The 230V network represents 83 % of the cable lengths. These cables have 3 wires for the 3 phases. You get 230V single-phase power by connecting across two phases.
The 400V network represents 17 % of the total. This network has 4 wires for the 3 phases and one wire for the neutral conductor. You get 230V single-phase power by connecting between one of the 3 phases and the neutral conductor. 400V power is available between two phases.
