Adam,
In the U.S. it's also possible to find a common bus in the main panel to which both neutrals (grounded circuit conductors) and earths (grounding conductors in NEC parlance) are connected. They're kept strictly separate in sub-panels and beyond, as here, with an exception for ranges and dryers which for many years were allowed to have their frames grounded to the neutral.
In the British PME (Protective Multiple Earthing) system, the installation is grounded to the neutral only at that cut-out ahead of the meter. Neutral & earth/ground are kept completely separate from that point on, so main panels have an isolated neutral bus and separate earth/grounding bar.
To return to this specific case, I've had some of my guesses about the building confirmed. It's a 3-story block with two apartments per floor. These pictures are from the U.K. 1st/U.S. 2nd floor, so I think we can assume that the shared meter cupboards are probably built one above the other and the two MICC(?) cables running vertically on the cable tray must therefore be the feeders to the top floor.
What's at ground or basement level to feed these is anybody's guess. A single 3-phase feeder to a PoCo-owned distribution panel with OCPD for each subfeed? Maybe seven individual 1-ph feeders (allowing one for communal services) from the street which have the usual fused cutout?
We're used to seeing all sorts of odd meter locations in old places which have been converted into flats, but on a new build I wonder why it was done like this at all. If there's a common utility room at the bottom, why not just put all the meters and isolators in there, then the SWA subfeeds could have gone directly to each apartment, eliminating the need for a separate meter closet/cupboard on each floor entirely.
The only reason I can think of for wanting the meters near to the apartment they serve would be if some flats were going to be using prepayment card/key meters, or somebody thought there was a chance that they might do so in the future.
I'm just thinking out loud here, of course. It would certainly be interesting to see what's at the common supply point.
