Also there should have been a fused isolator used for the isolation of the armoured cables as otherwise the suppliers fuse is protecting the whole length of the cable including the SWA to the apartments.
Good point. It's safe enough without (assuming the SWA is suitably rated), but rather inconvenient if a fault takes out the PoCo fuse. I would have thought that the utility would have objected to this, but then with the actual supply work and the metering being handled by different companies now, there's probably no coordination to have caught it.
because they are glanded into the same metallic enclosure they will now be sharing an earth connection.
If the plumbing system is all metallic and is properly bonded, there will be parallel paths anyway. I wonder how the earthing has been handled in that trunking and in the apartment? It could be 4-core SWA with the armor not connected at the load end.
By the way, I reckon the load on the E7 circuit must be pretty light. It seems that the apartment does not have storage heaters, but instead has been fitted with the Dimplex pilot-wire controlled panel heaters, so they'll be on the permanent live. Unless there's something else I don't know about, the only appliance on the off-peak supply seems to be the water heater.
