I have never seen some of the above mentioned configurations... And never heard of them at all. As far as I know South African electricity is supplied at 230V phase-ground which equates to 400v phase-phase. (+- 10%)
Three phase power simply means that all three phases are brought into the premises. These phases are 120 degrees apart from each other.
You can have three phase power and your neighbor can have one phase power. All that this means is that you have all three wires coming into your house, but your neighbor only has one of the three. Devices in your residence will then draw power the same way as in any other house (3 phase or 1 phase).
Your lights and plugs circuits will only draw from one phase and neutral. Same for most stoves, geysers, ovens and basically all residential appliances I can think of (Except some of the very big, fancy cooking ranges and instant electric water heaters). In nearly every house with three phase power, their are never actually any three phase loads. The only difference is that the circuits in your house (which are all normally 1 phase) are shared amongst the three phases.
There is ONE exception in South Africa to this and that is in the EXTREME rural Karoo some farms and houses are supplied by a configuration called SWER (Single Wire Earth Return), This is extremely rare, it is not known by most electricians, and most of them will never encounter a SWER installation in their careers.
Your house will always have Neutrals because light circuits and plug circuits are always single phase(Current flows from 1 phase to Neutral).
3 phase loads (Both star and Delta do exist) But nearly every house will not have any 3 phase loads for the following reasons.
1) Most houses are 1ph and therefore it makes no sense to design residential appliances for 3ph as they can not be used in most houses
2) Houses do not normally have large motors or large loads and therefore their is little benefit to having a load be 3ph.
3) The three phase load will require a 3 phase circuit which will probably be run just for that device therefore it is inconvenient
The only appliances I have ever seen in houses that were 3 phase are:
- A geyser element (for a large 500l geyser) (It was connected in delta)
- An instant/Tankless hot water heater (Like a gas geyser, but electric) These require more than 20kw and sometimes over 30kw
- Large fancy oven/stove ranges
Most of the time when a house has 3 phase, it is wired exactly like a single phase house, just instead of one live wire, there are three, and these three wires act just like 3 (separate... they should never be shorted together) electrical supplies.
Edit: This is not a crash course in 3 phase... This is just what I know from common knowledge and spending some time DIY installing solar, rewiring a 3phase DB and spending time with some electrician friends of mine.
Edit 2: SWER supplies are very interesting and I am happy to talk more about them if anyone is curious.
