Interesting. The Wiring Regulations were updated in 2018 and from November 2018 there were new RCD regulations to conform to. The regulations beefed up the requirement for RCD’s in many/most domestic circumstances and brought NZ more in line with AU requirements.
More interestingly, there are 294 new requirements as from Nov 2018, for wiring, compared with a very much smaller set of changes previously - 87 over the previous 30-odd years.
More good reasons for using an electrician, I guess.
The 2018 requirements, thankfully, exclude New Zealand. The new rules (which AU have adopted but we have held back for obvious amendment reasons) stipulate that anything 32A and under needs to be on RCD - this would cause all kinds of extra nuisance tripping with elements and compressors!
There are exceptions for having to install an RCD on power/light circuit -- if you are MOVING an outlet, or if you are replacing/joining cabling you do not have to put the item on RCD. Bathroom / wet area / spa [etc] power points have required RCD protection for many many years (>20), however.