Pole pigs in Australia (Europe?) vs North America

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I was looking at buying a refurbished pole pig and before approaching them I'd like to make sure I am understanding this right. Apologies if this is obvious to some people, but the actual mechanics of three phase power systems are not really my thing, and I'd rather they not turn me away when they learn it's for a TC.

In North America, which is where I've seen a lot of other hobbyists doing pole pig related things, pigs always seem to have a single HV connection, and I asume that the other primary connection is throgh the case and is connected to a ground (not sure what ground as I am pretty sure most US networks use a three wire HV feeder like we do?). But here in Australia, this type of pole pig is only used in SWER connections in rural areas.

Instead, most single phase pigs have two HV connections, connected across two of the three HV feeder phases. In some rural areas, only two HV feeder phases are used.

I am guessing (but am not sure), that the US system is basically a single leg of a three-phase Y setup, and the Australian system is two legs of a three phase delta setup? I am guessing that SWER is also similar to the North American system but with earth ground. I have heard of SWER isolating transformers which I assume are delta-Y transformers.

[klugesmith]

In my experience (in California), pole transformers generally have two HV bushings, and pick up two of the three HV wires that run pole to pole.   Some roads have only two wires.   I have never seen single wire earth return.

[MRMILSTAR]

There are 2 main types that I have seen in the US to supply homes. The most common type has 2 HV bushings and 3 LV connections. For home service, the LV connections comprise a center-tapped 240 volt source.

The other less common type is generally found in rural areas where only a single HV wire is on the poles. These have a single HV bushing and 3 LV connections. One HV side of the transformer is connected to the case. The case is then connected to the ground which supplies the return path. Ground conditions have to be suitable to use these.

[Download]

There are 2 main types that I have seen in the US to supply homes. The most common type has 2 HV bushings and 3 LV connections. For home service, the LV connections comprise a center-tapped 240 volt source.

Easily half of the pole pigs tagged as being in US on Wikimedia Commons are of the single HV bushing type (and most of the smaller ones), so I am slightly confused.

https://commons.wikimedia.org/wiki/Category:Pole-mounted_transformers_in_the_United_States

The other less common type is generally found in rural areas where only a single HV wire is on the poles. These have a single HV bushing and 3 LV connections. One HV side of the transformer is connected to the case. The case is then connected to the ground which supplies the return path. Ground conditions have to be suitable to use these.

That basically describes SWER. Odd given I've only heard about it being used in the US in Alaska.