I was in a house yesterday, doing some repairs to a lighting circuit, when the home owner asked me to check the wiring, etc, for her.
I started off checking the socket-outlet circuits with an Earth Loop tester, all seemed to be OK, until I tested a socket in the laundry, that the dryer was plugged into.

It failed miserably, in fact, as far as the test result went, it said there was no Earth connection at all.
I isolated the circuit and took the socket off the wires in the mounting block and had a look at the socket contacts, here is what I found:

[Linked Image from electrical-photos.com]

{Bear in mind, that I'd already removed the actual face of the socket, before I took this picture.}

What we have here, is a socket, of about 1960's era manufacture, it is known as a PDL Cat No. 60.
If you see the other two contacts for the phase and neutral pins of the plug-top, that is the way they are supposed to look, with the two strips almost touching.
If you now look at the Earth contact to the front of the picture, it's splayed wide open. whistle

There are probably hundreds, if not thousands of these sockets in houses around New Zealand, with splayed Earth contacts like this one, the thing that worries me the most is the fact that a lot of people don't even know they are in this condition.

I would never have known unless I'd done an Earth loop test either.
Just something for you NZ sparkies/inspectors to be aware of.