Originally Posted by Nev
on another forum

That wouldn't be http://www.renovateforum.com/forumdisplay.php?f=78
by any chance would it?
It's also been a hot topic in "Silicon Chip" magazine for a couple of years now.
One gets the impression from reading the threads there that there is a still a closed shop attitude and that's the real reason. That most of the world doesn't have such restrictions, and any more problems as a result, always meets with a blank response. One excuse that comes up is that U.S homeowners are at less risk because of the 120V supply, and Australians mustn't be let near something so deadly as 240V for their own safety. The fact that U.S homes do actually have 240V fed into them is conveniently ignored.
At this point in time the union power in Australia is just too strong and I don't see common sense coming to fruition for quite some time. In the meantime, Australians will continue to do electrical DIY as they have always done (bad and good work), so it's not like there's suddenly going to be loss of jobs for the tradies.
The sensible response is to follow the NZ model, and educate rather than deny.