Given that PC power supplies are essentially a world-wide commodity
item, I'd have thought that Australia would have inherited any
improvements mandated in other jurisdictions, even if there were no
local regulations.
A power supply can be designed with harmonic correction. Then that
same circuit may be 'forgotten' when the same supply is sold in
Australia. Harmonic suppression is required in Europe. A same supply
without that harmonic compensation is sold elsewhere with a slightly
different model number.
A power supply manufacturer may not need to meet local
requirements. A computer that must suppress harmonics is the
responsibility of the computer assembler - not of the power supply
manufacturer. Therefore many power supply manufacturers dump into the
market products that violate local standards. He is not responsible.
The computer assembler who buys his supplies may be responsible for
meeting those code requirements. Unfortunately many computer
assemblers have so little technical knowledge as to not even know what
harmonics are.
I have no idea what that market discussion has to do with
harmonics. I believe the original question was about a computer
operating on a generator. Computer power supplies must be so robust
as to make those square waves (modified sine waves) irrelevant. But
again, did a power supply manufacturer bother to meet industry
standards? Or simply forget some components to sell a cheaper supply
also for higher profits?