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:



{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.

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.

Trumpy:
Although I probably will never see one of these, I have to ask..
Is that a mfg defect, or is the contact 'bent' from usage?

Trumpy - I have found a very similar thing happens here in the UK. Particularly with some sockets from the 1970s made by Volex. It seems the constant in-and-out of the plug over time makes the contacts lose their spring tension. We also probably have thousands still in use that no one has discovered yet.

John,
It's caused by normal wear and tear during use over that time-span.

From the pic, it looks like the earth pin is longer than the other two, so as it makes contact first. That could impose a side load on the earth contacts before the plug gets aligned properly. As such, as you say, this fault will exist on a lot of other sockets. It looks solidly built, with good size brass screws and copper sections. Is there any function to the strange 'overlap' feature at the back of the pic?
And did you cut yourself taking it apart, Mike?

Alan,
The earth pin on an AS/NZ plug is always longer than the other two pins, so that it "makes" first and "breaks" last.

The overlap at the back is for the switch mechanism of the socket, there is a plastic toggle that sits on top of the strip of brass, it is held in place by the front plate.

Them reddish spots are actually part of the "plastic" moulding, this was from a time when plastic was first being used to make electrical accessories, as opposed to the bakelite that was used in earlier fittings.
This plastic isn't unlike bakelite, as in, if you aren't careful and drop a socket like this on a bare concrete floor, you can almost put money on the fact of it breaking into at least 3 pieces.

Looks like they used random color granulate or even recycled plastics. There were some switch boxes here where they used odd coloured leftovers all thrown together because they were cheaper.

I have struck a few of them over the years, The dreaded spreaded earth contacts of the PDL 60 series.

I still have quite a few of them in my house, must do a loop impedance test on them.

It always seem to be the earths having the problems (longer pin on plug ) or poor beryllium copper which looses it's tensile strength.

Never seen spreaded phase or neutral contacts.

An other fault of these plugs is that they fill up with dust over the years.

It is rather strange how that's true, Ray.
Mind you with mandatory earth-loop testing here, hopefully most of these sockets will be weeded out in due course.

Trumpy:

I have to ask, is the earth contact a single piece with spring tension, or is it two pieces, like two "L"'s that are held in place by a stud under that nice termination lug?

Or, is your earth pin much wider than the other pins on the male cap?

John,
One side of the contact is brass, the other side is copper.
Usually there is quite a bit of "spring tension" between the two contacts, that holds the pin of the plug in place.
As far as I'm aware, the pins are all the same size, it's just that the earth is longer.

Thanks Mike! It's kind of hard to tell from the pic, but I got it now.