However I am aware that most appliances that would use 30 - 40 amps are required to be wired in and not by way of an outlet. That's not to say that always the case, and since so much of the rural areas in my parts are single phase there's been times working around a rough country shed -- it'd be more than one outlet plus 15 plug that's melted because someone was pushing their luck with a hot welder.
I used to have an extensive book on the code two or three decades ago ... but code changes - possibly for when common sense ... doesn't. Below [1] might offer a guide as to how it's supposed to happen down under.
[1] https://cccengineering.com.au/design-memos/as-3000-explained...