, if they wish, fit RCDs to an existing residence constructed prior to 1 January 2019 to protect all the final sub-circuits. This is optional and not mandatory.
If an electrical contractor is engaged to verify that RCDs are fitted to a residence, subject to sale, rent or hire, he/she needs to ensure that at a minimum, RCDs are fitted to all circuits as required by the Electricity Regulation 1947 and not to AS/NZS 3000:2018, Wiring Rules.