Hi Paul,
Split-load arrangements were common in my experience in South Africa. Main DP breaker fed CBs to Stove, Water Heater, lights and finally an GFCI which in turn fed CBs covering all outlets (interior and exterior) as well as feeds to garage etc. What was needed to be GFCI protected varied between Provinces as well as through time.
There were not separate live busbars in the in the main panel as all breakers were mounted on a common grounded frame. Feed was into the top of the CB and, where common to a number of CBs, comprised a 2mm thick flat copper comb with prongs spaced on the breaker centres which I think was 12.7mm (very metric!). Extra breakers were usually fed with small inverted “U” shape loops of suitably sized insulated wire – usually 4 sq mm. Screw connectors in the CB clamped the feed-wire, comb, and/or additional loops. Hence in a South African panel there would usually be two sets of combs and importantly two separate neutral busbars as well as a grounding one.
I remember one set-up confounding me for a while where the left-hand neutral bar corresponded with all the GFCIs on the right-hand side of the box and the right-hand neutral bar was wired with the non-GFCI on the left-hand side. How it got set-up like this in the first place I do not know, but it had me chasing rouge GFCI trips after adding a bathroom heater circuit until I discovered the switch.
BTW South Africa went metric in 1970 and after that date anything imperial was deemed illegal. My wife as a young girl at the time remembers receiving notice from the Post Office that an item posted from abroad was an illegal item and had been seized by the authorities. It was found to be a 6” school ruler – a present from her grandmother in Scotland which bore both imperial and metric measures!
