Thanks for your replies!

Design considerations in Europe are slightly different. Mains voltage is specified as x V (usually 230/400) +/- 10% from the distribution network operator and then 0.5% voltage drop from the separation point to the meter and 3% from the meter to the last point of the circuit. Appliances are supposed to operate within those limits if their nameplate rating is 230 or 400 V. For general purpose lighting or outlet circuits, the rating of the fuse/MCB is taken as the design current for voltage drop calculations, i.e. the 3% are at full load regardless of the actual voltage at the service entrance.

Depending on the type of fault protection, voltage drop/loop impedance can become a safety issue. In the event of a line - earth fault the supply is required to be disconnected within 200 ms, i.e. if there is no RCD protection, the magnetic trip of the MCB has to operate. If there's an RCD/GFCI impedance is much less critical.